APPLIED: [precise/trusty/utopic SRU] [1/1] drivers:scsi:storvsc: Fix a bug in handling ring buffer failures that may result in I/O freeze

[Brad Figg]

On Wed, Dec 10, 2014 at 11:09:18AM +0000, Andy Whitcroft wrote:
> From: Long Li <longli at microsoft.com>
> 
> When ring buffer returns an error indicating retry, storvsc may not return a proper error code to SCSI when bounce buffer is not used. This has introduced I/O freeze on RAID running atop storvsc devices. This patch fixes it by always returning a proper error code.
> 
> Signed-off-by: Long Li <longli at microsoft.com>
> Reviewed-by: K. Y. Srinivasan <kys at microsoft.com>
> Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
> Cc: stable at vger.kernel.org
> BugLink: http://bugs.launchpad.net/bugs/1400289
> Signed-off-by: Andy Whitcroft <apw at canonical.com>
> ---
>  drivers/scsi/storvsc_drv.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> index a3b4ce9..d73b740 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -1379,13 +1379,12 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
>  	if (ret == -EAGAIN) {
>  		/* no more space */
>  
> -		if (cmd_request->bounce_sgl_count) {
> +		if (cmd_request->bounce_sgl_count)
>  			destroy_bounce_buffer(cmd_request->bounce_sgl,
>  					cmd_request->bounce_sgl_count);
>  
> -			ret = SCSI_MLQUEUE_DEVICE_BUSY;
> -			goto queue_error;
> -		}
> +		ret = SCSI_MLQUEUE_DEVICE_BUSY;
> +		goto queue_error;
>  	}
>  
>  	return 0;
> -- 
> 1.9.1
> 
> 
> -- 
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Applied to precise, trusty, utopic

-- 
Brad Figg brad.figg at canonical.com http://www.canonical.com