This patch adds a new file discard.c to maintain discard related
function separately.

BTW, fix below checkpatch errors:

ERROR: space required before the open brace '{'
+               } else if (issued == -1){

ERROR: spaces required around that ':' (ctx:VxW)
+                               devi, sbi->s_ndevs ? FDEV(devi).path: "",

Signed-off-by: Chao Yu <[email protected]>
---
 fs/f2fs/Makefile  |    2 +-
 fs/f2fs/discard.c | 1009 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/f2fs/f2fs.h    |   34 +-
 fs/f2fs/segment.c |  991 +---------------------------------------------------
 4 files changed, 1037 insertions(+), 999 deletions(-)
 create mode 100644 fs/f2fs/discard.c

diff --git a/fs/f2fs/Makefile b/fs/f2fs/Makefile
index 776c4b936504..43513c7b69aa 100644
--- a/fs/f2fs/Makefile
+++ b/fs/f2fs/Makefile
@@ -3,7 +3,7 @@ obj-$(CONFIG_F2FS_FS) += f2fs.o
 
 f2fs-y         := dir.o file.o inode.o namei.o hash.o super.o inline.o
 f2fs-y         += checkpoint.o gc.o data.o node.o segment.o recovery.o
-f2fs-y         += shrinker.o extent_cache.o sysfs.o
+f2fs-y         += shrinker.o extent_cache.o sysfs.o discard.o
 f2fs-$(CONFIG_F2FS_STAT_FS) += debug.o
 f2fs-$(CONFIG_F2FS_FS_XATTR) += xattr.o
 f2fs-$(CONFIG_F2FS_FS_POSIX_ACL) += acl.o
diff --git a/fs/f2fs/discard.c b/fs/f2fs/discard.c
new file mode 100644
index 000000000000..af6efb3c797b
--- /dev/null
+++ b/fs/f2fs/discard.c
@@ -0,0 +1,1009 @@
+/*
+ * f2fs discard support
+ *
+ * Copyright (c) 2018 Chao Yu <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/f2fs_fs.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/sched/signal.h>
+
+#include "f2fs.h"
+#include "segment.h"
+#include "gc.h"
+#include <trace/events/f2fs.h>
+
+static struct kmem_cache *discard_entry_slab;
+static struct kmem_cache *discard_cmd_slab;
+
+static struct discard_cmd *__create_discard_cmd(struct f2fs_sb_info *sbi,
+               struct block_device *bdev, block_t lstart,
+               block_t start, block_t len)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       struct list_head *pend_list;
+       struct discard_cmd *dc;
+
+       f2fs_bug_on(sbi, !len);
+
+       pend_list = &dcc->pend_list[plist_idx(len)];
+
+       dc = f2fs_kmem_cache_alloc(discard_cmd_slab, GFP_NOFS);
+       INIT_LIST_HEAD(&dc->list);
+       dc->bdev = bdev;
+       dc->lstart = lstart;
+       dc->start = start;
+       dc->len = len;
+       dc->ref = 0;
+       dc->state = D_PREP;
+       dc->error = 0;
+       init_completion(&dc->wait);
+       list_add_tail(&dc->list, pend_list);
+       atomic_inc(&dcc->discard_cmd_cnt);
+       dcc->undiscard_blks += len;
+
+       return dc;
+}
+
+static struct discard_cmd *__attach_discard_cmd(struct f2fs_sb_info *sbi,
+                               struct block_device *bdev, block_t lstart,
+                               block_t start, block_t len,
+                               struct rb_node *parent, struct rb_node **p)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       struct discard_cmd *dc;
+
+       dc = __create_discard_cmd(sbi, bdev, lstart, start, len);
+
+       rb_link_node(&dc->rb_node, parent, p);
+       rb_insert_color(&dc->rb_node, &dcc->root);
+
+       return dc;
+}
+
+static void __detach_discard_cmd(struct discard_cmd_control *dcc,
+                                                       struct discard_cmd *dc)
+{
+       if (dc->state == D_DONE)
+               atomic_dec(&dcc->issing_discard);
+
+       list_del(&dc->list);
+       rb_erase(&dc->rb_node, &dcc->root);
+       dcc->undiscard_blks -= dc->len;
+
+       kmem_cache_free(discard_cmd_slab, dc);
+
+       atomic_dec(&dcc->discard_cmd_cnt);
+}
+
+static void __remove_discard_cmd(struct f2fs_sb_info *sbi,
+                                                       struct discard_cmd *dc)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+
+       trace_f2fs_remove_discard(dc->bdev, dc->start, dc->len);
+
+       f2fs_bug_on(sbi, dc->ref);
+
+       if (dc->error == -EOPNOTSUPP)
+               dc->error = 0;
+
+       if (dc->error)
+               f2fs_msg(sbi->sb, KERN_INFO,
+                       "Issue discard(%u, %u, %u) failed, ret: %d",
+                       dc->lstart, dc->start, dc->len, dc->error);
+       __detach_discard_cmd(dcc, dc);
+}
+
+static void f2fs_submit_discard_endio(struct bio *bio)
+{
+       struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
+
+       dc->error = blk_status_to_errno(bio->bi_status);
+       dc->state = D_DONE;
+       complete_all(&dc->wait);
+       bio_put(bio);
+}
+
+static void __check_sit_bitmap(struct f2fs_sb_info *sbi,
+                               block_t start, block_t end)
+{
+#ifdef CONFIG_F2FS_CHECK_FS
+       struct seg_entry *sentry;
+       unsigned int segno;
+       block_t blk = start;
+       unsigned long offset, size, max_blocks = sbi->blocks_per_seg;
+       unsigned long *map;
+
+       while (blk < end) {
+               segno = GET_SEGNO(sbi, blk);
+               sentry = get_seg_entry(sbi, segno);
+               offset = GET_BLKOFF_FROM_SEG0(sbi, blk);
+
+               if (end < START_BLOCK(sbi, segno + 1))
+                       size = GET_BLKOFF_FROM_SEG0(sbi, end);
+               else
+                       size = max_blocks;
+               map = (unsigned long *)(sentry->cur_valid_map);
+               offset = __find_rev_next_bit(map, size, offset);
+               f2fs_bug_on(sbi, offset != size);
+               blk = START_BLOCK(sbi, segno + 1);
+       }
+#endif
+}
+
+/* this function is copied from blkdev_issue_discard from block/blk-lib.c */
+static void __submit_discard_cmd(struct f2fs_sb_info *sbi,
+                                               struct discard_policy *dpolicy,
+                                               struct discard_cmd *dc)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
+                                       &(dcc->fstrim_list) : &(dcc->wait_list);
+       struct bio *bio = NULL;
+       int flag = dpolicy->sync ? REQ_SYNC : 0;
+
+       if (dc->state != D_PREP)
+               return;
+
+       if (is_sbi_flag_set(sbi, SBI_NEED_FSCK))
+               return;
+
+       trace_f2fs_issue_discard(dc->bdev, dc->start, dc->len);
+
+       dc->error = __blkdev_issue_discard(dc->bdev,
+                               SECTOR_FROM_BLOCK(dc->start),
+                               SECTOR_FROM_BLOCK(dc->len),
+                               GFP_NOFS, 0, &bio);
+       if (!dc->error) {
+               /* should keep before submission to avoid D_DONE right away */
+               dc->state = D_SUBMIT;
+               atomic_inc(&dcc->issued_discard);
+               atomic_inc(&dcc->issing_discard);
+               if (bio) {
+                       bio->bi_private = dc;
+                       bio->bi_end_io = f2fs_submit_discard_endio;
+                       bio->bi_opf |= flag;
+                       submit_bio(bio);
+                       list_move_tail(&dc->list, wait_list);
+                       __check_sit_bitmap(sbi, dc->start, dc->start + dc->len);
+
+                       f2fs_update_iostat(sbi, FS_DISCARD, 1);
+               }
+       } else {
+               __remove_discard_cmd(sbi, dc);
+       }
+}
+
+static struct discard_cmd *__insert_discard_tree(struct f2fs_sb_info *sbi,
+                               struct block_device *bdev, block_t lstart,
+                               block_t start, block_t len,
+                               struct rb_node **insert_p,
+                               struct rb_node *insert_parent)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       struct rb_node **p;
+       struct rb_node *parent = NULL;
+       struct discard_cmd *dc = NULL;
+
+       if (insert_p && insert_parent) {
+               parent = insert_parent;
+               p = insert_p;
+               goto do_insert;
+       }
+
+       p = __lookup_rb_tree_for_insert(sbi, &dcc->root, &parent, lstart);
+do_insert:
+       dc = __attach_discard_cmd(sbi, bdev, lstart, start, len, parent, p);
+       if (!dc)
+               return NULL;
+
+       return dc;
+}
+
+static void __relocate_discard_cmd(struct discard_cmd_control *dcc,
+                                               struct discard_cmd *dc)
+{
+       list_move_tail(&dc->list, &dcc->pend_list[plist_idx(dc->len)]);
+}
+
+static void __punch_discard_cmd(struct f2fs_sb_info *sbi,
+                               struct discard_cmd *dc, block_t blkaddr)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       struct discard_info di = dc->di;
+       bool modified = false;
+
+       if (dc->state == D_DONE || dc->len == 1) {
+               __remove_discard_cmd(sbi, dc);
+               return;
+       }
+
+       dcc->undiscard_blks -= di.len;
+
+       if (blkaddr > di.lstart) {
+               dc->len = blkaddr - dc->lstart;
+               dcc->undiscard_blks += dc->len;
+               __relocate_discard_cmd(dcc, dc);
+               modified = true;
+       }
+
+       if (blkaddr < di.lstart + di.len - 1) {
+               if (modified) {
+                       __insert_discard_tree(sbi, dc->bdev, blkaddr + 1,
+                                       di.start + blkaddr + 1 - di.lstart,
+                                       di.lstart + di.len - 1 - blkaddr,
+                                       NULL, NULL);
+               } else {
+                       dc->lstart++;
+                       dc->len--;
+                       dc->start++;
+                       dcc->undiscard_blks += dc->len;
+                       __relocate_discard_cmd(dcc, dc);
+               }
+       }
+}
+
+static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
+                               struct block_device *bdev, block_t lstart,
+                               block_t start, block_t len)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
+       struct discard_cmd *dc;
+       struct discard_info di = {0};
+       struct rb_node **insert_p = NULL, *insert_parent = NULL;
+       block_t end = lstart + len;
+
+       mutex_lock(&dcc->cmd_lock);
+
+       dc = (struct discard_cmd *)__lookup_rb_tree_ret(&dcc->root,
+                                       NULL, lstart,
+                                       (struct rb_entry **)&prev_dc,
+                                       (struct rb_entry **)&next_dc,
+                                       &insert_p, &insert_parent, true);
+       if (dc)
+               prev_dc = dc;
+
+       if (!prev_dc) {
+               di.lstart = lstart;
+               di.len = next_dc ? next_dc->lstart - lstart : len;
+               di.len = min(di.len, len);
+               di.start = start;
+       }
+
+       while (1) {
+               struct rb_node *node;
+               bool merged = false;
+               struct discard_cmd *tdc = NULL;
+
+               if (prev_dc) {
+                       di.lstart = prev_dc->lstart + prev_dc->len;
+                       if (di.lstart < lstart)
+                               di.lstart = lstart;
+                       if (di.lstart >= end)
+                               break;
+
+                       if (!next_dc || next_dc->lstart > end)
+                               di.len = end - di.lstart;
+                       else
+                               di.len = next_dc->lstart - di.lstart;
+                       di.start = start + di.lstart - lstart;
+               }
+
+               if (!di.len)
+                       goto next;
+
+               if (prev_dc && prev_dc->state == D_PREP &&
+                       prev_dc->bdev == bdev &&
+                       __is_discard_back_mergeable(&di, &prev_dc->di)) {
+                       prev_dc->di.len += di.len;
+                       dcc->undiscard_blks += di.len;
+                       __relocate_discard_cmd(dcc, prev_dc);
+                       di = prev_dc->di;
+                       tdc = prev_dc;
+                       merged = true;
+               }
+
+               if (next_dc && next_dc->state == D_PREP &&
+                       next_dc->bdev == bdev &&
+                       __is_discard_front_mergeable(&di, &next_dc->di)) {
+                       next_dc->di.lstart = di.lstart;
+                       next_dc->di.len += di.len;
+                       next_dc->di.start = di.start;
+                       dcc->undiscard_blks += di.len;
+                       __relocate_discard_cmd(dcc, next_dc);
+                       if (tdc)
+                               __remove_discard_cmd(sbi, tdc);
+                       merged = true;
+               }
+
+               if (!merged) {
+                       __insert_discard_tree(sbi, bdev, di.lstart, di.start,
+                                                       di.len, NULL, NULL);
+               }
+ next:
+               prev_dc = next_dc;
+               if (!prev_dc)
+                       break;
