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From: Hans Verkuil <hverkuil@xs4all.nl>
To: Linux Media Mailing List <linux-media@vger.kernel.org>
Cc: Mariusz Bialonczyk <manio@skyboo.net>
Subject: Re: [PATCH for v3.18] media: use sg = sg_next(sg) instead of sg++
Date: Fri, 21 Nov 2014 11:50:29 +0100	[thread overview]
Message-ID: <546F18F5.6010407@xs4all.nl> (raw)
In-Reply-To: <546F0E5B.80600@xs4all.nl>

On 11/21/2014 11:05 AM, Hans Verkuil wrote:
> Mariusz,
> 
> Thanks for reporting and testing this so quickly!
> 
> On 11/21/2014 10:20 AM, Hans Verkuil wrote:
>> Several drivers (mostly copy-and-paste) still used sg++ instead of
>> sg = sg_next(sg). Fix them since sg++ won't work if contiguous scatter
>> entries where combined into one larger entry.

I did a bit more research and I found out why this hasn't been a problem
before: the vb1 code will not combine scatterlist entries since it fills
in the entries manually instead of relying on the core code as vb2 does.
So this is a result of switching cx23885 to vb2 after all, although the
driver code really should have been using sg_next regardless.

So I will post only the cx23885 fix to 3.18, the fixes for the other
drivers will be for 3.19 which is crucial for cx88 since that is moved
to vb2 in 3.19 as well, so it will result in a similar bug.

