Btrfs: cleanup unused num_can_discard in fs_devices

The member variants - num_can_discard - of fs_devices structure
are set, but no one use them to do anything. so remove them.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>

2 files changed, 2 insertions, 15 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e9676a424309..483fc6d45299 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -720,8 +720,6 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
                         fs_devices->rw_devices--;
                 }
 
-                if (device->can_discard)
-                        fs_devices->num_can_discard--;
                 if (device->missing)
                         fs_devices->missing_devices--;
 
@@ -828,10 +826,8 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
                 }
 
                 q = bdev_get_queue(bdev);
-                if (blk_queue_discard(q)) {
+                if (blk_queue_discard(q))
                         device->can_discard = 1;
-                        fs_devices->num_can_discard++;
-                }
 
                 device->bdev = bdev;
                 device->in_fs_metadata = 0;
@@ -1835,8 +1831,7 @@ void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info,
                 if (!fs_devices->seeding)
                         fs_devices->rw_devices++;
         }
-        if (srcdev->can_discard)
-                fs_devices->num_can_discard--;
+
         if (srcdev->bdev) {
                 fs_devices->open_devices--;
 
@@ -1886,8 +1881,6 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
                 fs_info->fs_devices->open_devices--;
         }
         fs_info->fs_devices->num_devices--;
-        if (tgtdev->can_discard)
-                fs_info->fs_devices->num_can_discard++;
 
         next_device = list_entry(fs_info->fs_devices->devices.next,
                                  struct btrfs_device, dev_list);
@@ -2008,7 +2001,6 @@ static int btrfs_prepare_sprout(struct btrfs_root *root)
         fs_devices->num_devices = 0;
         fs_devices->open_devices = 0;
         fs_devices->missing_devices = 0;
-        fs_devices->num_can_discard = 0;
         fs_devices->rotating = 0;
         fs_devices->seed = seed_devices;
 
@@ -2200,8 +2192,6 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
         root->fs_info->fs_devices->open_devices++;
         root->fs_info->fs_devices->rw_devices++;
         root->fs_info->fs_devices->total_devices++;
-        if (device->can_discard)
-                root->fs_info->fs_devices->num_can_discard++;
         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
 
         spin_lock(&root->fs_info->free_chunk_lock);
@@ -2371,8 +2361,6 @@ int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
         list_add(&device->dev_list, &fs_info->fs_devices->devices);
         fs_info->fs_devices->num_devices++;
         fs_info->fs_devices->open_devices++;
-        if (device->can_discard)
-                fs_info->fs_devices->num_can_discard++;
         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
 
         *device_out = device;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index e894ac696889..37f8bff97df1 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -124,7 +124,6 @@ struct btrfs_fs_devices {
         u64 rw_devices;
         u64 missing_devices;
         u64 total_rw_bytes;
-        u64 num_can_discard;
         u64 total_devices;
         struct block_device *latest_bdev;