+
+               node = rb_next(&prev_dc->rb_node);
+               next_dc = rb_entry_safe(node, struct discard_cmd, rb_node);
+       }
+
+       mutex_unlock(&dcc->cmd_lock);
+}
+
+static int __queue_discard_cmd(struct f2fs_sb_info *sbi,
+               struct block_device *bdev, block_t blkstart, block_t blklen)
+{
+       block_t lblkstart = blkstart;
+
+       trace_f2fs_queue_discard(bdev, blkstart, blklen);
+
+       if (sbi->s_ndevs) {
+               int devi = f2fs_target_device_index(sbi, blkstart);
+
+               blkstart -= FDEV(devi).start_blk;
+       }
+       __update_discard_tree_range(sbi, bdev, lblkstart, blkstart, blklen);
+       return 0;
+}
+
+static void __issue_discard_cmd_range(struct f2fs_sb_info *sbi,
+                                       struct discard_policy *dpolicy,
+                                       unsigned int start, unsigned int end)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
+       struct rb_node **insert_p = NULL, *insert_parent = NULL;
+       struct discard_cmd *dc;
+       struct blk_plug plug;
+       int issued;
+
+next:
+       issued = 0;
+
+       mutex_lock(&dcc->cmd_lock);
+       f2fs_bug_on(sbi, !__check_rb_tree_consistence(sbi, &dcc->root));
+
+       dc = (struct discard_cmd *)__lookup_rb_tree_ret(&dcc->root,
+                                       NULL, start,
+                                       (struct rb_entry **)&prev_dc,
+                                       (struct rb_entry **)&next_dc,
+                                       &insert_p, &insert_parent, true);
+       if (!dc)
+               dc = next_dc;
+
+       blk_start_plug(&plug);
+
+       while (dc && dc->lstart <= end) {
+               struct rb_node *node;
+
+               if (dc->len < dpolicy->granularity)
+                       goto skip;
+
+               if (dc->state != D_PREP) {
+                       list_move_tail(&dc->list, &dcc->fstrim_list);
+                       goto skip;
+               }
+
+               __submit_discard_cmd(sbi, dpolicy, dc);
+
+               if (++issued >= dpolicy->max_requests) {
+                       start = dc->lstart + dc->len;
+
+                       blk_finish_plug(&plug);
+                       mutex_unlock(&dcc->cmd_lock);
+
+                       schedule();
+
+                       goto next;
+               }
+skip:
+               node = rb_next(&dc->rb_node);
+               dc = rb_entry_safe(node, struct discard_cmd, rb_node);
+
+               if (fatal_signal_pending(current))
+                       break;
+       }
+
+       blk_finish_plug(&plug);
+       mutex_unlock(&dcc->cmd_lock);
+}
+
+static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
+                                       struct discard_policy *dpolicy)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       struct list_head *pend_list;
+       struct discard_cmd *dc, *tmp;
+       struct blk_plug plug;
+       int i, iter = 0, issued = 0;
+       bool io_interrupted = false;
+
+       for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
+               if (i + 1 < dpolicy->granularity)
+                       break;
+               pend_list = &dcc->pend_list[i];
+
+               mutex_lock(&dcc->cmd_lock);
+               if (list_empty(pend_list))
+                       goto next;
+               f2fs_bug_on(sbi, !__check_rb_tree_consistence(sbi, &dcc->root));
+               blk_start_plug(&plug);
+               list_for_each_entry_safe(dc, tmp, pend_list, list) {
+                       f2fs_bug_on(sbi, dc->state != D_PREP);
+
+                       if (dpolicy->io_aware && i < dpolicy->io_aware_gran &&
+                                                               !is_idle(sbi)) {
+                               io_interrupted = true;
+                               goto skip;
+                       }
+
+                       __submit_discard_cmd(sbi, dpolicy, dc);
+                       issued++;
+skip:
+                       if (++iter >= dpolicy->max_requests)
+                               break;
+               }
+               blk_finish_plug(&plug);
+next:
+               mutex_unlock(&dcc->cmd_lock);
+
+               if (iter >= dpolicy->max_requests)
+                       break;
+       }
+
+       if (!issued && io_interrupted)
+               issued = -1;
+
+       return issued;
+}
+
+static bool __drop_discard_cmd(struct f2fs_sb_info *sbi)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       struct list_head *pend_list;
+       struct discard_cmd *dc, *tmp;
+       int i;
+       bool dropped = false;
+
+       mutex_lock(&dcc->cmd_lock);
+       for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
+               pend_list = &dcc->pend_list[i];
+               list_for_each_entry_safe(dc, tmp, pend_list, list) {
+                       f2fs_bug_on(sbi, dc->state != D_PREP);
+                       __remove_discard_cmd(sbi, dc);
+                       dropped = true;
+               }
+       }
+       mutex_unlock(&dcc->cmd_lock);
+
+       return dropped;
+}
+
+void drop_discard_cmd(struct f2fs_sb_info *sbi)
+{
+       __drop_discard_cmd(sbi);
+}
+
+static unsigned int __wait_one_discard_bio(struct f2fs_sb_info *sbi,
+                                                       struct discard_cmd *dc)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       unsigned int len = 0;
+
+       wait_for_completion_io(&dc->wait);
+       mutex_lock(&dcc->cmd_lock);
+       f2fs_bug_on(sbi, dc->state != D_DONE);
+       dc->ref--;
+       if (!dc->ref) {
+               if (!dc->error)
+                       len = dc->len;
+               __remove_discard_cmd(sbi, dc);
+       }
+       mutex_unlock(&dcc->cmd_lock);
+
+       return len;
+}
+
+static unsigned int __wait_discard_cmd_range(struct f2fs_sb_info *sbi,
+                                               struct discard_policy *dpolicy,
+                                               block_t start, block_t end)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
+                                       &(dcc->fstrim_list) : &(dcc->wait_list);
+       struct discard_cmd *dc, *tmp;
+       bool need_wait;
+       unsigned int trimmed = 0;
+
+next:
+       need_wait = false;
+
+       mutex_lock(&dcc->cmd_lock);
+       list_for_each_entry_safe(dc, tmp, wait_list, list) {
+               if (dc->lstart + dc->len <= start || end <= dc->lstart)
+                       continue;
+               if (dc->len < dpolicy->granularity)
+                       continue;
+               if (dc->state == D_DONE && !dc->ref) {
+                       wait_for_completion_io(&dc->wait);
+                       if (!dc->error)
+                               trimmed += dc->len;
+                       __remove_discard_cmd(sbi, dc);
+               } else {
+                       dc->ref++;
+                       need_wait = true;
+                       break;
+               }
+       }
+       mutex_unlock(&dcc->cmd_lock);
+
+       if (need_wait) {
+               trimmed += __wait_one_discard_bio(sbi, dc);
+               goto next;
+       }
+
+       return trimmed;
+}
+
+static void __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
+                                               struct discard_policy *dpolicy)
+{
+       __wait_discard_cmd_range(sbi, dpolicy, 0, UINT_MAX);
+}
+
+/* This should be covered by global mutex, &sit_i->sentry_lock */
+void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       struct discard_cmd *dc;
+       bool need_wait = false;
+
+       mutex_lock(&dcc->cmd_lock);
+       dc = (struct discard_cmd *)__lookup_rb_tree(&dcc->root, NULL, blkaddr);
+       if (dc) {
+               if (dc->state == D_PREP) {
+                       __punch_discard_cmd(sbi, dc, blkaddr);
+               } else {
+                       dc->ref++;
+                       need_wait = true;
+               }
+       }
+       mutex_unlock(&dcc->cmd_lock);
+
+       if (need_wait)
+               __wait_one_discard_bio(sbi, dc);
+}
+
+void stop_discard_thread(struct f2fs_sb_info *sbi)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+
+       if (dcc && dcc->f2fs_issue_discard) {
+               struct task_struct *discard_thread = dcc->f2fs_issue_discard;
+
+               dcc->f2fs_issue_discard = NULL;
+               kthread_stop(discard_thread);
+       }
+}
+
+/* This comes from f2fs_put_super */
+bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       struct discard_policy dpolicy;
+       bool dropped;
+
+       init_discard_policy(&dpolicy, DPOLICY_UMOUNT, dcc->discard_granularity);
+       __issue_discard_cmd(sbi, &dpolicy);
+       dropped = __drop_discard_cmd(sbi);
+       __wait_all_discard_cmd(sbi, &dpolicy);
+
+       return dropped;
+}
+
+static int issue_discard_thread(void *data)
+{
+       struct f2fs_sb_info *sbi = data;
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+       wait_queue_head_t *q = &dcc->discard_wait_queue;
+       struct discard_policy dpolicy;
+       unsigned int wait_ms = DEF_MIN_DISCARD_ISSUE_TIME;
+       int issued;
+
+       set_freezable();
+
+       do {
+               init_discard_policy(&dpolicy, DPOLICY_BG,
+                                       dcc->discard_granularity);
+
+               wait_event_interruptible_timeout(*q,
+                               kthread_should_stop() || freezing(current) ||
+                               dcc->discard_wake,
+                               msecs_to_jiffies(wait_ms));
+               if (try_to_freeze())
+                       continue;
+               if (f2fs_readonly(sbi->sb))
+                       continue;
+               if (kthread_should_stop())
+                       return 0;
+               if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
+                       wait_ms = dpolicy.max_interval;
+                       continue;
+               }
+
+               if (dcc->discard_wake)
+                       dcc->discard_wake = 0;
+
+               down_read(&GC_I(sbi)->gc_rwsem);
+               if (GC_I(sbi)->f2fs_gc_task && GC_I(sbi)->gc_urgent)
+                       init_discard_policy(&dpolicy, DPOLICY_FORCE, 1);
+               up_read(&GC_I(sbi)->gc_rwsem);
+
+               sb_start_intwrite(sbi->sb);
+
+               issued = __issue_discard_cmd(sbi, &dpolicy);
+               if (issued > 0) {
+                       __wait_all_discard_cmd(sbi, &dpolicy);
+                       wait_ms = dpolicy.min_interval;
+               } else if (issued == -1) {
+                       wait_ms = dpolicy.mid_interval;
+               } else {
+                       wait_ms = dpolicy.max_interval;
+               }
+
+               sb_end_intwrite(sbi->sb);
+
+       } while (!kthread_should_stop());
+       return 0;
+}
+
+#ifdef CONFIG_BLK_DEV_ZONED
+static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
+               struct block_device *bdev, block_t blkstart, block_t blklen)
+{
+       sector_t sector, nr_sects;
+       block_t lblkstart = blkstart;
+       int devi = 0;
+
+       if (sbi->s_ndevs) {
+               devi = f2fs_target_device_index(sbi, blkstart);
+               blkstart -= FDEV(devi).start_blk;
+       }
+
+       /*
+        * We need to know the type of the zone: for conventional zones,
+        * use regular discard if the drive supports it. For sequential
+        * zones, reset the zone write pointer.
+        */
+       switch (get_blkz_type(sbi, bdev, blkstart)) {
+
+       case BLK_ZONE_TYPE_CONVENTIONAL:
+               if (!blk_queue_discard(bdev_get_queue(bdev)))
+                       return 0;
+               return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
+       case BLK_ZONE_TYPE_SEQWRITE_REQ:
+       case BLK_ZONE_TYPE_SEQWRITE_PREF:
+               sector = SECTOR_FROM_BLOCK(blkstart);
+               nr_sects = SECTOR_FROM_BLOCK(blklen);
+
+               if (sector & (bdev_zone_sectors(bdev) - 1) ||
+                               nr_sects != bdev_zone_sectors(bdev)) {
+                       f2fs_msg(sbi->sb, KERN_INFO,
+                               "(%d) %s: Unaligned discard attempted (block %x 
+ %x)",
+                               devi, sbi->s_ndevs ? FDEV(devi).path : "",
+                               blkstart, blklen);
+                       return -EIO;
+               }
+               trace_f2fs_issue_reset_zone(bdev, blkstart);
+               return blkdev_reset_zones(bdev, sector,
+                                         nr_sects, GFP_NOFS);
+       default:
+               /* Unknown zone type: broken device ? */
+               return -EIO;
+       }
+}
+#endif
+
+static int __issue_discard_async(struct f2fs_sb_info *sbi,
+               struct block_device *bdev, block_t blkstart, block_t blklen)
+{
+#ifdef CONFIG_BLK_DEV_ZONED
