From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Smart Subject: Re: [patch 1/1] FC transport: Locking fix for common-code FC pass-through patch Date: Fri, 26 Jun 2009 11:19:27 -0400 Message-ID: <4A44E6FF.40304@emulex.com> References: <20090626143042.117419000@de.ibm.com> <20090626143517.548984000@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from emulex.emulex.com ([138.239.112.1]:53854 "EHLO emulex.emulex.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1749667AbZFZPT3 (ORCPT ); Fri, 26 Jun 2009 11:19:29 -0400 In-Reply-To: <20090626143517.548984000@de.ibm.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Christof Schmitt Cc: James Bottomley , "linux-scsi@vger.kernel.org" , "linux-s390@vger.kernel.org" , "schwidefsky@de.ibm.com" , "heiko.carstens@de.ibm.com" I had tried to remind James that he needed this patch when he pulled in the pass-thru code. Acked-by: James Smart -- james s Christof Schmitt wrote: > From: Christof Schmitt > > Fix this: > ------------[ cut here ]------------ > Badness at block/blk-core.c:244 > CPU: 0 Tainted: G W 2.6.31-rc1-00004-gd3a263a #3 > Process zfcp_wq (pid: 901, task: 000000002fb7a038, ksp: 000000002f02bc78) > Krnl PSW : 0704300180000000 00000000002141ba (blk_remove_plug+0xb2/0xb8) > R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:3 PM:0 EA:3 > Krnl GPRS: 0000000000000001 0000000000000001 0000000022811440 0000000022811798 > 000000000027ff4e 0000000000000000 0000000000000000 000000002f00f000 > 070000000006a0f4 000000002af70000 000000002af2a800 00000000228d1c00 > 0000000022811440 000000000050c708 000000002f02bca8 000000002f02bc80 > Krnl Code: 00000000002141b0: b9140022 lgfr %r2,%r2 > 00000000002141b4: 07fe bcr 15,%r14 > 00000000002141b6: a7f40001 brc 15,2141b8 > >00000000002141ba: a7f4ffbe brc 15,214136 > 00000000002141be: 0707 bcr 0,%r7 > 00000000002141c0: ebaff0680024 stmg %r10,%r15,104(%r15) > 00000000002141c6: c0d00017c2a9 larl %r13,50c718 > 00000000002141cc: a7f13fc0 tmll %r15,16320 > Call Trace: > ([<000000000050e7d8>] C.272.16122+0x88/0x110) > [<00000000002141ec>] __blk_run_queue+0x2c/0x154 > [<000000000028013a>] fc_remote_port_add+0x85e/0x95c > [<000000000037596e>] zfcp_scsi_rport_work+0xe6/0x148 > [<000000000006908c>] worker_thread+0x25c/0x318 > [<000000000006f10c>] kthread+0x94/0x9c > [<000000000001c2b2>] kernel_thread_starter+0x6/0xc > [<000000000001c2ac>] kernel_thread_starter+0x0/0xc > INFO: lockdep is turned off. > Last Breaking-Event-Address: > [<00000000002141b6>] blk_remove_plug+0xae/0xb8 > > The FC pass-through support triggers the WARN_ON(!irqs_disabled()) in > blk_plug_device. Since blk_plug_device requires being called with > disabled interrupts, use spin_lock_irqsave in fc_bsg_goose_queue to > disable the interrupts before calling into the block layer. > > Signed-off-by: Christof Schmitt > --- > > drivers/scsi/scsi_transport_fc.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff -urpN linux-2.6/drivers/scsi/scsi_transport_fc.c linux-2.6-patched/drivers/scsi/scsi_transport_fc.c > --- linux-2.6/drivers/scsi/scsi_transport_fc.c 2009-06-26 09:56:55.000000000 +0200 > +++ linux-2.6-patched/drivers/scsi/scsi_transport_fc.c 2009-06-26 09:57:06.000000000 +0200 > @@ -3670,13 +3670,14 @@ static void > fc_bsg_goose_queue(struct fc_rport *rport) > { > int flagset; > + unsigned long flags; > > if (!rport->rqst_q) > return; > > get_device(&rport->dev); > > - spin_lock(rport->rqst_q->queue_lock); > + spin_lock_irqsave(rport->rqst_q->queue_lock, flags); > flagset = test_bit(QUEUE_FLAG_REENTER, &rport->rqst_q->queue_flags) && > !test_bit(QUEUE_FLAG_REENTER, &rport->rqst_q->queue_flags); > if (flagset) > @@ -3684,7 +3685,7 @@ fc_bsg_goose_queue(struct fc_rport *rpor > __blk_run_queue(rport->rqst_q); > if (flagset) > queue_flag_clear(QUEUE_FLAG_REENTER, rport->rqst_q); > - spin_unlock(rport->rqst_q->queue_lock); > + spin_unlock_irqrestore(rport->rqst_q->queue_lock, flags); > > put_device(&rport->dev); > } > > >