btrfs: use a local variable for fs_devices pointer in btrfs_dev_replace_finishing

In the function btrfs_dev_replace_finishing, we dereferenced
fs_info->fs_devices 6 times. Use keep local variable for that.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index e66a7a9..a7dd6ba 100644 (file)
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -854,6 +854,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
                                       int scrub_ret)
 {
        struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
+       struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
        struct btrfs_device *tgt_device;
        struct btrfs_device *src_device;
        struct btrfs_root *root = fs_info->tree_root;
@@ -903,12 +904,12 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
                WARN_ON(ret);
 
                /* Prevent write_all_supers() during the finishing procedure */
-               mutex_lock(&fs_info->fs_devices->device_list_mutex);
+               mutex_lock(&fs_devices->device_list_mutex);
                /* Prevent new chunks being allocated on the source device */
                mutex_lock(&fs_info->chunk_mutex);
 
                if (!list_empty(&src_device->post_commit_list)) {
-                       mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+                       mutex_unlock(&fs_devices->device_list_mutex);
                        mutex_unlock(&fs_info->chunk_mutex);
                } else {
                        break;
@@ -945,7 +946,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 error:
                up_write(&dev_replace->rwsem);
                mutex_unlock(&fs_info->chunk_mutex);
-               mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+               mutex_unlock(&fs_devices->device_list_mutex);
                btrfs_rm_dev_replace_blocked(fs_info);
                if (tgt_device)
                        btrfs_destroy_dev_replace_tgtdev(tgt_device);
@@ -974,8 +975,8 @@ error:
 
        btrfs_assign_next_active_device(src_device, tgt_device);
 
-       list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list);
-       fs_info->fs_devices->rw_devices++;
+       list_add(&tgt_device->dev_alloc_list, &fs_devices->alloc_list);
+       fs_devices->rw_devices++;
 
        up_write(&dev_replace->rwsem);
        btrfs_rm_dev_replace_blocked(fs_info);
@@ -998,7 +999,7 @@ error:
         * belong to this filesystem.
         */
        mutex_unlock(&fs_info->chunk_mutex);
-       mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+       mutex_unlock(&fs_devices->device_list_mutex);
 
        /* replace the sysfs entry */
        btrfs_sysfs_remove_device(src_device);