[PATCH] btrfs: drop btrfs_device::can_discard to query directly

[Anand Jain]

We can query the bdev directly when needed at btrfs_discard_extent()
so drop btrfs_device::can_discard.

Signed-off-by: Anand Jain <anand.j...@oracle.com>
Suggested-by: Nikolay Borisov <nbori...@suse.com>
---
 fs/btrfs/extent-tree.c | 5 ++++-
 fs/btrfs/volumes.c     | 8 --------
 fs/btrfs/volumes.h     | 1 -
 3 files changed, 4 insertions(+), 10 deletions(-)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 85a545cf4395..830666c95360 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2145,7 +2145,10 @@ int btrfs_discard_extent(struct btrfs_fs_info *fs_info, 
u64 bytenr,
 
                for (i = 0; i < bbio->num_stripes; i++, stripe++) {
                        u64 bytes;
-                       if (!stripe->dev->can_discard)
+                       struct request_queue *req_q;
+
+                       req_q = bdev_get_queue(stripe->dev->bdev);
+                       if (!blk_queue_discard(req_q))
                                continue;
 
                        ret = btrfs_issue_discard(stripe->dev->bdev,
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ff62919d568f..ff52ecf17402 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -630,8 +630,6 @@ static int btrfs_open_one_device(struct btrfs_fs_devices 
*fs_devices,
        }
 
        q = bdev_get_queue(bdev);
-       if (blk_queue_discard(q))
-               device->can_discard = 1;
        if (!blk_queue_nonrot(q))
                fs_devices->rotating = 1;
 
@@ -2387,8 +2385,6 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, 
const char *device_path
        }
 
        q = bdev_get_queue(bdev);
-       if (blk_queue_discard(q))
-               device->can_discard = 1;
        set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
        device->generation = trans->transid;
        device->io_width = fs_info->sectorsize;
@@ -2539,7 +2535,6 @@ int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info 
*fs_info,
                                  struct btrfs_device *srcdev,
                                  struct btrfs_device **device_out)
 {
-       struct request_queue *q;
        struct btrfs_device *device;
        struct block_device *bdev;
        struct list_head *devices;
@@ -2596,9 +2591,6 @@ int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info 
*fs_info,
        }
        rcu_assign_pointer(device->name, name);
 
-       q = bdev_get_queue(bdev);
-       if (blk_queue_discard(q))
-               device->can_discard = 1;
        mutex_lock(&fs_info->fs_devices->device_list_mutex);
        set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
        device->generation = 0;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 2fbff6902c8d..1cc693716b9a 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -74,7 +74,6 @@ struct btrfs_device {
        fmode_t mode;
 
        unsigned long dev_state;
-       int can_discard;
        int is_tgtdev_for_dev_replace;
        blk_status_t last_flush_error;
        int flush_bio_sent;
-- 
2.15.0

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