From: Samuel Williams <sam8641@gmail.com>
Date: Sun, 1 Apr 2018 15:00:27 +0000 (-0400)
Subject: media: bttv: Fixed oops error when capturing at yuv410p
X-Git-Tag: android-x86-8.1-r1~932^2~244
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=6f7e780b7e93aed10fe5d32f386add042644cb0b;p=android-x86%2Fkernel.git

media: bttv: Fixed oops error when capturing at yuv410p

When capturing at yuv410p, sg_next was called too many times when chroma is
false, eventually returning NULL. This patch does fix this for my hardware.

Signed-off-by: Samuel Williams <sam8641@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
---

diff --git a/drivers/media/pci/bt8xx/bttv-risc.c b/drivers/media/pci/bt8xx/bttv-risc.c
index 3859dde98be2..6a6be0b49f70 100644
--- a/drivers/media/pci/bt8xx/bttv-risc.c
+++ b/drivers/media/pci/bt8xx/bttv-risc.c
@@ -189,20 +189,21 @@ bttv_risc_planar(struct bttv *btv, struct btcx_riscmem *risc,
 				yoffset -= sg_dma_len(ysg);
 				ysg = sg_next(ysg);
 			}
-			while (uoffset && uoffset >= sg_dma_len(usg)) {
-				uoffset -= sg_dma_len(usg);
-				usg = sg_next(usg);
-			}
-			while (voffset && voffset >= sg_dma_len(vsg)) {
-				voffset -= sg_dma_len(vsg);
-				vsg = sg_next(vsg);
-			}
 
 			/* calculate max number of bytes we can write */
 			ylen = todo;
 			if (yoffset + ylen > sg_dma_len(ysg))
 				ylen = sg_dma_len(ysg) - yoffset;
 			if (chroma) {
+				while (uoffset && uoffset >= sg_dma_len(usg)) {
+					uoffset -= sg_dma_len(usg);
+					usg = sg_next(usg);
+				}
+				while (voffset && voffset >= sg_dma_len(vsg)) {
+					voffset -= sg_dma_len(vsg);
+					vsg = sg_next(vsg);
+				}
+
 				if (uoffset + (ylen>>hshift) > sg_dma_len(usg))
 					ylen = (sg_dma_len(usg) - uoffset) << hshift;
 				if (voffset + (ylen>>hshift) > sg_dma_len(vsg))