Commit aa1c09cb65e2 ("null_blk: Fix locking in zoned mode") changed zone
locking to using the potentially sleeping wait_on_bit_io() function. A
zoned null_blk device must thus be marked as blocking to avoid calls to
queue_rq() from invalid contexts triggering might_sleep() warnings.
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Fixes: aa1c09cb65e2 ("null_blk: Fix locking in zoned mode")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
---
Changes from v1:
* Add "|| g_zoned" to condition for setting blocking to correctly handle
creation through modprobe.
drivers/block/null_blk_main.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 4685ea401d5b..6bcf95d611a3 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -1714,7 +1714,7 @@ static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set)
set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
set->driver_data = NULL;
- if ((nullb && nullb->dev->blocking) || g_blocking)
+ if ((nullb && nullb->dev->blocking) || g_blocking || g_zoned)
set->flags |= BLK_MQ_F_BLOCKING;
return blk_mq_alloc_tag_set(set);
@@ -1736,10 +1736,11 @@ static int null_validate_conf(struct nullb_device *dev)
dev->queue_mode = min_t(unsigned int, dev->queue_mode, NULL_Q_MQ);
dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER);
- /* Do memory allocation, so set blocking */
- if (dev->memory_backed)
+ /* Memory allocation and zone handling may sleep, so set blocking */
+ if (dev->memory_backed || dev->zoned)
dev->blocking = true;
- else /* cache is meaningless */
+ /* Cache is meaningless without memory backing */
+ if (!dev->memory_backed)
dev->cache_size = 0;
dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024,
dev->cache_size);
--
2.26.2