+       if (f2fs_sb_has_blkzoned(sbi->sb) &&
+                               bdev_zoned_model(bdev) != BLK_ZONED_NONE)
+               return __f2fs_issue_discard_zone(sbi, bdev, blkstart, blklen);
+#endif
+       return __queue_discard_cmd(sbi, bdev, blkstart, blklen);
+}
+
+int f2fs_issue_discard(struct f2fs_sb_info *sbi,
+                               block_t blkstart, block_t blklen)
+{
+       sector_t start = blkstart, len = 0;
+       struct block_device *bdev;
+       struct seg_entry *se;
+       unsigned int offset;
+       block_t i;
+       int err = 0;
+
+       bdev = f2fs_target_device(sbi, blkstart, NULL);
+
+       for (i = blkstart; i < blkstart + blklen; i++, len++) {
+               if (i != start) {
+                       struct block_device *bdev2 =
+                               f2fs_target_device(sbi, i, NULL);
+
+                       if (bdev2 != bdev) {
+                               err = __issue_discard_async(sbi, bdev,
+                                               start, len);
+                               if (err)
+                                       return err;
+                               bdev = bdev2;
+                               start = i;
+                               len = 0;
+                       }
+               }
+
+               se = get_seg_entry(sbi, GET_SEGNO(sbi, i));
+               offset = GET_BLKOFF_FROM_SEG0(sbi, i);
+
+               if (!f2fs_test_and_set_bit(offset, se->discard_map))
+                       sbi->discard_blks--;
+       }
+
+       if (len)
+               err = __issue_discard_async(sbi, bdev, start, len);
+       return err;
+}
+
+bool add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc,
+                                                       bool check_only)
+{
+       int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long);
+       int max_blocks = sbi->blocks_per_seg;
+       struct seg_entry *se = get_seg_entry(sbi, cpc->trim_start);
+       unsigned long *cur_map = (unsigned long *)se->cur_valid_map;
+       unsigned long *ckpt_map = (unsigned long *)se->ckpt_valid_map;
+       unsigned long *discard_map = (unsigned long *)se->discard_map;
+       unsigned long *dmap = SIT_I(sbi)->tmp_map;
+       unsigned int start = 0, end = -1;
+       bool force = (cpc->reason & CP_DISCARD);
+       struct discard_entry *de = NULL;
+       struct list_head *head = &SM_I(sbi)->dcc_info->entry_list;
+       int i;
+
+       if (se->valid_blocks == max_blocks || !f2fs_discard_en(sbi))
+               return false;
+
+       if (!force) {
+               if (!test_opt(sbi, DISCARD) || !se->valid_blocks ||
+                       SM_I(sbi)->dcc_info->nr_discards >=
+                               SM_I(sbi)->dcc_info->max_discards)
+                       return false;
+       }
+
+       /* SIT_VBLOCK_MAP_SIZE should be multiple of sizeof(unsigned long) */
+       for (i = 0; i < entries; i++)
+               dmap[i] = force ? ~ckpt_map[i] & ~discard_map[i] :
+                               (cur_map[i] ^ ckpt_map[i]) & ckpt_map[i];
+
+       while (force || SM_I(sbi)->dcc_info->nr_discards <=
+                               SM_I(sbi)->dcc_info->max_discards) {
+               start = __find_rev_next_bit(dmap, max_blocks, end + 1);
+               if (start >= max_blocks)
+                       break;
+
+               end = __find_rev_next_zero_bit(dmap, max_blocks, start + 1);
+               if (force && start && end != max_blocks
+                                       && (end - start) < cpc->trim_minlen)
+                       continue;
+
+               if (check_only)
+                       return true;
+
+               if (!de) {
+                       de = f2fs_kmem_cache_alloc(discard_entry_slab,
+                                                               GFP_F2FS_ZERO);
+                       de->start_blkaddr = START_BLOCK(sbi, cpc->trim_start);
+                       list_add_tail(&de->list, head);
+               }
+
+               for (i = start; i < end; i++)
+                       __set_bit_le(i, (void *)de->discard_map);
+
+               SM_I(sbi)->dcc_info->nr_discards += end - start;
+       }
+       return false;
+}
+
+void release_discard_addr(struct discard_entry *entry)
+{
+       list_del(&entry->list);
+       kmem_cache_free(discard_entry_slab, entry);
+}
+
+void release_discard_addrs(struct f2fs_sb_info *sbi)
+{
+       struct list_head *head = &(SM_I(sbi)->dcc_info->entry_list);
+       struct discard_entry *entry, *this;
+
+       /* drop caches */
+       list_for_each_entry_safe(entry, this, head, list) {
+               list_del(&entry->list);
+               kmem_cache_free(discard_entry_slab, entry);
+       }
+}
+
+void init_discard_policy(struct discard_policy *dpolicy,
+                               int discard_type, unsigned int granularity)
+{
+       /* common policy */
+       dpolicy->type = discard_type;
+       dpolicy->sync = true;
+       dpolicy->granularity = granularity;
+
+       dpolicy->max_requests = DEF_MAX_DISCARD_REQUEST;
+       dpolicy->io_aware_gran = MAX_PLIST_NUM;
+
+       if (discard_type == DPOLICY_BG) {
+               dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
+               dpolicy->mid_interval = DEF_MID_DISCARD_ISSUE_TIME;
+               dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
+               dpolicy->io_aware = true;
+               dpolicy->sync = false;
+       } else if (discard_type == DPOLICY_FORCE) {
+               dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
+               dpolicy->mid_interval = DEF_MID_DISCARD_ISSUE_TIME;
+               dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
+               dpolicy->io_aware = false;
+       } else if (discard_type == DPOLICY_FSTRIM) {
+               dpolicy->io_aware = false;
+       } else if (discard_type == DPOLICY_UMOUNT) {
+               dpolicy->max_requests = UINT_MAX;
+               dpolicy->io_aware = false;
+       }
+}
+
+int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
+{
+       __u64 start = F2FS_BYTES_TO_BLK(range->start);
+       __u64 end = start + F2FS_BYTES_TO_BLK(range->len) - 1;
+       unsigned int start_segno, end_segno;
+       block_t start_block, end_block;
+       struct cp_control cpc;
+       struct discard_policy dpolicy;
+       unsigned long long trimmed = 0;
+       int err = 0;
+
+       if (start >= MAX_BLKADDR(sbi) || range->len < sbi->blocksize)
+               return -EINVAL;
+
+       if (end <= MAIN_BLKADDR(sbi))
+               return -EINVAL;
+
+       if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
+               f2fs_msg(sbi->sb, KERN_WARNING,
+                       "Found FS corruption, run fsck to fix.");
+               return -EIO;
+       }
+
+       /* start/end segment number in main_area */
+       start_segno = (start <= MAIN_BLKADDR(sbi)) ? 0 : GET_SEGNO(sbi, start);
+       end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :
+                                               GET_SEGNO(sbi, end);
+
+       cpc.reason = CP_DISCARD;
+       cpc.trim_minlen = max_t(__u64, 1, F2FS_BYTES_TO_BLK(range->minlen));
+       cpc.trim_start = start_segno;
+       cpc.trim_end = end_segno;
+
+       if (sbi->discard_blks == 0)
+               goto out;
+
+       mutex_lock(&sbi->gc_mutex);
+       err = write_checkpoint(sbi, &cpc);
+       mutex_unlock(&sbi->gc_mutex);
+       if (err)
+               goto out;
+
+       start_block = START_BLOCK(sbi, start_segno);
+       end_block = START_BLOCK(sbi, end_segno + 1);
+
+       init_discard_policy(&dpolicy, DPOLICY_FSTRIM, cpc.trim_minlen);
+       __issue_discard_cmd_range(sbi, &dpolicy, start_block, end_block);
+       trimmed = __wait_discard_cmd_range(sbi, &dpolicy,
+                                       start_block, end_block);
+out:
+       range->len = F2FS_BLK_TO_BYTES(trimmed);
+       return err;
+}
+
+int create_discard_cmd_control(struct f2fs_sb_info *sbi)
+{
+       dev_t dev = sbi->sb->s_bdev->bd_dev;
+       struct discard_cmd_control *dcc;
+       int err = 0, i;
+
+       if (SM_I(sbi)->dcc_info) {
+               dcc = SM_I(sbi)->dcc_info;
+               goto init_thread;
+       }
+
+       dcc = f2fs_kzalloc(sbi, sizeof(struct discard_cmd_control), GFP_KERNEL);
+       if (!dcc)
+               return -ENOMEM;
+
+       dcc->discard_granularity = DEFAULT_DISCARD_GRANULARITY;
+       INIT_LIST_HEAD(&dcc->entry_list);
+       for (i = 0; i < MAX_PLIST_NUM; i++)
+               INIT_LIST_HEAD(&dcc->pend_list[i]);
+       INIT_LIST_HEAD(&dcc->wait_list);
+       INIT_LIST_HEAD(&dcc->fstrim_list);
+       mutex_init(&dcc->cmd_lock);
+       atomic_set(&dcc->issued_discard, 0);
+       atomic_set(&dcc->issing_discard, 0);
+       atomic_set(&dcc->discard_cmd_cnt, 0);
+       dcc->nr_discards = 0;
+       dcc->max_discards = MAIN_SEGS(sbi) << sbi->log_blocks_per_seg;
+       dcc->undiscard_blks = 0;
+       dcc->root = RB_ROOT;
+
+       init_waitqueue_head(&dcc->discard_wait_queue);
+       SM_I(sbi)->dcc_info = dcc;
+init_thread:
+       dcc->f2fs_issue_discard = kthread_run(issue_discard_thread, sbi,
+                               "f2fs_discard-%u:%u", MAJOR(dev), MINOR(dev));
+       if (IS_ERR(dcc->f2fs_issue_discard)) {
+               err = PTR_ERR(dcc->f2fs_issue_discard);
+               kfree(dcc);
+               SM_I(sbi)->dcc_info = NULL;
+               return err;
+       }
+
+       return err;
+}
+
+void destroy_discard_cmd_control(struct f2fs_sb_info *sbi)
+{
+       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+
+       if (!dcc)
+               return;
+
+       stop_discard_thread(sbi);
+
+       kfree(dcc);
+       SM_I(sbi)->dcc_info = NULL;
+}
+
+int __init create_discard_caches(void)
+{
+       discard_entry_slab = f2fs_kmem_cache_create("discard_entry",
+                       sizeof(struct discard_entry));
+       if (!discard_entry_slab)
+               goto fail;
+
+       discard_cmd_slab = f2fs_kmem_cache_create("discard_cmd",
+                       sizeof(struct discard_cmd));
+       if (!discard_cmd_slab)
+               goto destroy_discard_entry;
+       return 0;
+destroy_discard_entry:
+       kmem_cache_destroy(discard_entry_slab);
+fail:
+       return -ENOMEM;
+}
+
+void destroy_discard_caches(void)
+{
+       kmem_cache_destroy(discard_cmd_slab);
+       kmem_cache_destroy(discard_entry_slab);
+}
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c8d6d27384f1..64e3677998d8 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2803,6 +2803,10 @@ void destroy_node_manager_caches(void);
 /*
  * segment.c
  */
+unsigned long __find_rev_next_bit(const unsigned long *addr,
+                               unsigned long size, unsigned long offset);
+unsigned long __find_rev_next_zero_bit(const unsigned long *addr,
+                       unsigned long size, unsigned long offset);
 bool need_SSR(struct f2fs_sb_info *sbi);
 void register_inmem_page(struct inode *inode, struct page *page);
 void drop_inmem_pages_all(struct f2fs_sb_info *sbi);
@@ -2817,16 +2821,9 @@ int f2fs_flush_device_cache(struct f2fs_sb_info *sbi);
 void destroy_flush_cmd_control(struct f2fs_sb_info *sbi, bool free);
 void invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr);
 bool is_checkpointed_data(struct f2fs_sb_info *sbi, block_t blkaddr);
-void init_discard_policy(struct discard_policy *dpolicy, int discard_type,
-                                               unsigned int granularity);
-void drop_discard_cmd(struct f2fs_sb_info *sbi);
-void stop_discard_thread(struct f2fs_sb_info *sbi);
-bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi);
 void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc);
-void release_discard_addrs(struct f2fs_sb_info *sbi);
 int npages_for_summary_flush(struct f2fs_sb_info *sbi, bool for_ra);
 void allocate_new_segments(struct f2fs_sb_info *sbi);
-int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range);
 bool exist_trim_candidates(struct f2fs_sb_info *sbi, struct cp_control *cpc);
 struct page *get_sum_page(struct f2fs_sb_info *sbi, unsigned int segno);
 void update_meta_page(struct f2fs_sb_info *sbi, void *src, block_t blk_addr);
@@ -2856,8 +2853,6 @@ int lookup_journal_in_cursum(struct f2fs_journal 
*journal, int type,
 void flush_sit_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc);
 int build_segment_manager(struct f2fs_sb_info *sbi);
 void destroy_segment_manager(struct f2fs_sb_info *sbi);
-int __init create_discard_caches(void);
-void destroy_discard_caches(void);
 int __init create_segment_manager_caches(void);
 void destroy_segment_manager_caches(void);
 int rw_hint_to_seg_type(enum rw_hint hint);
@@ -3246,6 +3241,27 @@ void f2fs_exit_sysfs(void);
 int f2fs_register_sysfs(struct f2fs_sb_info *sbi);
 void f2fs_unregister_sysfs(struct f2fs_sb_info *sbi);
 
