bttv/cx25821/cx88/ivtv: use sg_next instead of sg++

PATCH New Hans Verkuil 1 participant 1 message Nov 21, 2014

Subsystems (4)

Media (V4L/DVB) Ivtv VIDEO4LINUX driver CX88 VIDEO4LINUX driver Bttv VIDEO4LINUX driver

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Hans Verkuil

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2014-11-21 10:57 UTC #0 lore raw

PATCH 1/1 bttv/cx25821/cx88/ivtv: use sg_next instead of sg++

Never use sg++, always use sg = sg_next(sg). Scatterlist entries can be combined if the memory is contiguous but sg++ won't know about that.

As far as I can tell cx88 and ivtv are really broken because of this, and bttv and cx25821 are OK because vb1 doesn't combine scatterlist entries.

But regardless, sg++ should never be used, only sg_next is safe.

Signed-off-by Hans Verkuil <[email protected]>

---
 drivers/media/pci/bt8xx/bttv-risc.c      | 12 ++++++------
 drivers/media/pci/cx25821/cx25821-core.c | 12 ++++++------
 drivers/media/pci/cx88/cx88-core.c       |  6 +++---
 drivers/media/pci/ivtv/ivtv-udma.c       |  2 +-
 4 files changed, 16 insertions(+), 16 deletions(-)

drivers/media/pci/bt8xx/bttv-risc.c +6 -6

index 82cc47d..4d3f05a 100644
@@ -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 */

drivers/media/pci/cx25821/cx25821-core.c +6 -6

index e81173c..389fffd 100644
@@ -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));

drivers/media/pci/cx88/cx88-core.c +3 -3

index 9fa4acb..dee177e 100644
@@ -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));

drivers/media/pci/ivtv/ivtv-udma.c +1 -1

index 7338cb2..bee2329 100644
@@ -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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