Re: [async_tx-next PATCH v2 2/2] fsldma: Fix cookie issues
From: Dan Williams <hidden>
Date: 2010-03-01 05:14:29
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On Thu, Feb 25, 2010 at 12:39 PM, Steven J. Magnani [off-list ref] wrote:
fsl_dma_update_completed_cookie() appears to calculate the last completed cookie incorrectly in the corner case where DMA on cookie 1 is in progres=
s
quoted hunk ↗ jump to hunk
just following a cookie wrap. Signed-off-by: Steven J. Magnani <redacted> --- diff -uprN a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c--- a/drivers/dma/fsldma.c =A0 =A0 =A02010-02-22 11:16:36.000000000 -0600 +++ b/drivers/dma/fsldma.c =A0 =A0 =A02010-02-22 11:08:41.000000000 -0600@@ -819,8 +819,11 @@ static void fsl_dma_update_completed_coo=A0 =A0 =A0 =A0desc =3D to_fsl_desc(chan->ld_running.prev); =A0 =A0 =A0 =A0if (dma_is_idle(chan)) =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0cookie =3D desc->async_tx.cookie; - =A0 =A0 =A0 else + =A0 =A0 =A0 else { =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0cookie =3D desc->async_tx.cookie - 1; + =A0 =A0 =A0 =A0 =A0 =A0 =A0 if (unlikely(cookie < DMA_MIN_COOKIE)) + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 cookie =3D DMA_MAX_COOKIE; + =A0 =A0 =A0 } =A0 =A0 =A0 =A0chan->completed_cookie =3D cookie; diff -uprN a/include/linux/dmaengine.h b/include/linux/dmaengine.h--- a/include/linux/dmaengine.h 2010-02-22 11:18:11.000000000 -0600 +++ b/include/linux/dmaengine.h 2010-02-22 11:18:30.000000000 -0600@@ -31,6 +31,8 @@=A0* if dma_cookie_t is >0 it's a DMA request cookie, <0 it's an error co=
de
=A0*/ =A0typedef s32 dma_cookie_t; +#define DMA_MIN_COOKIE 1 +#define DMA_MAX_COOKIE ((1 << 31) - 1)
This patch introduces a new warning:: drivers/dma/fsldma.c:825: warning: integer overflow in expression I'll fix this up to use INT_MAX instead. -- Dan powerpc-linux-gnu-gcc --version powerpc-linux-gnu-gcc (Sourcery G++ Lite 4.2-50) 4.2.1