From: Hans Verkuil <hverkuil@xs4all.nl>
To: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Linux Media Mailing List <linux-media@vger.kernel.org>
Subject: Re: [PATCH for v3.18] media: use sg = sg_next(sg) instead of sg++
Date: Mon, 24 Nov 2014 20:16:01 +0100 [thread overview]
Message-ID: <547383F1.9080006@xs4all.nl> (raw)
In-Reply-To: <20141124165116.4641ef9e@recife.lan>
On 11/24/2014 07:51 PM, Mauro Carvalho Chehab wrote:
> Em Mon, 24 Nov 2014 19:37:48 +0100
> Hans Verkuil <hverkuil@xs4all.nl> escreveu:
>
>> On 11/24/2014 07:24 PM, Mauro Carvalho Chehab wrote:
>>> Em Fri, 21 Nov 2014 10:20:56 +0100
>>> Hans Verkuil <hverkuil@xs4all.nl> escreveu:
>>>
>>>> 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.
>>>>
>>>> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
>>>> 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)) {
>>>
>>> This hunk seems awkward, at least on my eyes.
>>>
>>> As you've pointed at the description, S/G can be grouped into bigger
>>> segments. So, the maximum number of S/G can actually be less than
>>> dma->SGlist.
>>
>> That's correct, and dma->SG_length is equal to that number. SG_length is assigned
>> with the result of dma_map_sg() which returns "the number of bus address segments
>> mapped (this may be shorter than <nents> passed in if some elements of the
>> scatter/gather list are physically or virtually adjacent and an IOMMU maps them
>> with a single entry)."
>>
>> So the patch is correct.
>
> OK.
>
> Btw, you added this patch at a pull request for Kernel 3.19. Shouldn't it
> be, instead, be sent to 3.18 and c/c stable?
The cx23885 fix is already queued for 3.18. The bttv, cx25821 and cx88 are not
affected since they use vb1 and that won't combine scatterlists. The ivtv patch
could go to 3.18, I guess, but it is in a rarely used part of the driver and it
has been broken for quite some time. I do not feel that it is necessary to fix
for 3.18. IMHO.
Regards,
Hans
prev parent reply other threads:[~2014-11-24 19:16 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
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 [this message]
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