Modify disk_update_zone_resources() to freeze the device queue before
updating the number of zones, zone capacity and other zone related
resources. The locking order resulting from the call to
queue_limits_commit_update_frozen() is preserved, that is, the queue
limits lock is first taken by calling queue_limits_start_update() before
freezing the queue, and the queue is unfrozen after executing
queue_limits_commit_update(), which replaces the call to
queue_limits_commit_update_frozen().
This change ensures that there are no in-flights I/Os when the zone
resources are updated due to a zone revalidation. In case of error when
the limits are applied, directly call disk_free_zone_resources() from
disk_update_zone_resources() while the disk queue is still frozen to
avoid needing to freeze & unfreeze the queue again in
blk_revalidate_disk_zones(), thus simplifying that function code a
little.
Fixes: 0b83c86b444a ("block: Prevent potential deadlock in
blk_revalidate_disk_zones()")
Cc: [email protected]
Signed-off-by: Damien Le Moal <[email protected]>
---
block/blk-zoned.c | 42 ++++++++++++++++++++++++------------------
1 file changed, 24 insertions(+), 18 deletions(-)
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 1621e8f78338..39381f2b2e94 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -1557,8 +1557,13 @@ static int disk_update_zone_resources(struct gendisk
*disk,
{
struct request_queue *q = disk->queue;
unsigned int nr_seq_zones, nr_conv_zones;
- unsigned int pool_size;
+ unsigned int pool_size, memflags;
struct queue_limits lim;
+ int ret = 0;
+
+ lim = queue_limits_start_update(q);
+
+ memflags = blk_mq_freeze_queue(q);
disk->nr_zones = args->nr_zones;
disk->zone_capacity = args->zone_capacity;
@@ -1568,11 +1573,10 @@ static int disk_update_zone_resources(struct gendisk
*disk,
if (nr_conv_zones >= disk->nr_zones) {
pr_warn("%s: Invalid number of conventional zones %u / %u\n",
disk->disk_name, nr_conv_zones, disk->nr_zones);
- return -ENODEV;
+ ret = -ENODEV;
+ goto unfreeze;
}
- lim = queue_limits_start_update(q);
-
/*
* Some devices can advertize zone resource limits that are larger than
* the number of sequential zones of the zoned block device, e.g. a
@@ -1609,7 +1613,15 @@ static int disk_update_zone_resources(struct gendisk
*disk,
}
commit:
- return queue_limits_commit_update_frozen(q, &lim);
+ ret = queue_limits_commit_update(q, &lim);
+
+unfreeze:
+ if (ret)
+ disk_free_zone_resources(disk);
+
+ blk_mq_unfreeze_queue(q, memflags);
+
+ return ret;
}
static int blk_revalidate_conv_zone(struct blk_zone *zone, unsigned int idx,
@@ -1774,7 +1786,7 @@ int blk_revalidate_disk_zones(struct gendisk *disk)
sector_t zone_sectors = q->limits.chunk_sectors;
sector_t capacity = get_capacity(disk);
struct blk_revalidate_zone_args args = { };
- unsigned int noio_flag;
+ unsigned int memflags, noio_flag;
int ret = -ENOMEM;
if (WARN_ON_ONCE(!blk_queue_is_zoned(q)))
@@ -1824,20 +1836,14 @@ int blk_revalidate_disk_zones(struct gendisk *disk)
ret = -ENODEV;
}
- /*
- * Set the new disk zone parameters only once the queue is frozen and
- * all I/Os are completed.
- */
if (ret > 0)
- ret = disk_update_zone_resources(disk, &args);
- else
- pr_warn("%s: failed to revalidate zones\n", disk->disk_name);
- if (ret) {
- unsigned int memflags = blk_mq_freeze_queue(q);
+ return disk_update_zone_resources(disk, &args);
- disk_free_zone_resources(disk);
- blk_mq_unfreeze_queue(q, memflags);
- }
+ pr_warn("%s: failed to revalidate zones\n", disk->disk_name);
+
+ memflags = blk_mq_freeze_queue(q);
+ disk_free_zone_resources(disk);
+ blk_mq_unfreeze_queue(q, memflags);
return ret;
}
--
2.51.0
