drbd/bsc-1202600_01-remove-QUEUE_FLAG_DISCARD.patch

/*
   This patch is related with following upstream kernel commit.
   This patch uses QUEUE_FLAG_STABLE_WRITES to replace QUEUE_FLAG_DISCARD.
 */

commit 70200574cc229f6ba038259e8142af2aa09e6976
Author: Christoph Hellwig <hch@lst.de>
Date:   Fri Apr 15 06:52:55 2022 +0200

    block: remove QUEUE_FLAG_DISCARD

    Just use a non-zero max_discard_sectors as an indicator for discard
    support, similar to what is done for write zeroes.

    The only places where needs special attention is the RAID5 driver,
    which must clear discard support for security reasons by default,
    even if the default stacking rules would allow for it.

    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: Jan Höppner <hoeppner@linux.ibm.com> [s390]
    Acked-by: Coly Li <colyli@suse.de> [bcache]
    Acked-by: David Sterba <dsterba@suse.com> [btrfs]
    Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
    Link: https://lore.kernel.org/r/20220415045258.199825-25-hch@lst.de
    Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff -Nupr a/drbd/drbd-kernel-compat/tests/have_blk_queue_flag_set.c b/drbd/drbd-kernel-compat/tests/have_blk_queue_flag_set.c
--- a/drbd/drbd-kernel-compat/tests/have_blk_queue_flag_set.c	2022-08-22 18:14:20.639382230 +0800
+++ b/drbd/drbd-kernel-compat/tests/have_blk_queue_flag_set.c	2022-08-22 18:14:43.819285373 +0800
@@ -3,5 +3,5 @@
 
 void dummy(struct request_queue *q)
 {
-	blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
+	blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, q);
 }
diff -Nupr a/drbd/drbd_main.c b/drbd/drbd_main.c
--- a/drbd/drbd_main.c	2022-08-23 08:04:26.097721587 +0800
+++ b/drbd/drbd_main.c	2022-08-23 08:04:41.449655955 +0800
@@ -1574,7 +1574,7 @@ static void assign_p_sizes_qlim(struct d
 		p->qlim->alignment_offset = cpu_to_be32(queue_alignment_offset(q));
 		p->qlim->io_min = cpu_to_be32(queue_io_min(q));
 		p->qlim->io_opt = cpu_to_be32(queue_io_opt(q));
-		p->qlim->discard_enabled = blk_queue_discard(q);
+		p->qlim->discard_enabled = !!bdev_max_discard_sectors(device->ldev->backing_bdev);
 		p->qlim->discard_zeroes_data = queue_discard_zeroes_data(q);
 		p->qlim->write_same_capable = !!q->limits.max_write_same_sectors;
 	} else {
diff -Nupr a/drbd/drbd_nl.c b/drbd/drbd_nl.c
--- a/drbd/drbd_nl.c	2022-08-23 08:04:26.101721570 +0800
+++ b/drbd/drbd_nl.c	2022-08-23 08:04:41.453655938 +0800
@@ -1967,13 +1967,14 @@ static unsigned int drbd_max_discard_sec
 static void decide_on_discard_support(struct drbd_device *device,
 			struct request_queue *q,
 			struct request_queue *b,
-			bool discard_zeroes_if_aligned)
+			bool discard_zeroes_if_aligned,
+			struct drbd_backing_dev *bdev)
 {
 	/* q = drbd device queue (device->rq_queue)
 	 * b = backing device queue (device->ldev->backing_bdev->bd_disk->queue),
 	 *     or NULL if diskless
 	 */
-	bool can_do = b ? blk_queue_discard(b) : true;
+	bool can_do = b ? bdev_max_discard_sectors(bdev->backing_bdev) : true;
 
