From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH v4] SCSI host lock push-down Date: Sat, 13 Nov 2010 01:01:38 -0500 Message-ID: <4CDE29C2.5040206@garzik.org> References: <1289606118.3015.539.camel@mulgrave.site> <20101113051635.GA11613@havoc.gtf.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20101113051635.GA11613@havoc.gtf.org> Sender: linux-kernel-owner@vger.kernel.org To: Linus Torvalds , James Bottomley Cc: "Nicholas A. Bellinger" , Andrew Morton , linux-scsi , linux-kernel List-Id: linux-scsi@vger.kernel.org On 11/13/2010 12:16 AM, Jeff Garzik wrote: > diff --git a/drivers/scsi/arm/fas216.c b/drivers/scsi/arm/fas216.c > index 9e71ac6..f9581a3 100644 > --- a/drivers/scsi/arm/fas216.c > +++ b/drivers/scsi/arm/fas216.c > @@ -2198,7 +2198,7 @@ no_command: > * Returns: 0 on success, else error. > * Notes: io_request_lock is held, interrupts are disabled. > */ > -int fas216_queue_command(struct scsi_cmnd *SCpnt, > +static int fas216_queue_command_lck(struct scsi_cmnd *SCpnt, > void (*done)(struct scsi_cmnd *)) > { > FAS216_Info *info = (FAS216_Info *)SCpnt->device->host->hostdata; > @@ -2240,6 +2240,8 @@ int fas216_queue_command(struct scsi_cmnd *SCpnt, > return result; > } > > +DEF_SCSI_QCMD(fas216_queue_command) > + > /** > * fas216_internal_done - trigger restart of a waiting thread in fas216_noqueue_command > * @SCpnt: Command to wake > @@ -2263,7 +2265,7 @@ static void fas216_internal_done(struct scsi_cmnd *SCpnt) > * Returns: scsi result code. > * Notes: io_request_lock is held, interrupts are disabled. > */ > -int fas216_noqueue_command(struct scsi_cmnd *SCpnt, > +static int fas216_noqueue_command_lck(struct scsi_cmnd *SCpnt, > void (*done)(struct scsi_cmnd *)) > { > FAS216_Info *info = (FAS216_Info *)SCpnt->device->host->hostdata; > @@ -2277,7 +2279,7 @@ int fas216_noqueue_command(struct scsi_cmnd *SCpnt, > BUG_ON(info->scsi.irq != NO_IRQ); > > info->internal_done = 0; > - fas216_queue_command(SCpnt, fas216_internal_done); > + fas216_queue_command(SCpnt->device->host, SCpnt, fas216_internal_done); > > /* > * This wastes time, since we can't return until the command is hmmmm. Linus's suggestion to add Scsi_Host to queuecommand seems to have had a helpful side effect, exposing a minor bug present in nab's (v1), Andi's (v2), my v3 and v4 push-down patches: A few odd ducks, such as fas16 or ancient megaraid, call their own ->queuecommand directly. None of the major SCSI drivers do this, thankfully. The host lock push-down patch should be calling the _lck function in those rare cases, otherwise we've created a deadlock. Time for v5... Jeff