Re: [PATCH] scsi: qla2xxx: deadlock by configfs_depend_item

From: Martin K. Petersen
Date: Wed Dec 19 2018 - 21:27:42 EST



Anatoliy,

> The intent of invoking configfs_depend_item in commit 7474f52a82d51
> ("tcm_qla2xxx: Perform configfs depend/undepend for base_tpg") was to
> prevent a physical Fibre Channel port removal when virtual (NPIV)
> ports announced through that physical port are active. The change
> does not work as expected: it makes enabled physical port dependent on
> target configfs subsystem (the port's parent), something the configfs
> guarantees anyway.
>
> Besides, scheduling work in a worker thread and waiting for the work's
> completion is not really a valid workaround for the requirement not to
> call configfs_depend_item from a configfs callback: the call
> occasionally deadlocks.
>
> Thus, removing configfs_depend_item calls does not break anything and
> fixes the deadlock problem.

Applied to 4.21/scsi-queue, thank you!

--
Martin K. Petersen Oracle Linux Engineering