From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Reed Subject: Re: [PATCH] 2.6.25-rc4-git3 - inquiry cmd issued via /dev/sg? device causes infinite loop in 2.6.24 Date: Fri, 14 Mar 2008 08:11:42 -0500 Message-ID: <47DA798E.5080305@sgi.com> References: <47D7035F.5000700@sgi.com> <47D7B4A1.6020909@panasas.com> <47D7FECE.1020901@sgi.com> <47D8002C.9010306@panasas.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from relay2.sgi.com ([192.48.171.30]:45684 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754101AbYCNNLo (ORCPT ); Fri, 14 Mar 2008 09:11:44 -0400 In-Reply-To: <47D8002C.9010306@panasas.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Boaz Harrosh Cc: linux-scsi 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. Mike > > --- > From: Boaz Harrosh > Date: Wed, 12 Mar 2008 13:18:49 +0200 > Subject: [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 > --- > drivers/scsi/scsi_lib.c | 24 +++++++++++++----------- > 1 files changed, 13 insertions(+), 11 deletions(-) > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index ba21d97..4b8b57c 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -784,14 +784,20 @@ EXPORT_SYMBOL(scsi_release_buffers); > * in req->data_len and req->next_rq->data_len. The upper-layer driver can > * decide what to do with this information. > */ > -void scsi_end_bidi_request(struct scsi_cmnd *cmd) > +static void scsi_end_blk_request(struct scsi_cmnd *cmd) > { > struct request *req = cmd->request; > unsigned int dlen = req->data_len; > - unsigned int next_dlen = req->next_rq->data_len; > + unsigned int next_dlen; > > - req->data_len = scsi_out(cmd)->resid; > - req->next_rq->data_len = scsi_in(cmd)->resid; > + if (blk_bidi_rq(req)) { > + next_dlen = req->next_rq->data_len; > + req->data_len = scsi_out(cmd)->resid; > + req->next_rq->data_len = scsi_in(cmd)->resid; > + } else { > + next_dlen = 0; > + req->data_len = scsi_get_resid(cmd); > + } > > /* The req and req->next_rq have not been completed */ > BUG_ON(blk_end_bidi_request(req, 0, dlen, next_dlen)); > @@ -866,15 +872,11 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) > req->sense_len = len; > } > } > - if (scsi_bidi_cmnd(cmd)) { > - /* will also release_buffers */ > - scsi_end_bidi_request(cmd); > - return; > - } > - req->data_len = scsi_get_resid(cmd); > + /* will also release_buffers */ > + scsi_end_blk_request(cmd); > + return; > } > > - BUG_ON(blk_bidi_rq(req)); /* bidi not support for !blk_pc_request yet */ > scsi_release_buffers(cmd); > > /*