scsi: sd: Move sd_read_cpr() out of the q->limits_lock region
Commit 804e498e ("sd: convert to the atomic queue limits API") introduced pairs of function calls to queue_limits_start_update() and queue_limits_commit_update(). These two functions lock and unlock q->limits_lock. In sd_revalidate_disk(), sd_read_cpr() is called after queue_limits_start_update() call and before queue_limits_commit_update() call. sd_read_cpr() locks q->sysfs_dir_lock and &q->sysfs_lock. Then new lock dependencies were created between q->limits_lock, q->sysfs_dir_lock and q->sysfs_lock, as follows: sd_revalidate_disk queue_limits_start_update mutex_lock(&q->limits_lock) sd_read_cpr disk_set_independent_access_ranges mutex_lock(&q->sysfs_dir_lock) mutex_lock(&q->sysfs_lock) mutex_unlock(&q->sysfs_lock) mutex_unlock(&q->sysfs_dir_lock) queue_limits_commit_update mutex_unlock(&q->limits_lock) However, the three locks already had reversed dependencies in other places. Then the new dependencies triggered the lockdep WARN "possible circular locking dependency detected" [1]. This WARN was observed by running the blktests test case srp/002. To avoid the WARN, move the sd_read_cpr() call in sd_revalidate_disk() after the queue_limits_commit_update() call. In other words, move the sd_read_cpr() call out of the q->limits_lock region. [1] https://lore.kernel.org/linux-scsi/vlmv53ni3ltwxplig5qnw4xsl2h6ccxijfbqzekx76vxoim5a5@dekv7q3es3tx/ Fixes: 804e498e ("sd: convert to the atomic queue limits API") Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Link: https://lore.kernel.org/r/20240801054234.540532-1-shinichiro.kawasaki@wdc.comTested-by: Luca Coelho <luciano.coelho@intel.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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