From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boaz Harrosh Subject: Re: [PATCH] 2.6.25-rc4-git3 - inquiry cmd issued via /dev/sg? device causes infinite loop in 2.6.24 Date: Tue, 18 Mar 2008 19:19:05 +0200 Message-ID: <47DFF989.80903@panasas.com> References: <47D7035F.5000700@sgi.com> <47D7B4A1.6020909@panasas.com> <47D7FECE.1020901@sgi.com> <47D8002C.9010306@panasas.com> <47DA798E.5080305@sgi.com> <47DFE9E4.6070301@sgi.com> <47DFEBBD.7080702@panasas.com> <47DFF369.90805@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from gw-colo-pa.panasas.com ([66.238.117.130]:8491 "EHLO cassoulet.panasas.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753525AbYCSTxr (ORCPT ); Wed, 19 Mar 2008 15:53:47 -0400 In-Reply-To: <47DFF369.90805@sgi.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Michael Reed Cc: linux-scsi On Tue, Mar 18 2008 at 18:52 +0200, Michael Reed wrote: > > Boaz Harrosh wrote: >> On Tue, Mar 18 2008 at 18:12 +0200, Michael Reed wrote: >>> Michael Reed wrote: >>>> Boaz Harrosh wrote: >>>> >>>>>>> Just to demonstrate what I mean a patch is attached. Just as an RFC, totally >>>>>>> untested. >>>>>> I can try this out and see what happens. >>>>>> >>>>>> >>>>> Will not compile here is a cleaner one >>>> Still in my queue. Hopefully I'll get to poke at this today. >>> Patch compiles cleanly and appears to have no effect on the misc. >>> sg_* commands I've executed including sg_dd, sg_inq, sg_luns, sg_readcap. >>> >>> Mike >>> >>>> Mike >>>> >> >> >> If you remove the original fix to sg.c >> ([PATCH] 2.6.25-rc4-git3 - inquiry cmd issued via /dev/sg? device causes infinite loop in 2.6.24) >> >> and apply this patch, does it solve your original infinite loop? > > Unfortunately, the infinite loop only occurred at 2.6.24. I'll see if > I can break the current rc by removing some known fixes. > > Care to gen a patch for 2.6.24? > > Mike > >> Thanks >> Boaz >> here is the same principle on Linux 2.6.24 --- [PATCH] scsi: Always complete BLOCK_PC commands Current code, in some IO combinations could wrongly retry a BLOCK_PC command in chunks. This was never intended. Fix it that BLOCK_PC will always complete atomically Signed-off-by: Boaz Harrosh --- git-diff --stat -p drivers/scsi/scsi_lib.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index a9ac5b1..ae32012 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -966,7 +966,16 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) req->sense_len = len; } } + good_bytes = req->data_len; req->data_len = cmd->resid; +retry_end_req: + if (scsi_end_request(cmd, 1, good_bytes, 0) != NULL) { + WARN_ON(1); + good_bytes = req->data_len; + goto retry_end_req; + } + + return; } /*