 	if (can_do && b && !queue_discard_zeroes_data(b) && !discard_zeroes_if_aligned) {
 		can_do = false;
@@ -1992,23 +1993,12 @@ static void decide_on_discard_support(st
 		 * topology on all peers. */
 		blk_queue_discard_granularity(q, 512);
 		q->limits.max_discard_sectors = drbd_max_discard_sectors(device->resource);
-		blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
+		q->limits.max_write_zeroes_sectors =
+			drbd_max_discard_sectors(device->resource);
 	} else {
-		blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q);
 		blk_queue_discard_granularity(q, 0);
 		q->limits.max_discard_sectors = 0;
-	}
-}
-
-static void fixup_discard_if_not_supported(struct request_queue *q)
-{
-	/* To avoid confusion, if this queue does not support discard, clear
-	 * max_discard_sectors, which is what lsblk -D reports to the user.
-	 * Older kernels got this wrong in "stack limits".
-	 * */
-	if (!blk_queue_discard(q)) {
-		blk_queue_max_discard_sectors(q, 0);
-		blk_queue_discard_granularity(q, 0);
+		q->limits.max_write_zeroes_sectors = 0;
 	}
 }
 
@@ -2116,7 +2106,7 @@ static void drbd_setup_queue_param(struc
 	blk_queue_max_hw_sectors(q, max_hw_sectors);
 	/* This is the workaround for "bio would need to, but cannot, be split" */
 	blk_queue_segment_boundary(q, PAGE_SIZE-1);
-	decide_on_discard_support(device, q, b, discard_zeroes_if_aligned);
+	decide_on_discard_support(device, q, b, discard_zeroes_if_aligned, bdev);
 	decide_on_write_same_support(device, q, b, o, disable_write_same);
 
 	if (b) {
@@ -2127,7 +2117,6 @@ static void drbd_setup_queue_param(struc
 		blk_queue_update_readahead(q);
 #endif
 	}
-	fixup_discard_if_not_supported(q);
 	fixup_write_zeroes(device, q);
 }
 
@@ -2233,13 +2222,14 @@ static void sanitize_disk_conf(struct dr
 			       struct drbd_backing_dev *nbc)
 {
 	struct request_queue * const q = nbc->backing_bdev->bd_disk->queue;
+	struct block_device *bdev = nbc->backing_bdev;
 
 	if (disk_conf->al_extents < DRBD_AL_EXTENTS_MIN)
 		disk_conf->al_extents = DRBD_AL_EXTENTS_MIN;
 	if (disk_conf->al_extents > drbd_al_extents_max(nbc))
 		disk_conf->al_extents = drbd_al_extents_max(nbc);
 
-	if (!blk_queue_discard(q) ||
+	if (!bdev_max_discard_sectors(bdev) ||
 	    (!queue_discard_zeroes_data(q) && !disk_conf->discard_zeroes_if_aligned)) {
 		if (disk_conf->rs_discard_granularity) {
 			disk_conf->rs_discard_granularity = 0; /* disable feature */
@@ -2261,7 +2251,7 @@ static void sanitize_disk_conf(struct dr
 		/* compat:
 		 * old kernel has 0 granularity means "unknown" means one sector.
 		 * current kernel has 0 granularity means "discard not supported".
-		 * Not supported is checked above already with !blk_queue_discard(q).
+		 * Not supported is checked above already with !blk_max_discard_sectors().
 		 */
 		unsigned int ql_dg = q->limits.discard_granularity ?: 512;
 
diff -Nupr a/drbd/drbd_receiver.c b/drbd/drbd_receiver.c
--- a/drbd/drbd_receiver.c	2022-08-23 08:04:26.105721553 +0800
+++ b/drbd/drbd_receiver.c	2022-08-23 08:25:31.188262629 +0800
@@ -1686,11 +1686,10 @@ int drbd_issue_discard_or_zero_out(struc
 
 static bool can_do_reliable_discards(struct drbd_device *device)
 {
-	struct request_queue *q = bdev_get_queue(device->ldev->backing_bdev);
 	struct disk_conf *dc;
 	bool can_do;
 
-	if (!blk_queue_discard(q))
+	if (!bdev_max_discard_sectors(device->ldev->backing_bdev))
 		return false;
 
 	if (queue_discard_zeroes_data(q))