| Message ID | 1496169551-26868-1-git-send-email-keith.busch@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 05/30/2017 12:39 PM, Keith Busch wrote: > The tagset lock needs to be held when iterating the tag_list, so a > lockdep assert was added when updating number of hardware queues. The > drivers calling this API, however, were unaware of the new requirement, > so are failing the assertion. > > This patch takes the lock within the blk-mq function so the drivers do > not have to be modified in order to be safe. Thanks Keith, applied for 4.12 with the typo in the subject line fixed up.
Keith Busch <keith.busch@intel.com> writes: > The tagset lock needs to be held when iterating the tag_list, so a > lockdep assert was added when updating number of hardware queues. The > drivers calling this API, however, were unaware of the new requirement, > so are failing the assertion. > > This patch takes the lock within the blk-mq function so the drivers do > not have to be modified in order to be safe. > > Fixes: 705cda97e ("blk-mq: Make it safe to use RCU to iterate over blk_mq_tag_set.tag_list") > > Reported-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk> > Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com> > Signed-off-by: Keith Busch <keith.busch@intel.com> I know it is already applied but, FWIW, I can confirm it fixed the issue in our CI. Feel free to add: Tested-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk> Thanks again, Keith.
diff --git a/block/blk-mq.c b/block/blk-mq.c index f2224ffd..1bccced 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2641,7 +2641,8 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) return ret; } -void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) +static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, + int nr_hw_queues) { struct request_queue *q; @@ -2665,6 +2666,13 @@ void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) list_for_each_entry(q, &set->tag_list, tag_set_list) blk_mq_unfreeze_queue(q); } + +void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) +{ + mutex_lock(&set->tag_list_lock); + __blk_mq_update_nr_hw_queues(set, nr_hw_queues); + mutex_unlock(&set->tag_list_lock); +} EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues); /* Enable polling stats and return whether they were already enabled. */
The tagset lock needs to be held when iterating the tag_list, so a lockdep assert was added when updating number of hardware queues. The drivers calling this API, however, were unaware of the new requirement, so are failing the assertion. This patch takes the lock within the blk-mq function so the drivers do not have to be modified in order to be safe. Fixes: 705cda97e ("blk-mq: Make it safe to use RCU to iterate over blk_mq_tag_set.tag_list") Reported-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk> Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com> Signed-off-by: Keith Busch <keith.busch@intel.com> --- block/blk-mq.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)