block: add a bdev_discard_granularity helper

Abstract away implementation details from file systems by providing a
block_device based helper to retrieve the discard granularity.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> [drbd]
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Link: https://lore.kernel.org/r/20220415045258.199825-26-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

4 files changed, 8 insertions, 9 deletions

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 0678ceb50579..a6280dcb3767 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1425,7 +1425,6 @@ static void sanitize_disk_conf(struct drbd_device *device, struct disk_conf *dis
 			       struct drbd_backing_dev *nbc)
 {
 	struct block_device *bdev = nbc->backing_bdev;
-	struct request_queue *q = bdev->bd_disk->queue;
 
 	if (disk_conf->al_extents < DRBD_AL_EXTENTS_MIN)
 		disk_conf->al_extents = DRBD_AL_EXTENTS_MIN;
@@ -1442,12 +1441,14 @@ static void sanitize_disk_conf(struct drbd_device *device, struct disk_conf *dis
 	if (disk_conf->rs_discard_granularity) {
 		int orig_value = disk_conf->rs_discard_granularity;
 		sector_t discard_size = bdev_max_discard_sectors(bdev) << 9;
+		unsigned int discard_granularity = bdev_discard_granularity(bdev);
 		int remainder;
 
-		if (q->limits.discard_granularity > disk_conf->rs_discard_granularity)
-			disk_conf->rs_discard_granularity = q->limits.discard_granularity;
+		if (discard_granularity > disk_conf->rs_discard_granularity)
+			disk_conf->rs_discard_granularity = discard_granularity;
 
-		remainder = disk_conf->rs_discard_granularity % q->limits.discard_granularity;
+		remainder = disk_conf->rs_discard_granularity %
+				discard_granularity;
 		disk_conf->rs_discard_granularity += remainder;
 
 		if (disk_conf->rs_discard_granularity > discard_size)
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 8a4a47da56fe..275c53c7b629 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -1511,7 +1511,6 @@ void drbd_bump_write_ordering(struct drbd_resource *resource, struct drbd_backin
 int drbd_issue_discard_or_zero_out(struct drbd_device *device, sector_t start, unsigned int nr_sectors, int flags)
 {
 	struct block_device *bdev = device->ldev->backing_bdev;
-	struct request_queue *q = bdev_get_queue(bdev);
 	sector_t tmp, nr;
 	unsigned int max_discard_sectors, granularity;
 	int alignment;
@@ -1521,7 +1520,7 @@ int drbd_issue_discard_or_zero_out(struct drbd_device *device, sector_t start, u
 		goto zero_out;
 
 	/* Zero-sector (unknown) and one-sector granularities are the same.  */
-	granularity = max(q->limits.discard_granularity >> 9, 1U);
+	granularity = max(bdev_discard_granularity(bdev) >> 9, 1U);
 	alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
 
 	max_discard_sectors = min(bdev_max_discard_sectors(bdev), (1U << 22));
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 0e061c9896ef..976cf987b392 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -759,7 +759,7 @@ static void loop_config_discard(struct loop_device *lo)
 		struct request_queue *backingq = bdev_get_queue(I_BDEV(inode));
 
 		max_discard_sectors = backingq->limits.max_write_zeroes_sectors;
-		granularity = backingq->limits.discard_granularity ?:
+		granularity = bdev_discard_granularity(I_BDEV(inode)) ?:
 			queue_physical_block_size(backingq);
 
 	/*
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 6cb9f8784327..25f33eb25337 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -835,7 +835,6 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name)
 bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib,
 				       struct block_device *bdev)
 {
-	struct request_queue *q = bdev_get_queue(bdev);
 	int block_size = bdev_logical_block_size(bdev);
 
 	if (!bdev_max_discard_sectors(bdev))
@@ -847,7 +846,7 @@ bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib,
 	 * Currently hardcoded to 1 in Linux/SCSI code..
 	 */
 	attrib->max_unmap_block_desc_count = 1;
-	attrib->unmap_granularity = q->limits.discard_granularity / block_size;
+	attrib->unmap_granularity = bdev_discard_granularity(bdev) / block_size;
 	attrib->unmap_granularity_alignment =
 		bdev_discard_alignment(bdev) / block_size;
 	return true;