[PATCH 1/3] [RESEND] ipr: Fix locking for unit attention handling

[PATCH 1/3] [RESEND] ipr: Fix locking for unit attention handling

[Brian King]

Make sure we have the host lock held when calling scsi_report_bus_reset. Fixes
a crash seen as the __devices list in the scsi host was changing as we were
iterating through it.

Cc: <stable@vger.kernel.org>
Reviewed-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
---

 drivers/scsi/ipr.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff -puN drivers/scsi/ipr.c~ipr_erp_start_locking drivers/scsi/ipr.c
--- linux/drivers/scsi/ipr.c~ipr_erp_start_locking	2015-07-14 11:10:18.015330839 -0500
+++ linux-bjking1/drivers/scsi/ipr.c	2015-07-14 11:10:50.445165558 -0500
@@ -6263,21 +6263,23 @@ static void ipr_scsi_done(struct ipr_cmn
 	struct ipr_ioa_cfg *ioa_cfg = ipr_cmd->ioa_cfg;
 	struct scsi_cmnd *scsi_cmd = ipr_cmd->scsi_cmd;
 	u32 ioasc = be32_to_cpu(ipr_cmd->s.ioasa.hdr.ioasc);
-	unsigned long hrrq_flags;
+	unsigned long lock_flags;
 
 	scsi_set_resid(scsi_cmd, be32_to_cpu(ipr_cmd->s.ioasa.hdr.residual_data_len));
 
 	if (likely(IPR_IOASC_SENSE_KEY(ioasc) == 0)) {
 		scsi_dma_unmap(scsi_cmd);
 
-		spin_lock_irqsave(ipr_cmd->hrrq->lock, hrrq_flags);
+		spin_lock_irqsave(ipr_cmd->hrrq->lock, lock_flags);
 		list_add_tail(&ipr_cmd->queue, &ipr_cmd->hrrq->hrrq_free_q);
 		scsi_cmd->scsi_done(scsi_cmd);
-		spin_unlock_irqrestore(ipr_cmd->hrrq->lock, hrrq_flags);
+		spin_unlock_irqrestore(ipr_cmd->hrrq->lock, lock_flags);
 	} else {
-		spin_lock_irqsave(ipr_cmd->hrrq->lock, hrrq_flags);
+		spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);
+		spin_lock(&ipr_cmd->hrrq->_lock);
 		ipr_erp_start(ioa_cfg, ipr_cmd);
-		spin_unlock_irqrestore(ipr_cmd->hrrq->lock, hrrq_flags);
+		spin_unlock(&ipr_cmd->hrrq->_lock);
+		spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
 	}
 }
 
_

Re: [PATCH 1/3] [RESEND] ipr: Fix locking for unit attention handling

[Martin K. Petersen]

>>>>> "Brian" == Brian King <brking@linux.vnet.ibm.com> writes:

Brian> Make sure we have the host lock held when calling
Brian> scsi_report_bus_reset. Fixes a crash seen as the __devices list
Brian> in the scsi host was changing as we were iterating through it.

Nit: I take it that renaming lock_flags to hrrq_flags makes sense. But
it muddles what is supposed to be a bugfix patch.

Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH 1/3] [RESEND] ipr: Fix locking for unit attention handling

[Brian King]

On 07/16/2015 08:57 PM, Martin K. Petersen wrote:
>>>>>> "Brian" == Brian King <brking@linux.vnet.ibm.com> writes:
> 
> Brian> Make sure we have the host lock held when calling
> Brian> scsi_report_bus_reset. Fixes a crash seen as the __devices list
> Brian> in the scsi host was changing as we were iterating through it.
> 
> Nit: I take it that renaming lock_flags to hrrq_flags makes sense. But
> it muddles what is supposed to be a bugfix patch.
> 
> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
> 

Correct. Thanks for the review.

-Brian

-- 
Brian King
Power Linux I/O
IBM Linux Technology Center