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[122.58.181.142]) by smtp.gmail.com with ESMTPSA id 5sm2580142pfx.63.2020.11.19.23.33.45 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Nov 2020 23:33:48 -0800 (PST) Subject: Re: [PATCH] scsi/atari_scsi: Fix race condition between .queuecommand and EH To: Finn Thain , "James E.J. Bottomley" , "Martin K. Petersen" References: Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org From: Michael Schmitz Message-ID: Date: Fri, 20 Nov 2020 20:33:43 +1300 User-Agent: Mozilla/5.0 (X11; Linux ppc; rv:45.0) Gecko/20100101 Icedove/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Finn, thanks for your patch! Tested on Atari Falcon (with falconide, and pata_falcon modules). Reviewed-by: Michael Schmitz Tested-by: Michael Schmitz Am 20.11.2020 um 17:39 schrieb Finn Thain: > It is possible that bus_reset_cleanup() or .eh_abort_handler could > be invoked during NCR5380_queuecommand(). If that takes place before > the new command is enqueued and after the ST-DMA "lock" has been > acquired, the ST-DMA "lock" will be released again. This will result > in a lost DMA interrupt and a command timeout. Fix this by excluding > EH and interrupt handlers while the new command is enqueued. > > Signed-off-by: Finn Thain > --- > Michael, would you please send your Acked-by or Reviewed-and-tested-by? > These two patches taken together should be equivalent to the one you tested > recently. I've split it into two as that seemed to make more sense. > --- > drivers/scsi/NCR5380.c | 9 ++++++--- > drivers/scsi/atari_scsi.c | 10 +++------- > 2 files changed, 9 insertions(+), 10 deletions(-) > > diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c > index d654a6cc4162..ea4b5749e7da 100644 > --- a/drivers/scsi/NCR5380.c > +++ b/drivers/scsi/NCR5380.c > @@ -580,11 +580,14 @@ static int NCR5380_queue_command(struct Scsi_Host *instance, > > cmd->result = 0; > > - if (!NCR5380_acquire_dma_irq(instance)) > - return SCSI_MLQUEUE_HOST_BUSY; > - > spin_lock_irqsave(&hostdata->lock, flags); > > + if (!NCR5380_acquire_dma_irq(instance)) { > + spin_unlock_irqrestore(&hostdata->lock, flags); > + > + return SCSI_MLQUEUE_HOST_BUSY; > + } > + > /* > * Insert the cmd into the issue queue. Note that REQUEST SENSE > * commands are added to the head of the queue since any command will > diff --git a/drivers/scsi/atari_scsi.c b/drivers/scsi/atari_scsi.c > index a82b63a66635..95d7a3586083 100644 > --- a/drivers/scsi/atari_scsi.c > +++ b/drivers/scsi/atari_scsi.c > @@ -376,15 +376,11 @@ static int falcon_get_lock(struct Scsi_Host *instance) > if (IS_A_TT()) > return 1; > > - if (stdma_is_locked_by(scsi_falcon_intr) && > - instance->hostt->can_queue > 1) > + if (stdma_is_locked_by(scsi_falcon_intr)) > return 1; > > - if (in_interrupt()) > - return stdma_try_lock(scsi_falcon_intr, instance); > - > - stdma_lock(scsi_falcon_intr, instance); > - return 1; > + /* stdma_lock() may sleep which means it can't be used here */ > + return stdma_try_lock(scsi_falcon_intr, instance); > } > > #ifndef MODULE >