ACK: [PATCH][SRU][Z] scsi: hpsa: limit transfer length to 1MB

[Stefan Bader]

On 06.10.2017 22:38, Eric Desrochers wrote:
> From: Yadan Fan <ydfan at suse.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1720359
> 
> The hpsa firmware will bypass the cache for any request larger than 1MB,
> so we should cap the request size to avoid any performance degradation
> in kernels later than v4.3
> 
> This degradation is caused from d2be537c3ba3568acd79cd178327b842e60d035e,
> which changed max_sectors_kb to 1280k, but the hardware is able to work
> fine with it, so the true fix should be from hpsa driver.
> 
> Signed-off-by: Yadan Fan <ydfan at suse.com>
> Reviewed-by: Johannes Thumshirn <jthumshirn at suse.de>
> Acked-by: Don Brace <don.brace at microsemi.com>
> Signed-off-by: Martin K. Petersen <martin.petersen at oracle.com>
> (cherry picked from commit e2c7b433f729cedb32514480af8cbdf2fe5cf264)
> Signed-off-by: Eric Desrochers <eric.desrochers at canonical.com>
Acked-by: Stefan Bader <stefan.bader at canonical.com>

> ---
>  drivers/scsi/hpsa.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
> index cbc0c5f..b68ecd1 100644
> --- a/drivers/scsi/hpsa.c
> +++ b/drivers/scsi/hpsa.c
> @@ -948,7 +948,7 @@ static struct scsi_host_template hpsa_driver_template = {
>  #endif
>  	.sdev_attrs = hpsa_sdev_attrs,
>  	.shost_attrs = hpsa_shost_attrs,
> -	.max_sectors = 8192,
> +	.max_sectors = 1024,
>  	.no_write_same = 1,
>  };
>  
> 


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