+/*
+ * discard.c
+ */
+void init_discard_policy(struct discard_policy *dpolicy, int discard_type,
+                                               unsigned int granularity);
+void drop_discard_cmd(struct f2fs_sb_info *sbi);
+void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr);
+void stop_discard_thread(struct f2fs_sb_info *sbi);
+bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi);
+int f2fs_issue_discard(struct f2fs_sb_info *sbi,
+                               block_t blkstart, block_t blklen);
+bool add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc,
+                                                       bool check_only);
+void release_discard_addr(struct discard_entry *entry);
+void release_discard_addrs(struct f2fs_sb_info *sbi);
+int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range);
+int create_discard_cmd_control(struct f2fs_sb_info *sbi);
+void destroy_discard_cmd_control(struct f2fs_sb_info *sbi);
+int __init create_discard_caches(void);
+void destroy_discard_caches(void);
+
 /*
  * crypto support
  */
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 187f957747be..f85a537100d7 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -28,8 +28,6 @@
 
 #define __reverse_ffz(x) __reverse_ffs(~(x))
 
-static struct kmem_cache *discard_entry_slab;
-static struct kmem_cache *discard_cmd_slab;
 static struct kmem_cache *sit_entry_set_slab;
 static struct kmem_cache *inmem_entry_slab;
 
@@ -96,7 +94,7 @@ static inline unsigned long __reverse_ffs(unsigned long word)
  *   f2fs_set_bit(0, bitmap) => 1000 0000
  *   f2fs_set_bit(7, bitmap) => 0000 0001
  */
-static unsigned long __find_rev_next_bit(const unsigned long *addr,
+unsigned long __find_rev_next_bit(const unsigned long *addr,
                        unsigned long size, unsigned long offset)
 {
        const unsigned long *p = addr + BIT_WORD(offset);
@@ -132,7 +130,7 @@ static unsigned long __find_rev_next_bit(const unsigned 
long *addr,
        return result - size + __reverse_ffs(tmp);
 }
 
-static unsigned long __find_rev_next_zero_bit(const unsigned long *addr,
+unsigned long __find_rev_next_zero_bit(const unsigned long *addr,
                        unsigned long size, unsigned long offset)
 {
        const unsigned long *p = addr + BIT_WORD(offset);
@@ -806,825 +804,6 @@ static void locate_dirty_segment(struct f2fs_sb_info 
*sbi, unsigned int segno)
        mutex_unlock(&dirty_i->seglist_lock);
 }
 
