Commit 2542fc95 authored by Bart Van Assche's avatar Bart Van Assche Committed by Martin K. Petersen
Browse files

scsi: core: Fix the scsi_device_put() might_sleep annotation 

Although most calls of scsi_device_put() happen from non-atomic context,
alua_rtpg_queue() calls this function from atomic context if
alua_rtpg_queue() itself is called from atomic context. alua_rtpg_queue()
is always called from contexts where the caller must hold at least one
reference to the scsi device in question. This means that the reference
taken by alua_rtpg_queue() itself can't be the last one, and thus can be
dropped without entering the code path in which scsi_device_put() might
actually sleep. Hence move the might_sleep() annotation from
scsi_device_put() into scsi_device_dev_release().

[1] https://lore.kernel.org/linux-scsi/b49e37d5-edfb-4c56-3eeb-62c7d5855c00@linux.ibm.com/
[2] https://lore.kernel.org/linux-scsi/55c35e64-a7d4-9072-46fd-e8eae6a90e96@linux.ibm.com/



Note: a significant part of the above description was written by Martin
Wilck.

Fixes: f93ed747 ("scsi: core: Release SCSI devices synchronously")
Cc: Martin Wilck <mwilck@suse.com>
Cc: Steffen Maier <maier@linux.ibm.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sachin Sant <sachinp@linux.ibm.com>
Cc: Benjamin Block <bblock@linux.ibm.com>
Reported-by: default avatarSteffen Maier <maier@linux.ibm.com>
Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Reviewed-by: default avatarMartin Wilck <mwilck@suse.com>
Link: https://lore.kernel.org/r/20230125194311.249553-1-bvanassche@acm.org


Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 0bfe63d0

drivers/scsi/scsi.c

+0 −2
Original line number Diff line number Diff line
@@ -588,8 +588,6 @@ void scsi_device_put(struct scsi_device *sdev) 
{

	struct module *mod = sdev->host->hostt->module;



	might_sleep();



	put_device(&sdev->sdev_gendev);

	module_put(mod);

}

drivers/scsi/scsi_sysfs.c

+2 −0
Original line number Diff line number Diff line
@@ -451,6 +451,8 @@ static void scsi_device_dev_release(struct device *dev) 
	struct scsi_vpd *vpd_pgb0 = NULL, *vpd_pgb1 = NULL, *vpd_pgb2 = NULL;

	unsigned long flags;



	might_sleep();



	scsi_dh_release_device(sdev);



	parent = sdev->sdev_gendev.parent;