[PATCH] mptsas: fix dma alignment

[PATCH] mptsas: fix dma alignment

[Vitaly Bordug]

From: Yuri Tikhonov <yur@emcraft.com>

fusion mptsas: fix dma alignment

     Since the 465ff.. commit from James Bottomley relaxes the default
     SCSI DMA alignment from 512 bytes to 4 bytes, then, in the mptsas
     driver, we should explicitly set the alignment to the workable
     512 bytes value.

    Signed-off-by: Ilya Yanok <yanok@emcraft.com>
    Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
    Signed-off-by: Sergei Poselenov <sposelenov@emcraft.com>
    Signed-off-by: Vitaly Bordug <vitb@kernel.crashing.org>
---

 drivers/message/fusion/mptsas.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)


diff --git a/drivers/message/fusion/mptsas.c
b/drivers/message/fusion/mptsas.c index 55ff252..2334f26 100644
--- a/drivers/message/fusion/mptsas.c
+++ b/drivers/message/fusion/mptsas.c
@@ -1843,6 +1843,7 @@ mptsas_slave_alloc(struct scsi_device *sdev)
 	return -ENXIO;
 
  out:
+	blk_queue_update_dma_alignment(sdev->request_queue, 511);
 	vdevice->vtarget->num_luns++;
 	sdev->hostdata = vdevice;
 	return 0;

RE: [PATCH] mptsas: fix dma alignment

[Desai, Kashyap]

Can you send an exact link for "465ff.. commit"?

Thanks,
Kashyap

-----Original Message-----
From: Vitaly Bordug [mailto:vitb@kernel.crashing.org] 
Sent: Wednesday, September 02, 2009 2:34 AM
To: Moore, Eric
Cc: DL-MPT Fusion Linux; linux-scsi@vger.kernel.org
Subject: [PATCH] mptsas: fix dma alignment


From: Yuri Tikhonov <yur@emcraft.com>

fusion mptsas: fix dma alignment

     Since the 465ff.. commit from James Bottomley relaxes the default
     SCSI DMA alignment from 512 bytes to 4 bytes, then, in the mptsas
     driver, we should explicitly set the alignment to the workable
     512 bytes value.

    Signed-off-by: Ilya Yanok <yanok@emcraft.com>
    Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
    Signed-off-by: Sergei Poselenov <sposelenov@emcraft.com>
    Signed-off-by: Vitaly Bordug <vitb@kernel.crashing.org>
---

 drivers/message/fusion/mptsas.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)


diff --git a/drivers/message/fusion/mptsas.c
b/drivers/message/fusion/mptsas.c index 55ff252..2334f26 100644
--- a/drivers/message/fusion/mptsas.c
+++ b/drivers/message/fusion/mptsas.c
@@ -1843,6 +1843,7 @@ mptsas_slave_alloc(struct scsi_device *sdev)
 	return -ENXIO;
 
  out:
+	blk_queue_update_dma_alignment(sdev->request_queue, 511);
 	vdevice->vtarget->num_luns++;
 	sdev->hostdata = vdevice;
 	return 0;

Re: [PATCH] mptsas: fix dma alignment

[Vitaly Bordug]

В Mon, 7 Sep 2009 16:42:54 +0530
"Desai, Kashyap" <Kashyap.Desai@lsi.com> пишет:

> Can you send an exact link for "465ff.. commit"?
> 
Sure, 
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=465ff3185e0cb76d46137335a4d21d0d9d3ac8a2

> Thanks,
> Kashyap
> 
> -----Original Message-----
> From: Vitaly Bordug [mailto:vitb@kernel.crashing.org] 
> Sent: Wednesday, September 02, 2009 2:34 AM
> To: Moore, Eric
> Cc: DL-MPT Fusion Linux; linux-scsi@vger.kernel.org
> Subject: [PATCH] mptsas: fix dma alignment
> 
> 
> From: Yuri Tikhonov <yur@emcraft.com>
> 
> fusion mptsas: fix dma alignment
> 
>      Since the 465ff.. commit from James Bottomley relaxes the default
>      SCSI DMA alignment from 512 bytes to 4 bytes, then, in the mptsas
>      driver, we should explicitly set the alignment to the workable
>      512 bytes value.
> 
>     Signed-off-by: Ilya Yanok <yanok@emcraft.com>
>     Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
>     Signed-off-by: Sergei Poselenov <sposelenov@emcraft.com>
>     Signed-off-by: Vitaly Bordug <vitb@kernel.crashing.org>
> ---
> 
>  drivers/message/fusion/mptsas.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> 
> diff --git a/drivers/message/fusion/mptsas.c
> b/drivers/message/fusion/mptsas.c index 55ff252..2334f26 100644
> --- a/drivers/message/fusion/mptsas.c
> +++ b/drivers/message/fusion/mptsas.c
> @@ -1843,6 +1843,7 @@ mptsas_slave_alloc(struct scsi_device *sdev)
>  	return -ENXIO;
>  
>   out:
> +	blk_queue_update_dma_alignment(sdev->request_queue, 511);
>  	vdevice->vtarget->num_luns++;
>  	sdev->hostdata = vdevice;
>  	return 0;
--
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RE: [PATCH] mptsas: fix dma alignment

