* [PATCH] wd719x: add check for dma mapping errors
@ 2017-01-27 22:30 Alexey Khoroshilov
2017-01-27 22:53 ` James Bottomley
0 siblings, 1 reply; 2+ messages in thread
From: Alexey Khoroshilov @ 2017-01-27 22:30 UTC (permalink / raw)
To: Ondrej Zary, James E.J. Bottomley, Martin K. Petersen
Cc: Alexey Khoroshilov, linux-scsi, linux-kernel, ldv-project
wd719x_queuecommand() doesn't check if mapping dma memory succeed.
The patch adds the check and failure handling.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
---
drivers/scsi/wd719x.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/scsi/wd719x.c b/drivers/scsi/wd719x.c
index 2a9da2e0ea6b..41ddbdcf02e0 100644
--- a/drivers/scsi/wd719x.c
+++ b/drivers/scsi/wd719x.c
@@ -244,6 +244,12 @@ static int wd719x_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *cmd)
scb->sense_buf_length = SCSI_SENSE_BUFFERSIZE;
cmd->SCp.dma_handle = dma_map_single(&wd->pdev->dev, cmd->sense_buffer,
SCSI_SENSE_BUFFERSIZE, DMA_FROM_DEVICE);
+ if (dma_mapping_error(&wd->pdev->dev, cmd->SCp.dma_handle)) {
+ dev_err(&wd->pdev->dev, "unable to map dma\n");
+ wd719x_finish_cmd(cmd, DID_ERROR);
+ spin_unlock_irqrestore(wd->sh->host_lock, flags);
+ return 0;
+ }
scb->sense_buf = cpu_to_le32(cmd->SCp.dma_handle);
/* request autosense */
--
2.7.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] wd719x: add check for dma mapping errors
2017-01-27 22:30 [PATCH] wd719x: add check for dma mapping errors Alexey Khoroshilov
@ 2017-01-27 22:53 ` James Bottomley
0 siblings, 0 replies; 2+ messages in thread
From: James Bottomley @ 2017-01-27 22:53 UTC (permalink / raw)
To: Alexey Khoroshilov, Ondrej Zary, Martin K. Petersen
Cc: linux-scsi, linux-kernel, ldv-project
On Sat, 2017-01-28 at 01:30 +0300, Alexey Khoroshilov wrote:
> wd719x_queuecommand() doesn't check if mapping dma memory succeed.
> The patch adds the check and failure handling.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
> ---
> drivers/scsi/wd719x.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/scsi/wd719x.c b/drivers/scsi/wd719x.c
> index 2a9da2e0ea6b..41ddbdcf02e0 100644
> --- a/drivers/scsi/wd719x.c
> +++ b/drivers/scsi/wd719x.c
> @@ -244,6 +244,12 @@ static int wd719x_queuecommand(struct Scsi_Host
> *sh, struct scsi_cmnd *cmd)
> scb->sense_buf_length = SCSI_SENSE_BUFFERSIZE;
> cmd->SCp.dma_handle = dma_map_single(&wd->pdev->dev, cmd
> ->sense_buffer,
> SCSI_SENSE_BUFFERSIZE, DMA_FROM_DEVICE);
> + if (dma_mapping_error(&wd->pdev->dev, cmd->SCp.dma_handle))
> {
> + dev_err(&wd->pdev->dev, "unable to map dma\n");
> + wd719x_finish_cmd(cmd, DID_ERROR);
> + spin_unlock_irqrestore(wd->sh->host_lock, flags);
> + return 0;
> + }
I'm not at all convinced of the wisdom of doing this for an ancient
driver: this thing is presumably x86 and ancient in which case it will
never fail anyway.
However, for the future, a mapping error is transient, meaning we want
the command retried, not errored, so from queuecommand you return
SCSI_MLQUEUE_HOST_BUSY to induce a pause and retry.
James
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