From: Bart Van Assche <bvanassche@acm.org>
To: Damien Le Moal <Damien.LeMoal@wdc.com>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"usb-storage@lists.one-eyed-alien.net"
<usb-storage@lists.one-eyed-alien.net>,
Alan Stern <stern@rowland.harvard.edu>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Justin Piszcz <jpiszcz@lucidpixels.com>
Subject: Re: [PATCH] scsi: Fix scsi_get/set_resid() interface
Date: Tue, 29 Oct 2019 08:14:57 -0700 [thread overview]
Message-ID: <7b3cad63-3c0d-0bff-b400-acf85344bfee@acm.org> (raw)
In-Reply-To: <BYAPR04MB5816FF25422E60C168F78308E7610@BYAPR04MB5816.namprd04.prod.outlook.com>
On 10/29/19 1:17 AM, Damien Le Moal wrote:
> So I think changing the interface to unsigned int makes sense in that
> context. Also, unless I am reading this wrong, the above definition you
> quote always lead to resid >= 0, so I do not see what problem you are
> worried about. Could you elaborate your concerns please ?
Hi Damien,
SCSI LLDs handle residual overflow in at least two different ways. I
think the iSCSI initiator handles this by reporting the DID_BAD_TARGET
error code. In the tcm_loop driver I found the following, which I think
is incorrect:
set_host_byte(sc, DID_OK);
if ((se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT) ||
(se_cmd->se_cmd_flags & SCF_UNDERFLOW_BIT))
scsi_set_resid(sc, se_cmd->residual_count);
Seeing this made me wonder what the best approach is for a SCSI LLD to
report a residual overflow?
Thanks,
Bart.
next prev parent reply other threads:[~2019-10-29 15:15 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-28 10:57 [PATCH] scsi: Fix scsi_get/set_resid() interface Damien Le Moal
2019-10-28 20:38 ` Bart Van Assche
2019-10-29 8:17 ` Damien Le Moal
2019-10-29 15:14 ` Bart Van Assche [this message]
2019-10-29 17:59 ` Douglas Gilbert
2019-10-30 1:00 ` Bart Van Assche
2019-10-30 8:30 ` Hannes Reinecke
2019-10-30 15:12 ` Bart Van Assche
2019-10-30 15:18 ` Hannes Reinecke
2019-10-30 15:24 ` Bart Van Assche
2019-10-30 16:18 ` Douglas Gilbert
2019-10-31 7:51 ` Hannes Reinecke
2019-10-31 8:28 ` Hannes Reinecke
2019-10-30 1:07 ` kbuild test robot
2019-10-30 22:56 ` kbuild test robot
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