[PATCH 04/14] block: use queue_limits_commit_update in queue_max_sectors_store

[Christoph Hellwig]

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

Note that this removes the previously held queue_lock that doesn't
protect against any other reader or writer.

Signed-off-by: Christoph Hellwig <h...@lst.de>
Reviewed-by: Damien Le Moal <dlem...@kernel.org>
Reviewed-by: Hannes Reinecke <h...@suse.de>
---
 block/blk-sysfs.c | 37 ++++++++++++-------------------------
 1 file changed, 12 insertions(+), 25 deletions(-)

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 6b2429cad81af1..26607f9825cb05 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -226,35 +226,22 @@ static ssize_t queue_zone_append_max_show(struct 
request_queue *q, char *page)
 static ssize_t
 queue_max_sectors_store(struct request_queue *q, const char *page, size_t 
count)
 {
-       unsigned long var;
-       unsigned int max_sectors_kb,
-               max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
-                       page_kb = 1 << (PAGE_SHIFT - 10);
-       ssize_t ret = queue_var_store(&var, page, count);
+       unsigned long max_sectors_kb;
+       struct queue_limits lim;
+       ssize_t ret;
+       int err;
 
+       ret = queue_var_store(&max_sectors_kb, page, count);
        if (ret < 0)
                return ret;
 
-       max_sectors_kb = (unsigned int)var;
-       max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb,
-                                        q->limits.max_dev_sectors >> 1);
-       if (max_sectors_kb == 0) {
-               q->limits.max_user_sectors = 0;
-               max_sectors_kb = min(max_hw_sectors_kb,
-                                    BLK_DEF_MAX_SECTORS_CAP >> 1);
-       } else {
-               if (max_sectors_kb > max_hw_sectors_kb ||
-                   max_sectors_kb < page_kb)
-                       return -EINVAL;
-               q->limits.max_user_sectors = max_sectors_kb << 1;
-       }
-
-       spin_lock_irq(&q->queue_lock);
-       q->limits.max_sectors = max_sectors_kb << 1;
-       if (q->disk)
-               q->disk->bdi->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
-       spin_unlock_irq(&q->queue_lock);
-
+       blk_mq_freeze_queue(q);
+       lim = queue_limits_start_update(q);
+       lim.max_user_sectors = max_sectors_kb << 1;
+       err = queue_limits_commit_update(q, &lim);
+       blk_mq_unfreeze_queue(q);
+       if (err)
+               return err;
        return ret;
 }
 
-- 
2.39.2