No functional changes in this patch, we just set aside 3 bits
in the bio/request flags, which can be used to hold a WRITE_LIFE_*
life time hint.
Ensure that we don't merge requests that have different life time
hints assigned to them.
Reviewed-by: Martin K. Petersen <martin.peter...@oracle.com>
Reviewed-by: Christoph Hellwig <h...@lst.de>
Signed-off-by: Jens Axboe <ax...@kernel.dk>
---
block/blk-merge.c | 16 ++++++++++++++++
fs/inode.c | 9 +++++++++
include/linux/blk_types.h | 31 +++++++++++++++++++++++++++++++
include/linux/fs.h | 2 ++
4 files changed, 58 insertions(+)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 5df13041b851..be1e955db75e 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -673,6 +673,14 @@ static struct request *attempt_merge(struct request_queue
*q,
return NULL;
/*
+ * Don't allow merge of different write hints, or for a hint with
+ * non-hint IO.
+ */
+ if ((req->cmd_flags & REQ_WRITE_LIFE_MASK) !=
+ (next->cmd_flags & REQ_WRITE_LIFE_MASK))
+ return NULL;
+
+ /*
* If we are allowed to merge, then append bio list
* from next to rq and release next. merge_requests_fn
* will have updated segment counts, update sector
@@ -791,6 +799,14 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
!blk_write_same_mergeable(rq->bio, bio))
return false;
+ /*
+ * Don't allow merge of different write hints, or for a hint with
+ * non-hint IO.
+ */
+ if ((rq->cmd_flags & REQ_WRITE_LIFE_MASK) !=
+ (bio->bi_opf & REQ_WRITE_LIFE_MASK))
+ return false;
+
return true;
}
diff --git a/fs/inode.c b/fs/inode.c
index defb015a2c6d..66cc431c9a96 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2131,3 +2131,12 @@ void inode_set_write_hint(struct inode *inode, enum
rw_hint hint)
inode_unlock(inode);
}
}
+
+/*
+ * Returns block write hint mask for the inode
+ */
+unsigned int inode_hint_to_opf(struct inode *inode)
+{
+ return write_hint_to_opf(inode_write_hint(inode));
+}
+EXPORT_SYMBOL(inode_hint_to_opf);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index e210da6d14b8..0d44dce19d9f 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -7,6 +7,7 @@
#include <linux/types.h>
#include <linux/bvec.h>
+#include <linux/fs.h>
struct bio_set;
struct bio;
@@ -223,6 +224,10 @@ enum req_flag_bits {
__REQ_RAHEAD, /* read ahead, can fail anytime */
__REQ_BACKGROUND, /* background IO */
+ __REQ_WRITE_HINT_SHIFT, /* 3 bits for life time hint */
+ __REQ_WRITE_HINT_PAD1,
+ __REQ_WRITE_HINT_PAD2,
+
/* command specific flags for REQ_OP_WRITE_ZEROES: */
__REQ_NOUNMAP, /* do not free blocks when zeroing */
@@ -244,6 +249,13 @@ enum req_flag_bits {
#define REQ_RAHEAD (1ULL << __REQ_RAHEAD)
#define REQ_BACKGROUND (1ULL << __REQ_BACKGROUND)
+#define REQ_WRITE_SHORT (WRITE_LIFE_SHORT <<
__REQ_WRITE_HINT_SHIFT)
+#define REQ_WRITE_MEDIUM (WRITE_LIFE_MEDIUM << __REQ_WRITE_HINT_SHIFT)
+#define REQ_WRITE_LONG (WRITE_LIFE_LONG << __REQ_WRITE_HINT_SHIFT)
+#define REQ_WRITE_EXTREME (WRITE_LIFE_EXTREME << __REQ_WRITE_HINT_SHIFT)
+
+#define REQ_WRITE_LIFE_MASK (0x7 << __REQ_WRITE_HINT_SHIFT)
+
#define REQ_NOUNMAP (1ULL << __REQ_NOUNMAP)
#define REQ_NOWAIT (1ULL << __REQ_NOWAIT)
@@ -335,4 +347,23 @@ struct blk_rq_stat {
u64 batch;
};
+static inline unsigned int write_hint_to_opf(enum rw_hint hint)
+{
+ return hint << __REQ_WRITE_HINT_SHIFT;
+}
+
+/*
+ * Don't let drivers see WRITE_LIFE_NOT_SET, return NONE for that
+ */
+static inline enum rw_hint opf_to_write_hint(unsigned int opf)
+{
+ enum rw_hint ret;
+
+ ret = (opf & REQ_WRITE_LIFE_MASK) >> __REQ_WRITE_HINT_SHIFT;
+ if (ret == WRITE_LIFE_NOT_SET)
+ ret = WRITE_LIFE_NONE;
+
+ return ret;
+}
+
#endif /* __LINUX_BLK_TYPES_H */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0ef5d110d2bc..86888a6ccad1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1912,6 +1912,8 @@ static inline bool HAS_UNMAPPED_ID(struct inode *inode)
return !uid_valid(inode->i_uid) || !gid_valid(inode->i_gid);
}
+extern unsigned int inode_hint_to_opf(struct inode *inode);
+
static inline unsigned int write_hint_to_mask(enum rw_hint hint,
unsigned int shift)
{
--
2.7.4
