On 2/24/25 14:30, Nilay Shroff wrote:
A queue's elevator can be updated either when modifying nr_hw_queues or through the sysfs scheduler attribute. Currently, elevator switching/ updating is protected using q->sysfs_lock, but this has led to lockdep splats[1] due to inconsistent lock ordering between q->sysfs_lock and the freeze-lock in multiple block layer call sites. As the scope of q->sysfs_lock is not well-defined, its (mis)use has resulted in numerous lockdep warnings. To address this, introduce a new q->elevator_lock, dedicated specifically for protecting elevator switches/updates. And we'd now use this new q->elevator_lock instead of q->sysfs_lock for protecting elevator switches/updates. While at it, make elv_iosched_load_module() a static function, as it is only called from elv_iosched_store(). Also, remove redundant parameters from elv_iosched_load_module() function signature. [1] https://lore.kernel.org/all/67637e70.050a0220.3157ee.000c.GAE@xxxxxxxxxx/ Signed-off-by: Nilay Shroff <nilay@xxxxxxxxxxxxx> --- block/blk-core.c | 1 + block/blk-mq.c | 15 +++++++-------- block/blk-sysfs.c | 32 ++++++++++++++++++++++---------- block/elevator.c | 35 ++++++++++++++++------------------- block/elevator.h | 2 -- block/genhd.c | 9 ++++++--- include/linux/blkdev.h | 5 +++++ 7 files changed, 57 insertions(+), 42 deletions(-)
Reviewed-by: Hannes Reinecke <hare@xxxxxxx> Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@xxxxxxx +49 911 74053 688 SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich
