Factor out this code into a separate function, so it can be reused by
other code more easily.

Reviewed-by: Christoph Hellwig <h...@lst.de>
Signed-off-by: Martijn Coenen <m...@android.com>
---
 drivers/block/loop.c | 117 +++++++++++++++++++++++++------------------
 1 file changed, 67 insertions(+), 50 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index e281a9f03d96..6a4c0ba225ca 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1251,75 +1251,43 @@ static int loop_clr_fd(struct loop_device *lo)
        return __loop_clr_fd(lo, false);
 }
 
+/**
+ * loop_set_status_from_info - configure device from loop_info
+ * @lo: struct loop_device to configure
+ * @info: struct loop_info64 to configure the device with
+ *
+ * Configures the loop device parameters according to the passed
+ * in loop_info64 configuration.
+ */
 static int
-loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
+loop_set_status_from_info(struct loop_device *lo,
+                         const struct loop_info64 *info)
 {
        int err;
        struct loop_func_table *xfer;
        kuid_t uid = current_uid();
-       struct block_device *bdev;
-       bool partscan = false;
-       bool size_changed = false;
-
-       err = mutex_lock_killable(&loop_ctl_mutex);
-       if (err)
-               return err;
-       if (lo->lo_encrypt_key_size &&
-           !uid_eq(lo->lo_key_owner, uid) &&
-           !capable(CAP_SYS_ADMIN)) {
-               err = -EPERM;
-               goto out_unlock;
-       }
-       if (lo->lo_state != Lo_bound) {
-               err = -ENXIO;
-               goto out_unlock;
-       }
-       if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) {
-               err = -EINVAL;
-               goto out_unlock;
-       }
-
-       if (lo->lo_offset != info->lo_offset ||
-           lo->lo_sizelimit != info->lo_sizelimit) {
-               size_changed = true;
-               sync_blockdev(lo->lo_device);
-               kill_bdev(lo->lo_device);
-       }
 
-       /* I/O need to be drained during transfer transition */
-       blk_mq_freeze_queue(lo->lo_queue);
-
-       if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) {
-               /* If any pages were dirtied after kill_bdev(), try again */
-               err = -EAGAIN;
-               pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
-                       __func__, lo->lo_number, lo->lo_file_name,
-                       lo->lo_device->bd_inode->i_mapping->nrpages);
-               goto out_unfreeze;
-       }
+       if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE)
+               return -EINVAL;
 
        err = loop_release_xfer(lo);
        if (err)
-               goto out_unfreeze;
+               return err;
 
        if (info->lo_encrypt_type) {
                unsigned int type = info->lo_encrypt_type;
 
-               if (type >= MAX_LO_CRYPT) {
-                       err = -EINVAL;
-                       goto out_unfreeze;
-               }
+               if (type >= MAX_LO_CRYPT)
+                       return -EINVAL;
                xfer = xfer_funcs[type];
-               if (xfer == NULL) {
-                       err = -EINVAL;
-                       goto out_unfreeze;
-               }
+               if (xfer == NULL)
+                       return -EINVAL;
        } else
                xfer = NULL;
 
        err = loop_init_xfer(lo, xfer, info);
        if (err)
-               goto out_unfreeze;
+               return err;
 
        lo->lo_offset = info->lo_offset;
        lo->lo_sizelimit = info->lo_sizelimit;
@@ -1346,6 +1314,55 @@ loop_set_status(struct loop_device *lo, const struct 
loop_info64 *info)
                lo->lo_key_owner = uid;
        }
 
+       return 0;
+}
+
+static int
+loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
+{
+       int err;
+       struct block_device *bdev;
+       kuid_t uid = current_uid();
+       bool partscan = false;
+       bool size_changed = false;
+
+       err = mutex_lock_killable(&loop_ctl_mutex);
+       if (err)
+               return err;
+       if (lo->lo_encrypt_key_size &&
+           !uid_eq(lo->lo_key_owner, uid) &&
+           !capable(CAP_SYS_ADMIN)) {
+               err = -EPERM;
+               goto out_unlock;
+       }
+       if (lo->lo_state != Lo_bound) {
+               err = -ENXIO;
+               goto out_unlock;
+       }
+
+       if (lo->lo_offset != info->lo_offset ||
+           lo->lo_sizelimit != info->lo_sizelimit) {
+               size_changed = true;
+               sync_blockdev(lo->lo_device);
+               kill_bdev(lo->lo_device);
+       }
+
+       /* I/O need to be drained during transfer transition */
+       blk_mq_freeze_queue(lo->lo_queue);
+
+       if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) {
+               /* If any pages were dirtied after kill_bdev(), try again */
+               err = -EAGAIN;
+               pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
+                       __func__, lo->lo_number, lo->lo_file_name,
+                       lo->lo_device->bd_inode->i_mapping->nrpages);
+               goto out_unfreeze;
+       }
+
+       err = loop_set_status_from_info(lo, info);
+       if (err)
+               goto out_unfreeze;
+
        if (size_changed) {
                loff_t new_size = get_size(lo->lo_offset, lo->lo_sizelimit,
                                           lo->lo_backing_file);
-- 
2.26.2.645.ge9eca65c58-goog

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