-static struct discard_cmd *__create_discard_cmd(struct f2fs_sb_info *sbi,
-               struct block_device *bdev, block_t lstart,
-               block_t start, block_t len)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       struct list_head *pend_list;
-       struct discard_cmd *dc;
-
-       f2fs_bug_on(sbi, !len);
-
-       pend_list = &dcc->pend_list[plist_idx(len)];
-
-       dc = f2fs_kmem_cache_alloc(discard_cmd_slab, GFP_NOFS);
-       INIT_LIST_HEAD(&dc->list);
-       dc->bdev = bdev;
-       dc->lstart = lstart;
-       dc->start = start;
-       dc->len = len;
-       dc->ref = 0;
-       dc->state = D_PREP;
-       dc->error = 0;
-       init_completion(&dc->wait);
-       list_add_tail(&dc->list, pend_list);
-       atomic_inc(&dcc->discard_cmd_cnt);
-       dcc->undiscard_blks += len;
-
-       return dc;
-}
-
-static struct discard_cmd *__attach_discard_cmd(struct f2fs_sb_info *sbi,
-                               struct block_device *bdev, block_t lstart,
-                               block_t start, block_t len,
-                               struct rb_node *parent, struct rb_node **p)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       struct discard_cmd *dc;
-
-       dc = __create_discard_cmd(sbi, bdev, lstart, start, len);
-
-       rb_link_node(&dc->rb_node, parent, p);
-       rb_insert_color(&dc->rb_node, &dcc->root);
-
-       return dc;
-}
-
-static void __detach_discard_cmd(struct discard_cmd_control *dcc,
-                                                       struct discard_cmd *dc)
-{
-       if (dc->state == D_DONE)
-               atomic_dec(&dcc->issing_discard);
-
-       list_del(&dc->list);
-       rb_erase(&dc->rb_node, &dcc->root);
-       dcc->undiscard_blks -= dc->len;
-
-       kmem_cache_free(discard_cmd_slab, dc);
-
-       atomic_dec(&dcc->discard_cmd_cnt);
-}
-
-static void __remove_discard_cmd(struct f2fs_sb_info *sbi,
-                                                       struct discard_cmd *dc)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-
-       trace_f2fs_remove_discard(dc->bdev, dc->start, dc->len);
-
-       f2fs_bug_on(sbi, dc->ref);
-
-       if (dc->error == -EOPNOTSUPP)
-               dc->error = 0;
-
-       if (dc->error)
-               f2fs_msg(sbi->sb, KERN_INFO,
-                       "Issue discard(%u, %u, %u) failed, ret: %d",
-                       dc->lstart, dc->start, dc->len, dc->error);
-       __detach_discard_cmd(dcc, dc);
-}
-
-static void f2fs_submit_discard_endio(struct bio *bio)
-{
-       struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
-
-       dc->error = blk_status_to_errno(bio->bi_status);
-       dc->state = D_DONE;
-       complete_all(&dc->wait);
-       bio_put(bio);
-}
-
-static void __check_sit_bitmap(struct f2fs_sb_info *sbi,
-                               block_t start, block_t end)
-{
-#ifdef CONFIG_F2FS_CHECK_FS
-       struct seg_entry *sentry;
-       unsigned int segno;
-       block_t blk = start;
-       unsigned long offset, size, max_blocks = sbi->blocks_per_seg;
-       unsigned long *map;
-
-       while (blk < end) {
-               segno = GET_SEGNO(sbi, blk);
-               sentry = get_seg_entry(sbi, segno);
-               offset = GET_BLKOFF_FROM_SEG0(sbi, blk);
-
-               if (end < START_BLOCK(sbi, segno + 1))
-                       size = GET_BLKOFF_FROM_SEG0(sbi, end);
-               else
-                       size = max_blocks;
-               map = (unsigned long *)(sentry->cur_valid_map);
-               offset = __find_rev_next_bit(map, size, offset);
-               f2fs_bug_on(sbi, offset != size);
-               blk = START_BLOCK(sbi, segno + 1);
-       }
-#endif
-}
-
-/* this function is copied from blkdev_issue_discard from block/blk-lib.c */
-static void __submit_discard_cmd(struct f2fs_sb_info *sbi,
-                                               struct discard_policy *dpolicy,
-                                               struct discard_cmd *dc)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
-                                       &(dcc->fstrim_list) : &(dcc->wait_list);
-       struct bio *bio = NULL;
-       int flag = dpolicy->sync ? REQ_SYNC : 0;
-
-       if (dc->state != D_PREP)
-               return;
-
-       if (is_sbi_flag_set(sbi, SBI_NEED_FSCK))
-               return;
-
-       trace_f2fs_issue_discard(dc->bdev, dc->start, dc->len);
-
-       dc->error = __blkdev_issue_discard(dc->bdev,
-                               SECTOR_FROM_BLOCK(dc->start),
-                               SECTOR_FROM_BLOCK(dc->len),
-                               GFP_NOFS, 0, &bio);
-       if (!dc->error) {
-               /* should keep before submission to avoid D_DONE right away */
-               dc->state = D_SUBMIT;
-               atomic_inc(&dcc->issued_discard);
-               atomic_inc(&dcc->issing_discard);
-               if (bio) {
-                       bio->bi_private = dc;
-                       bio->bi_end_io = f2fs_submit_discard_endio;
-                       bio->bi_opf |= flag;
-                       submit_bio(bio);
-                       list_move_tail(&dc->list, wait_list);
-                       __check_sit_bitmap(sbi, dc->start, dc->start + dc->len);
-
-                       f2fs_update_iostat(sbi, FS_DISCARD, 1);
-               }
-       } else {
-               __remove_discard_cmd(sbi, dc);
-       }
-}
-
-static struct discard_cmd *__insert_discard_tree(struct f2fs_sb_info *sbi,
-                               struct block_device *bdev, block_t lstart,
-                               block_t start, block_t len,
-                               struct rb_node **insert_p,
-                               struct rb_node *insert_parent)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       struct rb_node **p;
-       struct rb_node *parent = NULL;
-       struct discard_cmd *dc = NULL;
-
-       if (insert_p && insert_parent) {
-               parent = insert_parent;
-               p = insert_p;
-               goto do_insert;
-       }
-
-       p = __lookup_rb_tree_for_insert(sbi, &dcc->root, &parent, lstart);
-do_insert:
-       dc = __attach_discard_cmd(sbi, bdev, lstart, start, len, parent, p);
-       if (!dc)
-               return NULL;
-
-       return dc;
-}
-
-static void __relocate_discard_cmd(struct discard_cmd_control *dcc,
-                                               struct discard_cmd *dc)
-{
-       list_move_tail(&dc->list, &dcc->pend_list[plist_idx(dc->len)]);
-}
-
-static void __punch_discard_cmd(struct f2fs_sb_info *sbi,
-                               struct discard_cmd *dc, block_t blkaddr)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       struct discard_info di = dc->di;
-       bool modified = false;
-
-       if (dc->state == D_DONE || dc->len == 1) {
-               __remove_discard_cmd(sbi, dc);
-               return;
-       }
-
-       dcc->undiscard_blks -= di.len;
-
-       if (blkaddr > di.lstart) {
-               dc->len = blkaddr - dc->lstart;
-               dcc->undiscard_blks += dc->len;
-               __relocate_discard_cmd(dcc, dc);
-               modified = true;
-       }
-
-       if (blkaddr < di.lstart + di.len - 1) {
-               if (modified) {
-                       __insert_discard_tree(sbi, dc->bdev, blkaddr + 1,
-                                       di.start + blkaddr + 1 - di.lstart,
-                                       di.lstart + di.len - 1 - blkaddr,
-                                       NULL, NULL);
-               } else {
-                       dc->lstart++;
-                       dc->len--;
-                       dc->start++;
-                       dcc->undiscard_blks += dc->len;
-                       __relocate_discard_cmd(dcc, dc);
-               }
-       }
-}
-
-static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
-                               struct block_device *bdev, block_t lstart,
-                               block_t start, block_t len)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
-       struct discard_cmd *dc;
-       struct discard_info di = {0};
-       struct rb_node **insert_p = NULL, *insert_parent = NULL;
-       block_t end = lstart + len;
-
-       mutex_lock(&dcc->cmd_lock);
-
-       dc = (struct discard_cmd *)__lookup_rb_tree_ret(&dcc->root,
-                                       NULL, lstart,
-                                       (struct rb_entry **)&prev_dc,
-                                       (struct rb_entry **)&next_dc,
-                                       &insert_p, &insert_parent, true);
-       if (dc)
-               prev_dc = dc;
-
-       if (!prev_dc) {
-               di.lstart = lstart;
-               di.len = next_dc ? next_dc->lstart - lstart : len;
-               di.len = min(di.len, len);
-               di.start = start;
-       }
-
-       while (1) {
-               struct rb_node *node;
-               bool merged = false;
-               struct discard_cmd *tdc = NULL;
-
-               if (prev_dc) {
-                       di.lstart = prev_dc->lstart + prev_dc->len;
-                       if (di.lstart < lstart)
-                               di.lstart = lstart;
-                       if (di.lstart >= end)
-                               break;
-
-                       if (!next_dc || next_dc->lstart > end)
-                               di.len = end - di.lstart;
-                       else
-                               di.len = next_dc->lstart - di.lstart;
-                       di.start = start + di.lstart - lstart;
-               }
-
-               if (!di.len)
-                       goto next;
-
-               if (prev_dc && prev_dc->state == D_PREP &&
-                       prev_dc->bdev == bdev &&
-                       __is_discard_back_mergeable(&di, &prev_dc->di)) {
-                       prev_dc->di.len += di.len;
-                       dcc->undiscard_blks += di.len;
-                       __relocate_discard_cmd(dcc, prev_dc);
-                       di = prev_dc->di;
-                       tdc = prev_dc;
-                       merged = true;
-               }
-
-               if (next_dc && next_dc->state == D_PREP &&
-                       next_dc->bdev == bdev &&
-                       __is_discard_front_mergeable(&di, &next_dc->di)) {
-                       next_dc->di.lstart = di.lstart;
-                       next_dc->di.len += di.len;
-                       next_dc->di.start = di.start;
-                       dcc->undiscard_blks += di.len;
-                       __relocate_discard_cmd(dcc, next_dc);
-                       if (tdc)
-                               __remove_discard_cmd(sbi, tdc);
-                       merged = true;
-               }
-
-               if (!merged) {
-                       __insert_discard_tree(sbi, bdev, di.lstart, di.start,
-                                                       di.len, NULL, NULL);
-               }
- next:
-               prev_dc = next_dc;
-               if (!prev_dc)
-                       break;
-
-               node = rb_next(&prev_dc->rb_node);
-               next_dc = rb_entry_safe(node, struct discard_cmd, rb_node);
-       }
-
-       mutex_unlock(&dcc->cmd_lock);
-}
-
-static int __queue_discard_cmd(struct f2fs_sb_info *sbi,
-               struct block_device *bdev, block_t blkstart, block_t blklen)
-{
-       block_t lblkstart = blkstart;
-
-       trace_f2fs_queue_discard(bdev, blkstart, blklen);
-
-       if (sbi->s_ndevs) {
-               int devi = f2fs_target_device_index(sbi, blkstart);
-
-               blkstart -= FDEV(devi).start_blk;
-       }
-       __update_discard_tree_range(sbi, bdev, lblkstart, blkstart, blklen);
-       return 0;
-}
-
-static void __issue_discard_cmd_range(struct f2fs_sb_info *sbi,
-                                       struct discard_policy *dpolicy,
-                                       unsigned int start, unsigned int end)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
-       struct rb_node **insert_p = NULL, *insert_parent = NULL;
-       struct discard_cmd *dc;
-       struct blk_plug plug;
-       int issued;
-
-next:
-       issued = 0;
-
-       mutex_lock(&dcc->cmd_lock);
-       f2fs_bug_on(sbi, !__check_rb_tree_consistence(sbi, &dcc->root));
-
-       dc = (struct discard_cmd *)__lookup_rb_tree_ret(&dcc->root,
-                                       NULL, start,
-                                       (struct rb_entry **)&prev_dc,
-                                       (struct rb_entry **)&next_dc,
-                                       &insert_p, &insert_parent, true);
-       if (!dc)
-               dc = next_dc;
-
-       blk_start_plug(&plug);
-
-       while (dc && dc->lstart <= end) {
-               struct rb_node *node;
-
-               if (dc->len < dpolicy->granularity)
-                       goto skip;
-
-               if (dc->state != D_PREP) {
-                       list_move_tail(&dc->list, &dcc->fstrim_list);
-                       goto skip;
-               }
-
-               __submit_discard_cmd(sbi, dpolicy, dc);
-
-               if (++issued >= dpolicy->max_requests) {
-                       start = dc->lstart + dc->len;
-
-                       blk_finish_plug(&plug);
-                       mutex_unlock(&dcc->cmd_lock);
-
-                       schedule();
-
-                       goto next;
-               }
-skip:
-               node = rb_next(&dc->rb_node);
-               dc = rb_entry_safe(node, struct discard_cmd, rb_node);
-
-               if (fatal_signal_pending(current))
-                       break;
-       }
-
-       blk_finish_plug(&plug);
-       mutex_unlock(&dcc->cmd_lock);
-}
-
-static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
-                                       struct discard_policy *dpolicy)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       struct list_head *pend_list;
-       struct discard_cmd *dc, *tmp;
-       struct blk_plug plug;
-       int i, iter = 0, issued = 0;
-       bool io_interrupted = false;
-
-       for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
-               if (i + 1 < dpolicy->granularity)
-                       break;
-               pend_list = &dcc->pend_list[i];
-
-               mutex_lock(&dcc->cmd_lock);
-               if (list_empty(pend_list))
-                       goto next;