Regards,

	Hans

>>
>> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> 
> Reported-by: Mariusz Bialonczyk <manio@skyboo.net>
> Tested-by: Mariusz Bialonczyk <manio@skyboo.net>
> 
> Regards,
> 
> 	Hans
> 
>> Cc: stable@vger.kernel.org      # for v3.7 and up
>> ---
>>  drivers/media/pci/bt8xx/bttv-risc.c      | 12 ++++++------
>>  drivers/media/pci/cx23885/cx23885-core.c |  6 +++---
>>  drivers/media/pci/cx25821/cx25821-core.c | 12 ++++++------
>>  drivers/media/pci/cx88/cx88-core.c       |  6 +++---
>>  drivers/media/pci/ivtv/ivtv-udma.c       |  2 +-
>>  5 files changed, 19 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/media/pci/bt8xx/bttv-risc.c b/drivers/media/pci/bt8xx/bttv-risc.c
>> index 82cc47d..4d3f05a 100644
>> --- a/drivers/media/pci/bt8xx/bttv-risc.c
>> +++ b/drivers/media/pci/bt8xx/bttv-risc.c
>> @@ -84,7 +84,7 @@ bttv_risc_packed(struct bttv *btv, struct btcx_riscmem *risc,
>>  			continue;
>>  		while (offset && offset >= sg_dma_len(sg)) {
>>  			offset -= sg_dma_len(sg);
>> -			sg++;
>> +			sg = sg_next(sg);
>>  		}
>>  		if (bpl <= sg_dma_len(sg)-offset) {
>>  			/* fits into current chunk */
>> @@ -100,13 +100,13 @@ bttv_risc_packed(struct bttv *btv, struct btcx_riscmem *risc,
>>  			*(rp++)=cpu_to_le32(sg_dma_address(sg)+offset);
>>  			todo -= (sg_dma_len(sg)-offset);
>>  			offset = 0;
>> -			sg++;
>> +			sg = sg_next(sg);
>>  			while (todo > sg_dma_len(sg)) {
>>  				*(rp++)=cpu_to_le32(BT848_RISC_WRITE|
>>  						    sg_dma_len(sg));
>>  				*(rp++)=cpu_to_le32(sg_dma_address(sg));
>>  				todo -= sg_dma_len(sg);
>> -				sg++;
>> +				sg = sg_next(sg);
>>  			}
>>  			*(rp++)=cpu_to_le32(BT848_RISC_WRITE|BT848_RISC_EOL|
>>  					    todo);
>> @@ -187,15 +187,15 @@ bttv_risc_planar(struct bttv *btv, struct btcx_riscmem *risc,
>>  			/* go to next sg entry if needed */
>>  			while (yoffset && yoffset >= sg_dma_len(ysg)) {
>>  				yoffset -= sg_dma_len(ysg);
>> -				ysg++;
>> +				ysg = sg_next(ysg);
>>  			}
>>  			while (uoffset && uoffset >= sg_dma_len(usg)) {
>>  				uoffset -= sg_dma_len(usg);
>> -				usg++;
>> +				usg = sg_next(usg);
>>  			}
>>  			while (voffset && voffset >= sg_dma_len(vsg)) {
>>  				voffset -= sg_dma_len(vsg);
>> -				vsg++;
>> +				vsg = sg_next(vsg);
>>  			}
>>  
>>  			/* calculate max number of bytes we can write */
>> diff --git a/drivers/media/pci/cx23885/cx23885-core.c b/drivers/media/pci/cx23885/cx23885-core.c
>> index 331edda..3bd386c 100644
>> --- a/drivers/media/pci/cx23885/cx23885-core.c
>> +++ b/drivers/media/pci/cx23885/cx23885-core.c
>> @@ -1078,7 +1078,7 @@ static __le32 *cx23885_risc_field(__le32 *rp, struct scatterlist *sglist,
>>  	for (line = 0; line < lines; line++) {
>>  		while (offset && offset >= sg_dma_len(sg)) {
>>  			offset -= sg_dma_len(sg);
>> -			sg++;
>> +			sg = sg_next(sg);
>>  		}
>>  
>>  		if (lpi && line > 0 && !(line % lpi))
>> @@ -1101,14 +1101,14 @@ static __le32 *cx23885_risc_field(__le32 *rp, struct scatterlist *sglist,
>>  			*(rp++) = cpu_to_le32(0); /* bits 63-32 */
>>  			todo -= (sg_dma_len(sg)-offset);
>>  			offset = 0;
>> -			sg++;
>> +			sg = sg_next(sg);
>>  			while (todo > sg_dma_len(sg)) {
>>  				*(rp++) = cpu_to_le32(RISC_WRITE|
>>  						    sg_dma_len(sg));
>>  				*(rp++) = cpu_to_le32(sg_dma_address(sg));
>>  				*(rp++) = cpu_to_le32(0); /* bits 63-32 */
>>  				todo -= sg_dma_len(sg);
>> -				sg++;
>> +				sg = sg_next(sg);
>>  			}
>>  			*(rp++) = cpu_to_le32(RISC_WRITE|RISC_EOL|todo);
>>  			*(rp++) = cpu_to_le32(sg_dma_address(sg));
>> diff --git a/drivers/media/pci/cx25821/cx25821-core.c b/drivers/media/pci/cx25821/cx25821-core.c
>> index e81173c..389fffd 100644
>> --- a/drivers/media/pci/cx25821/cx25821-core.c
>> +++ b/drivers/media/pci/cx25821/cx25821-core.c
>> @@ -996,7 +996,7 @@ static __le32 *cx25821_risc_field(__le32 * rp, struct scatterlist *sglist,
>>  	for (line = 0; line < lines; line++) {
>>  		while (offset && offset >= sg_dma_len(sg)) {
>>  			offset -= sg_dma_len(sg);
>> -			sg++;
>> +			sg = sg_next(sg);
>>  		}
>>  		if (bpl <= sg_dma_len(sg) - offset) {