[Desai, Kashyap]

After seeing original commit from James, this patch looks OK to me.
Please consider this patch as ACKed by me.

Thanks,
Kashyap

-----Original Message-----
From: Vitaly Bordug [mailto:vitb@kernel.crashing.org] 
Sent: Monday, September 07, 2009 7:16 PM
To: Desai, Kashyap
Cc: Moore, Eric; DL-MPT Fusion Linux; linux-scsi@vger.kernel.org
Subject: Re: [PATCH] mptsas: fix dma alignment

В Mon, 7 Sep 2009 16:42:54 +0530
"Desai, Kashyap" <Kashyap.Desai@lsi.com> пишет:

> Can you send an exact link for "465ff.. commit"?
> 
Sure, 
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=465ff3185e0cb76d46137335a4d21d0d9d3ac8a2

> Thanks,
> Kashyap
> 
> -----Original Message-----
> From: Vitaly Bordug [mailto:vitb@kernel.crashing.org] 
> Sent: Wednesday, September 02, 2009 2:34 AM
> To: Moore, Eric
> Cc: DL-MPT Fusion Linux; linux-scsi@vger.kernel.org
> Subject: [PATCH] mptsas: fix dma alignment
> 
> 
> From: Yuri Tikhonov <yur@emcraft.com>
> 
> fusion mptsas: fix dma alignment
> 
>      Since the 465ff.. commit from James Bottomley relaxes the default
>      SCSI DMA alignment from 512 bytes to 4 bytes, then, in the mptsas
>      driver, we should explicitly set the alignment to the workable
>      512 bytes value.
> 
>     Signed-off-by: Ilya Yanok <yanok@emcraft.com>
>     Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
>     Signed-off-by: Sergei Poselenov <sposelenov@emcraft.com>
>     Signed-off-by: Vitaly Bordug <vitb@kernel.crashing.org>
> ---
> 
>  drivers/message/fusion/mptsas.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> 
> diff --git a/drivers/message/fusion/mptsas.c
> b/drivers/message/fusion/mptsas.c index 55ff252..2334f26 100644
> --- a/drivers/message/fusion/mptsas.c
> +++ b/drivers/message/fusion/mptsas.c
> @@ -1843,6 +1843,7 @@ mptsas_slave_alloc(struct scsi_device *sdev)
>  	return -ENXIO;
>  
>   out:
> +	blk_queue_update_dma_alignment(sdev->request_queue, 511);
>  	vdevice->vtarget->num_luns++;
>  	sdev->hostdata = vdevice;
>  	return 0;
--
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RE: [PATCH] mptsas: fix dma alignment

[James Bottomley]

On Tue, 2009-09-08 at 13:49 +0530, Desai, Kashyap wrote:
> After seeing original commit from James, this patch looks OK to me.
> Please consider this patch as ACKed by me.

If you're sure it's a problem.  The reason for the original was that all
DMA engines (including the old LSI 1010) can transfer on word
boundaries.  I didn't realise the 1030 had regressed in terms of DMA
alignment requirements.

James

RE: [PATCH] mptsas: fix dma alignment

[Moore, Eric]

On Tuesday, September 08, 2009 8:23 AM,  James Bottomley wrote:
> On Tue, 2009-09-08 at 13:49 +0530, Desai, Kashyap wrote:
> > After seeing original commit from James, this patch looks OK to me.
> > Please consider this patch as ACKed by me.
> 
> If you're sure it's a problem.  The reason for the original 
> was that all
> DMA engines (including the old LSI 1010) can transfer on word
> boundaries.  I didn't realise the 1030 had regressed in terms of DMA
> alignment requirements.
> 

James, correct.  The scatter gather elements themselfs have to be on 4 byte boundary.    Thus I don't believe this patch is required.

However the alignment restrictions are for Request Message Frames, chains, and sense buffer can't cross 4GB boundary.  The reason is the driver reports the upper 32bit address in the ioc_init request at driver load time.

Eric