Re: [PATCH 2/2] qla2xxx: Fix missed DMA unmap for aborted cmds

From: Chesnokov Gleb <Chesnokov.G@raidix.com>
To: Himanshu Madhani <himanshu.madhani@oracle.com>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>
Subject: Re: [PATCH 2/2] qla2xxx: Fix missed DMA unmap for aborted cmds
Date: Wed, 20 Apr 2022 14:42:16 +0000	[thread overview]
Message-ID: <AS8PR10MB4952FA41BCC382A6464D842A9DF59@AS8PR10MB4952.EURPRD10.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <4FA3632A-690C-470F-8DEF-663F9AC0CFC8@oracle.com>

> Do you have a log showing this error sequence?

Yes, I have, but the problem is that I have a different target stack, not LIO. So the Call Trace basically contains code sequence from this target stack only,
except for the call of the qlt_free_cmd() that trigger BUG: BUG_ON(cmd->sg_mapped).
Regardless, I think the problem lies on the qlogic driver side, because it is responsible for management to map/unmap sgl list.

> Can you share more details?

What I am observing:

1) Command processing calls qlt_rdy_to_xfer(), maps sgl and sends a command to the firmware
2) Qlogic adapter reset occurs

qla2xxx [0000:82:00.1]-5003:13: ISP System Error - mbx1=110eh mbx2=10h mbx3=dh mbx4=0h mbx5=8a1h mbx6=0h mbx7=0h.
qla2xxx [0000:82:00.1]-d01e:13: -> fwdump no buffer
qla2xxx [0000:82:00.1]-00af:13: Performing ISP error recovery - ha=ffff9dd7d6058000.

3) Somehow the command is being aborted, so that means the command's abort flag has already been set.
I think it may happens something like this:
qla2x00_abort_isp_cleanup() --> qla2x00_abort_all_cmds()

4) The target stack calls qlt_abort_cmd(), and since aborted flag has already been set, this call ended as multiple abort.

5) The target stack calls xmit_response, and since command has already been aborted, this call starts the code sequence to release the command that ended with qlt_free_cmd()

I think I could try to reproduce the problem with LIO target stack, but I have special case with my target stack that lead to reset of qlogic adapter (ISP error recovery) and this is one important part of the error sequence. So, I think I will not be able to reproduce the problem with the LIO until I find out how to similarly reset qlogic adapter during processing active commands that have already been sent to the firmware.