-               f2fs_bug_on(sbi, !__check_rb_tree_consistence(sbi, &dcc->root));
-               blk_start_plug(&plug);
-               list_for_each_entry_safe(dc, tmp, pend_list, list) {
-                       f2fs_bug_on(sbi, dc->state != D_PREP);
-
-                       if (dpolicy->io_aware && i < dpolicy->io_aware_gran &&
-                                                               !is_idle(sbi)) {
-                               io_interrupted = true;
-                               goto skip;
-                       }
-
-                       __submit_discard_cmd(sbi, dpolicy, dc);
-                       issued++;
-skip:
-                       if (++iter >= dpolicy->max_requests)
-                               break;
-               }
-               blk_finish_plug(&plug);
-next:
-               mutex_unlock(&dcc->cmd_lock);
-
-               if (iter >= dpolicy->max_requests)
-                       break;
-       }
-
-       if (!issued && io_interrupted)
-               issued = -1;
-
-       return issued;
-}
-
-static bool __drop_discard_cmd(struct f2fs_sb_info *sbi)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       struct list_head *pend_list;
-       struct discard_cmd *dc, *tmp;
-       int i;
-       bool dropped = false;
-
-       mutex_lock(&dcc->cmd_lock);
-       for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
-               pend_list = &dcc->pend_list[i];
-               list_for_each_entry_safe(dc, tmp, pend_list, list) {
-                       f2fs_bug_on(sbi, dc->state != D_PREP);
-                       __remove_discard_cmd(sbi, dc);
-                       dropped = true;
-               }
-       }
-       mutex_unlock(&dcc->cmd_lock);
-
-       return dropped;
-}
-
-void drop_discard_cmd(struct f2fs_sb_info *sbi)
-{
-       __drop_discard_cmd(sbi);
-}
-
-static unsigned int __wait_one_discard_bio(struct f2fs_sb_info *sbi,
-                                                       struct discard_cmd *dc)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       unsigned int len = 0;
-
-       wait_for_completion_io(&dc->wait);
-       mutex_lock(&dcc->cmd_lock);
-       f2fs_bug_on(sbi, dc->state != D_DONE);
-       dc->ref--;
-       if (!dc->ref) {
-               if (!dc->error)
-                       len = dc->len;
-               __remove_discard_cmd(sbi, dc);
-       }
-       mutex_unlock(&dcc->cmd_lock);
-
-       return len;
-}
-
-static unsigned int __wait_discard_cmd_range(struct f2fs_sb_info *sbi,
-                                               struct discard_policy *dpolicy,
-                                               block_t start, block_t end)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
-                                       &(dcc->fstrim_list) : &(dcc->wait_list);
-       struct discard_cmd *dc, *tmp;
-       bool need_wait;
-       unsigned int trimmed = 0;
-
-next:
-       need_wait = false;
-
-       mutex_lock(&dcc->cmd_lock);
-       list_for_each_entry_safe(dc, tmp, wait_list, list) {
-               if (dc->lstart + dc->len <= start || end <= dc->lstart)
-                       continue;
-               if (dc->len < dpolicy->granularity)
-                       continue;
-               if (dc->state == D_DONE && !dc->ref) {
-                       wait_for_completion_io(&dc->wait);
-                       if (!dc->error)
-                               trimmed += dc->len;
-                       __remove_discard_cmd(sbi, dc);
-               } else {
-                       dc->ref++;
-                       need_wait = true;
-                       break;
-               }
-       }
-       mutex_unlock(&dcc->cmd_lock);
-
-       if (need_wait) {
-               trimmed += __wait_one_discard_bio(sbi, dc);
-               goto next;
-       }
-
-       return trimmed;
-}
-
-static void __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
-                                               struct discard_policy *dpolicy)
-{
-       __wait_discard_cmd_range(sbi, dpolicy, 0, UINT_MAX);
-}
-
-/* This should be covered by global mutex, &sit_i->sentry_lock */
-static void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       struct discard_cmd *dc;
-       bool need_wait = false;
-
-       mutex_lock(&dcc->cmd_lock);
-       dc = (struct discard_cmd *)__lookup_rb_tree(&dcc->root, NULL, blkaddr);
-       if (dc) {
-               if (dc->state == D_PREP) {
-                       __punch_discard_cmd(sbi, dc, blkaddr);
-               } else {
-                       dc->ref++;
-                       need_wait = true;
-               }
-       }
-       mutex_unlock(&dcc->cmd_lock);
-
-       if (need_wait)
-               __wait_one_discard_bio(sbi, dc);
-}
-
-void stop_discard_thread(struct f2fs_sb_info *sbi)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-
-       if (dcc && dcc->f2fs_issue_discard) {
-               struct task_struct *discard_thread = dcc->f2fs_issue_discard;
-
-               dcc->f2fs_issue_discard = NULL;
-               kthread_stop(discard_thread);
-       }
-}
-
-/* This comes from f2fs_put_super */
-bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       struct discard_policy dpolicy;
-       bool dropped;
-
-       init_discard_policy(&dpolicy, DPOLICY_UMOUNT, dcc->discard_granularity);
-       __issue_discard_cmd(sbi, &dpolicy);
-       dropped = __drop_discard_cmd(sbi);
-       __wait_all_discard_cmd(sbi, &dpolicy);
-
-       return dropped;
-}
-
-static int issue_discard_thread(void *data)
-{
-       struct f2fs_sb_info *sbi = data;
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-       wait_queue_head_t *q = &dcc->discard_wait_queue;
-       struct discard_policy dpolicy;
-       unsigned int wait_ms = DEF_MIN_DISCARD_ISSUE_TIME;
-       int issued;
-
-       set_freezable();
-
-       do {
-               init_discard_policy(&dpolicy, DPOLICY_BG,
-                                       dcc->discard_granularity);
-
-               wait_event_interruptible_timeout(*q,
-                               kthread_should_stop() || freezing(current) ||
-                               dcc->discard_wake,
-                               msecs_to_jiffies(wait_ms));
-               if (try_to_freeze())
-                       continue;
-               if (f2fs_readonly(sbi->sb))
-                       continue;
-               if (kthread_should_stop())
-                       return 0;
-               if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
-                       wait_ms = dpolicy.max_interval;
-                       continue;
-               }
-
-               if (dcc->discard_wake)
-                       dcc->discard_wake = 0;
-
-               down_read(&GC_I(sbi)->gc_rwsem);
-               if (GC_I(sbi)->f2fs_gc_task && GC_I(sbi)->gc_urgent)
-                       init_discard_policy(&dpolicy, DPOLICY_FORCE, 1);
-               up_read(&GC_I(sbi)->gc_rwsem);
-
-               sb_start_intwrite(sbi->sb);
-
-               issued = __issue_discard_cmd(sbi, &dpolicy);
-               if (issued > 0) {
-                       __wait_all_discard_cmd(sbi, &dpolicy);
-                       wait_ms = dpolicy.min_interval;
-               } else if (issued == -1){
-                       wait_ms = dpolicy.mid_interval;
-               } else {
-                       wait_ms = dpolicy.max_interval;
-               }
-
-               sb_end_intwrite(sbi->sb);
-
-       } while (!kthread_should_stop());
-       return 0;
-}
-
-#ifdef CONFIG_BLK_DEV_ZONED
-static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
-               struct block_device *bdev, block_t blkstart, block_t blklen)
-{
-       sector_t sector, nr_sects;
-       block_t lblkstart = blkstart;
-       int devi = 0;
-
-       if (sbi->s_ndevs) {
-               devi = f2fs_target_device_index(sbi, blkstart);
-               blkstart -= FDEV(devi).start_blk;
-       }
-
-       /*
-        * We need to know the type of the zone: for conventional zones,
-        * use regular discard if the drive supports it. For sequential
-        * zones, reset the zone write pointer.
-        */
-       switch (get_blkz_type(sbi, bdev, blkstart)) {
-
-       case BLK_ZONE_TYPE_CONVENTIONAL:
-               if (!blk_queue_discard(bdev_get_queue(bdev)))
-                       return 0;
-               return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
-       case BLK_ZONE_TYPE_SEQWRITE_REQ:
-       case BLK_ZONE_TYPE_SEQWRITE_PREF:
-               sector = SECTOR_FROM_BLOCK(blkstart);
-               nr_sects = SECTOR_FROM_BLOCK(blklen);
-
-               if (sector & (bdev_zone_sectors(bdev) - 1) ||
-                               nr_sects != bdev_zone_sectors(bdev)) {
-                       f2fs_msg(sbi->sb, KERN_INFO,
-                               "(%d) %s: Unaligned discard attempted (block %x 
+ %x)",
-                               devi, sbi->s_ndevs ? FDEV(devi).path: "",
-                               blkstart, blklen);
-                       return -EIO;
-               }
-               trace_f2fs_issue_reset_zone(bdev, blkstart);
-               return blkdev_reset_zones(bdev, sector,
-                                         nr_sects, GFP_NOFS);
-       default:
-               /* Unknown zone type: broken device ? */
-               return -EIO;
-       }
-}
-#endif
-
-static int __issue_discard_async(struct f2fs_sb_info *sbi,
-               struct block_device *bdev, block_t blkstart, block_t blklen)
-{
-#ifdef CONFIG_BLK_DEV_ZONED
-       if (f2fs_sb_has_blkzoned(sbi->sb) &&
-                               bdev_zoned_model(bdev) != BLK_ZONED_NONE)
-               return __f2fs_issue_discard_zone(sbi, bdev, blkstart, blklen);
-#endif
-       return __queue_discard_cmd(sbi, bdev, blkstart, blklen);
-}
-
-static int f2fs_issue_discard(struct f2fs_sb_info *sbi,
-                               block_t blkstart, block_t blklen)
-{
-       sector_t start = blkstart, len = 0;
-       struct block_device *bdev;
-       struct seg_entry *se;
-       unsigned int offset;
-       block_t i;
-       int err = 0;
-
-       bdev = f2fs_target_device(sbi, blkstart, NULL);
-
-       for (i = blkstart; i < blkstart + blklen; i++, len++) {
-               if (i != start) {
-                       struct block_device *bdev2 =
-                               f2fs_target_device(sbi, i, NULL);
-
-                       if (bdev2 != bdev) {
-                               err = __issue_discard_async(sbi, bdev,
-                                               start, len);
-                               if (err)
-                                       return err;
-                               bdev = bdev2;
-                               start = i;
-                               len = 0;
-                       }
-               }
-
-               se = get_seg_entry(sbi, GET_SEGNO(sbi, i));
-               offset = GET_BLKOFF_FROM_SEG0(sbi, i);
-
-               if (!f2fs_test_and_set_bit(offset, se->discard_map))
-                       sbi->discard_blks--;
-       }
-
-       if (len)
-               err = __issue_discard_async(sbi, bdev, start, len);
-       return err;
-}
-
-static bool add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc,
-                                                       bool check_only)
-{
-       int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long);
-       int max_blocks = sbi->blocks_per_seg;
-       struct seg_entry *se = get_seg_entry(sbi, cpc->trim_start);
-       unsigned long *cur_map = (unsigned long *)se->cur_valid_map;
-       unsigned long *ckpt_map = (unsigned long *)se->ckpt_valid_map;
-       unsigned long *discard_map = (unsigned long *)se->discard_map;
-       unsigned long *dmap = SIT_I(sbi)->tmp_map;
-       unsigned int start = 0, end = -1;
-       bool force = (cpc->reason & CP_DISCARD);
-       struct discard_entry *de = NULL;
-       struct list_head *head = &SM_I(sbi)->dcc_info->entry_list;
-       int i;
-
-       if (se->valid_blocks == max_blocks || !f2fs_discard_en(sbi))
-               return false;
-
-       if (!force) {
-               if (!test_opt(sbi, DISCARD) || !se->valid_blocks ||
-                       SM_I(sbi)->dcc_info->nr_discards >=
-                               SM_I(sbi)->dcc_info->max_discards)
-                       return false;
-       }
-
-       /* SIT_VBLOCK_MAP_SIZE should be multiple of sizeof(unsigned long) */
-       for (i = 0; i < entries; i++)
-               dmap[i] = force ? ~ckpt_map[i] & ~discard_map[i] :
-                               (cur_map[i] ^ ckpt_map[i]) & ckpt_map[i];
-
-       while (force || SM_I(sbi)->dcc_info->nr_discards <=
-                               SM_I(sbi)->dcc_info->max_discards) {
-               start = __find_rev_next_bit(dmap, max_blocks, end + 1);
-               if (start >= max_blocks)
-                       break;
-
-               end = __find_rev_next_zero_bit(dmap, max_blocks, start + 1);
-               if (force && start && end != max_blocks
-                                       && (end - start) < cpc->trim_minlen)
-                       continue;
-
-               if (check_only)
-                       return true;
-
-               if (!de) {
-                       de = f2fs_kmem_cache_alloc(discard_entry_slab,
-                                                               GFP_F2FS_ZERO);
-                       de->start_blkaddr = START_BLOCK(sbi, cpc->trim_start);
-                       list_add_tail(&de->list, head);
-               }
-
-               for (i = start; i < end; i++)
-                       __set_bit_le(i, (void *)de->discard_map);
-
-               SM_I(sbi)->dcc_info->nr_discards += end - start;
-       }
-       return false;
-}
-
-void release_discard_addr(struct discard_entry *entry)
-{
-       list_del(&entry->list);
-       kmem_cache_free(discard_entry_slab, entry);
-}
-
-void release_discard_addrs(struct f2fs_sb_info *sbi)
-{
-       struct list_head *head = &(SM_I(sbi)->dcc_info->entry_list);
-       struct discard_entry *entry, *this;
-
-       /* drop caches */
-       list_for_each_entry_safe(entry, this, head, list)
-               release_discard_addr(entry);
-}
-
 /*
  * Should call clear_prefree_segments after checkpoint is done.
  */
@@ -1729,94 +908,6 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, 
struct cp_control *cpc)
        wake_up_discard_thread(sbi, false);
 }
 
