[PATCH 07/15] block: use queue_limits_commit_update in queue_discard_max_store

[Christoph Hellwig]

Convert queue_discard_max_store to use queue_limits_commit_update to
check and update the max_discard_sectors limit and freeze the queue
before doing so to ensure we don't have requests in flight while
changing the limits.

Signed-off-by: Christoph Hellwig <h...@lst.de>
Reviewed-by: Keith Busch <kbu...@kernel.org>
Reviewed-by: Chaitanya Kulkarni <k...@nvidia.com>
Reviewed-by: Ming Lei <ming....@redhat.com>
Reviewed-by: Damien Le Moal <dlem...@kernel.org>
Reviewed-by: Martin K. Petersen <martin.peter...@oracle.com>
Reviewed-by: Hannes Reinecke <h...@suse.de>
---
 block/blk-sysfs.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index a1ec27f0ba4150..8c8f69d8ba48ee 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -175,7 +175,9 @@ static ssize_t queue_discard_max_store(struct request_queue 
*q,
                                       const char *page, size_t count)
 {
        unsigned long max_discard_bytes;
+       struct queue_limits lim;
        ssize_t ret;
+       int err;
 
        ret = queue_var_store(&max_discard_bytes, page, count);
        if (ret < 0)
@@ -187,9 +189,14 @@ static ssize_t queue_discard_max_store(struct 
request_queue *q,
        if ((max_discard_bytes >> SECTOR_SHIFT) > UINT_MAX)
                return -EINVAL;
 
-       q->limits.max_user_discard_sectors = max_discard_bytes >> SECTOR_SHIFT;
-       q->limits.max_discard_sectors = min(q->limits.max_hw_discard_sectors,
-                                           q->limits.max_user_discard_sectors);
+       blk_mq_freeze_queue(q);
+       lim = queue_limits_start_update(q);
+       lim.max_user_discard_sectors = max_discard_bytes >> SECTOR_SHIFT;
+       err = queue_limits_commit_update(q, &lim);
+       blk_mq_unfreeze_queue(q);
+
+       if (err)
+               return err;
        return ret;
 }
 
-- 
2.39.2