| Message ID | 1267126777-21520-1-git-send-email-steve@digidescorp.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Kumar Gala |
| Headers | show |
On Thu, Feb 25, 2010 at 12:39 PM, Steven J. Magnani <steve@digidescorp.com> 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 progress > just following a cookie wrap. > > Signed-off-by: Steven J. Magnani <steve@digidescorp.com> > --- > diff -uprN a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c > --- a/drivers/dma/fsldma.c 2010-02-22 11:16:36.000000000 -0600 > +++ b/drivers/dma/fsldma.c 2010-02-22 11:08:41.000000000 -0600 > @@ -819,8 +819,11 @@ static void fsl_dma_update_completed_coo > desc = to_fsl_desc(chan->ld_running.prev); > if (dma_is_idle(chan)) > cookie = desc->async_tx.cookie; > - else > + else { > cookie = desc->async_tx.cookie - 1; > + if (unlikely(cookie < DMA_MIN_COOKIE)) > + cookie = DMA_MAX_COOKIE; > + } > > chan->completed_cookie = 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 @@ > * if dma_cookie_t is >0 it's a DMA request cookie, <0 it's an error code > */ > typedef 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
diff -uprN a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c --- a/drivers/dma/fsldma.c 2010-02-22 11:16:36.000000000 -0600 +++ b/drivers/dma/fsldma.c 2010-02-22 11:08:41.000000000 -0600 @@ -819,8 +819,11 @@ static void fsl_dma_update_completed_coo desc = to_fsl_desc(chan->ld_running.prev); if (dma_is_idle(chan)) cookie = desc->async_tx.cookie; - else + else { cookie = desc->async_tx.cookie - 1; + if (unlikely(cookie < DMA_MIN_COOKIE)) + cookie = DMA_MAX_COOKIE; + } chan->completed_cookie = 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 @@ * if dma_cookie_t is >0 it's a DMA request cookie, <0 it's an error code */ typedef s32 dma_cookie_t; +#define DMA_MIN_COOKIE 1 +#define DMA_MAX_COOKIE ((1 << 31) - 1) #define dma_submit_error(cookie) ((cookie) < 0 ? 1 : 0)
fsl_dma_update_completed_cookie() appears to calculate the last completed cookie incorrectly in the corner case where DMA on cookie 1 is in progress just following a cookie wrap. Signed-off-by: Steven J. Magnani <steve@digidescorp.com> ---