-void init_discard_policy(struct discard_policy *dpolicy,
-                               int discard_type, unsigned int granularity)
-{
-       /* common policy */
-       dpolicy->type = discard_type;
-       dpolicy->sync = true;
-       dpolicy->granularity = granularity;
-
-       dpolicy->max_requests = DEF_MAX_DISCARD_REQUEST;
-       dpolicy->io_aware_gran = MAX_PLIST_NUM;
-
-       if (discard_type == DPOLICY_BG) {
-               dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
-               dpolicy->mid_interval = DEF_MID_DISCARD_ISSUE_TIME;
-               dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
-               dpolicy->io_aware = true;
-               dpolicy->sync = false;
-       } else if (discard_type == DPOLICY_FORCE) {
-               dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
-               dpolicy->mid_interval = DEF_MID_DISCARD_ISSUE_TIME;
-               dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
-               dpolicy->io_aware = false;
-       } else if (discard_type == DPOLICY_FSTRIM) {
-               dpolicy->io_aware = false;
-       } else if (discard_type == DPOLICY_UMOUNT) {
-               dpolicy->max_requests = UINT_MAX;
-               dpolicy->io_aware = false;
-       }
-}
-
-static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
-{
-       dev_t dev = sbi->sb->s_bdev->bd_dev;
-       struct discard_cmd_control *dcc;
-       int err = 0, i;
-
-       if (SM_I(sbi)->dcc_info) {
-               dcc = SM_I(sbi)->dcc_info;
-               goto init_thread;
-       }
-
-       dcc = f2fs_kzalloc(sbi, sizeof(struct discard_cmd_control), GFP_KERNEL);
-       if (!dcc)
-               return -ENOMEM;
-
-       dcc->discard_granularity = DEFAULT_DISCARD_GRANULARITY;
-       INIT_LIST_HEAD(&dcc->entry_list);
-       for (i = 0; i < MAX_PLIST_NUM; i++)
-               INIT_LIST_HEAD(&dcc->pend_list[i]);
-       INIT_LIST_HEAD(&dcc->wait_list);
-       INIT_LIST_HEAD(&dcc->fstrim_list);
-       mutex_init(&dcc->cmd_lock);
-       atomic_set(&dcc->issued_discard, 0);
-       atomic_set(&dcc->issing_discard, 0);
-       atomic_set(&dcc->discard_cmd_cnt, 0);
-       dcc->nr_discards = 0;
-       dcc->max_discards = MAIN_SEGS(sbi) << sbi->log_blocks_per_seg;
-       dcc->undiscard_blks = 0;
-       dcc->root = RB_ROOT;
-
-       init_waitqueue_head(&dcc->discard_wait_queue);
-       SM_I(sbi)->dcc_info = dcc;
-init_thread:
-       dcc->f2fs_issue_discard = kthread_run(issue_discard_thread, sbi,
-                               "f2fs_discard-%u:%u", MAJOR(dev), MINOR(dev));
-       if (IS_ERR(dcc->f2fs_issue_discard)) {
-               err = PTR_ERR(dcc->f2fs_issue_discard);
-               kfree(dcc);
-               SM_I(sbi)->dcc_info = NULL;
-               return err;
-       }
-
-       return err;
-}
-
-static void destroy_discard_cmd_control(struct f2fs_sb_info *sbi)
-{
-       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-
-       if (!dcc)
-               return;
-
-       stop_discard_thread(sbi);
-
-       kfree(dcc);
-       SM_I(sbi)->dcc_info = NULL;
-}
-
 static bool __mark_sit_entry_dirty(struct f2fs_sb_info *sbi, unsigned int 
segno)
 {
        struct sit_info *sit_i = SIT_I(sbi);
@@ -2399,60 +1490,6 @@ bool exist_trim_candidates(struct f2fs_sb_info *sbi, 
struct cp_control *cpc)
        return has_candidate;
 }
 