>>  			/* fits into current chunk */
>> @@ -1014,14 +1014,14 @@ static __le32 *cx25821_risc_field(__le32 * rp, struct scatterlist *sglist,
>>  			*(rp++) = cpu_to_le32(0);	/* bits 63-32 */
>>  			todo -= (sg_dma_len(sg) - offset);
>>  			offset = 0;
>> -			sg++;
>> +			sg = sg_next(sg);
>>  			while (todo > sg_dma_len(sg)) {
>>  				*(rp++) = cpu_to_le32(RISC_WRITE |
>>  						sg_dma_len(sg));
>>  				*(rp++) = cpu_to_le32(sg_dma_address(sg));
>>  				*(rp++) = cpu_to_le32(0);	/* bits 63-32 */
>>  				todo -= sg_dma_len(sg);
>> -				sg++;
>> +				sg = sg_next(sg);
>>  			}
>>  			*(rp++) = cpu_to_le32(RISC_WRITE | RISC_EOL | todo);
>>  			*(rp++) = cpu_to_le32(sg_dma_address(sg));
>> @@ -1101,7 +1101,7 @@ static __le32 *cx25821_risc_field_audio(__le32 * rp, struct scatterlist *sglist,
>>  	for (line = 0; line < lines; line++) {
>>  		while (offset && offset >= sg_dma_len(sg)) {
>>  			offset -= sg_dma_len(sg);
>> -			sg++;
>> +			sg = sg_next(sg);
>>  		}
>>  
>>  		if (lpi && line > 0 && !(line % lpi))
>> @@ -1125,14 +1125,14 @@ static __le32 *cx25821_risc_field_audio(__le32 * rp, struct scatterlist *sglist,
>>  			*(rp++) = cpu_to_le32(0);	/* bits 63-32 */
>>  			todo -= (sg_dma_len(sg) - offset);
>>  			offset = 0;
>> -			sg++;
>> +			sg = sg_next(sg);
>>  			while (todo > sg_dma_len(sg)) {
>>  				*(rp++) = cpu_to_le32(RISC_WRITE |
>>  						sg_dma_len(sg));
>>  				*(rp++) = cpu_to_le32(sg_dma_address(sg));
>>  				*(rp++) = cpu_to_le32(0);	/* bits 63-32 */
>>  				todo -= sg_dma_len(sg);
>> -				sg++;
>> +				sg = sg_next(sg);
>>  			}
>>  			*(rp++) = cpu_to_le32(RISC_WRITE | RISC_EOL | todo);
>>  			*(rp++) = cpu_to_le32(sg_dma_address(sg));
>> diff --git a/drivers/media/pci/cx88/cx88-core.c b/drivers/media/pci/cx88/cx88-core.c
>> index 9fa4acb..dee177e 100644
>> --- a/drivers/media/pci/cx88/cx88-core.c
>> +++ b/drivers/media/pci/cx88/cx88-core.c
>> @@ -95,7 +95,7 @@ static __le32* cx88_risc_field(__le32 *rp, struct scatterlist *sglist,
>>  	for (line = 0; line < lines; line++) {
>>  		while (offset && offset >= sg_dma_len(sg)) {
>>  			offset -= sg_dma_len(sg);
>> -			sg++;
>> +			sg = sg_next(sg);
>>  		}
>>  		if (lpi && line>0 && !(line % lpi))
>>  			sol = RISC_SOL | RISC_IRQ1 | RISC_CNT_INC;
>> @@ -114,13 +114,13 @@ static __le32* cx88_risc_field(__le32 *rp, struct scatterlist *sglist,
>>  			*(rp++)=cpu_to_le32(sg_dma_address(sg)+offset);
>>  			todo -= (sg_dma_len(sg)-offset);
>>  			offset = 0;
>> -			sg++;
>> +			sg = sg_next(sg);
>>  			while (todo > sg_dma_len(sg)) {
>>  				*(rp++)=cpu_to_le32(RISC_WRITE|
>>  						    sg_dma_len(sg));
>>  				*(rp++)=cpu_to_le32(sg_dma_address(sg));
>>  				todo -= sg_dma_len(sg);
>> -				sg++;
>> +				sg = sg_next(sg);
>>  			}
>>  			*(rp++)=cpu_to_le32(RISC_WRITE|RISC_EOL|todo);
>>  			*(rp++)=cpu_to_le32(sg_dma_address(sg));
>> diff --git a/drivers/media/pci/ivtv/ivtv-udma.c b/drivers/media/pci/ivtv/ivtv-udma.c
>> index 7338cb2..bee2329 100644
>> --- a/drivers/media/pci/ivtv/ivtv-udma.c
>> +++ b/drivers/media/pci/ivtv/ivtv-udma.c
>> @@ -76,7 +76,7 @@ void ivtv_udma_fill_sg_array (struct ivtv_user_dma *dma, u32 buffer_offset, u32
>>  	int i;
>>  	struct scatterlist *sg;
>>  
>> -	for (i = 0, sg = dma->SGlist; i < dma->SG_length; i++, sg++) {
>> +	for (i = 0, sg = dma->SGlist; i < dma->SG_length; i++, sg = sg_next(sg)) {
>>  		dma->SGarray[i].size = cpu_to_le32(sg_dma_len(sg));
>>  		dma->SGarray[i].src = cpu_to_le32(sg_dma_address(sg));
>>  		dma->SGarray[i].dst = cpu_to_le32(buffer_offset);
>>
> 
> --
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> 


  reply	other threads:[~2014-11-21 10:50 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-21  9:20 [PATCH for v3.18] media: use sg = sg_next(sg) instead of sg++ Hans Verkuil
2014-11-21 10:05 ` Hans Verkuil
2014-11-21 10:50   ` Hans Verkuil [this message]
2014-11-24 18:24 ` Mauro Carvalho Chehab
2014-11-24 18:37   ` Hans Verkuil
2014-11-24 18:51     ` Mauro Carvalho Chehab
2014-11-24 19:16       ` Hans Verkuil

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