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

[Anand Jain <anand.jain@oracle.com>]

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

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Suggested-by: Nikolay Borisov <nborisov@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