-int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
-{
-       __u64 start = F2FS_BYTES_TO_BLK(range->start);
-       __u64 end = start + F2FS_BYTES_TO_BLK(range->len) - 1;
-       unsigned int start_segno, end_segno;
-       block_t start_block, end_block;
-       struct cp_control cpc;
-       struct discard_policy dpolicy;
-       unsigned long long trimmed = 0;
-       int err = 0;
-
-       if (start >= MAX_BLKADDR(sbi) || range->len < sbi->blocksize)
-               return -EINVAL;
-
-       if (end <= MAIN_BLKADDR(sbi))
-               return -EINVAL;
-
-       if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
-               f2fs_msg(sbi->sb, KERN_WARNING,
-                       "Found FS corruption, run fsck to fix.");
-               return -EIO;
-       }
-
-       /* start/end segment number in main_area */
-       start_segno = (start <= MAIN_BLKADDR(sbi)) ? 0 : GET_SEGNO(sbi, start);
-       end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :
-                                               GET_SEGNO(sbi, end);
-
-       cpc.reason = CP_DISCARD;
-       cpc.trim_minlen = max_t(__u64, 1, F2FS_BYTES_TO_BLK(range->minlen));
-       cpc.trim_start = start_segno;
-       cpc.trim_end = end_segno;
-
-       if (sbi->discard_blks == 0)
-               goto out;
-
-       mutex_lock(&sbi->gc_mutex);
-       err = write_checkpoint(sbi, &cpc);
-       mutex_unlock(&sbi->gc_mutex);
-       if (err)
-               goto out;
-
-       start_block = START_BLOCK(sbi, start_segno);
-       end_block = START_BLOCK(sbi, end_segno + 1);
-
-       init_discard_policy(&dpolicy, DPOLICY_FSTRIM, cpc.trim_minlen);
-       __issue_discard_cmd_range(sbi, &dpolicy, start_block, end_block);
-       trimmed = __wait_discard_cmd_range(sbi, &dpolicy,
-                                       start_block, end_block);
-out:
-       range->len = F2FS_BLK_TO_BYTES(trimmed);
-       return err;
-}
-
 static bool __has_curseg_space(struct f2fs_sb_info *sbi, int type)
 {
        struct curseg_info *curseg = CURSEG_I(sbi, type);
@@ -3993,30 +3030,6 @@ void destroy_segment_manager(struct f2fs_sb_info *sbi)
        kfree(sm_info);
 }
 
-int __init create_discard_caches(void)
-{
-       discard_entry_slab = f2fs_kmem_cache_create("discard_entry",
-                       sizeof(struct discard_entry));
-       if (!discard_entry_slab)
-               goto fail;
-
-       discard_cmd_slab = f2fs_kmem_cache_create("discard_cmd",
-                       sizeof(struct discard_cmd));
-       if (!discard_cmd_slab)
-               goto destroy_discard_entry;
-       return 0;
-destroy_discard_entry:
-       kmem_cache_destroy(discard_entry_slab);
-fail:
-       return -ENOMEM;
-}
-
-void destroy_discard_caches(void)
-{
-       kmem_cache_destroy(discard_cmd_slab);
-       kmem_cache_destroy(discard_entry_slab);
-}
-
 int __init create_segment_manager_caches(void)
 {
        sit_entry_set_slab = f2fs_kmem_cache_create("sit_entry_set",
-- 
2.15.0.55.gc2ece9dc4de6


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