| Message ID | 1314050385-9617-3-git-send-email-thomas.abraham@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Aug 23, 2011 at 03:29:44AM +0530, Thomas Abraham wrote: > With the change in dma channels private data information, the pl330 > channel filter function is modified to look for a simple u8 value > instead of the now unused 'struct dma_pl330_peri' value. > > Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org> > --- > arch/arm/plat-samsung/dma-ops.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/plat-samsung/dma-ops.c b/arch/arm/plat-samsung/dma-ops.c > index 6e3d9ab..4f1430b 100644 > --- a/arch/arm/plat-samsung/dma-ops.c > +++ b/arch/arm/plat-samsung/dma-ops.c > @@ -19,8 +19,8 @@ > > static inline bool pl330_filter(struct dma_chan *chan, void *param) > { > - struct dma_pl330_peri *peri = chan->private; > - return peri->peri_id == (unsigned)param; > + u8 *peri_id = chan->private; > + return *peri_id == (unsigned)param; > } As a word of warning - this will fail horribly if you have mixed DMA engines in the system. While we wait for a better scheme, we really need to sort out these filter functions properly and stop poking about in data which may not be what we expect. One solution to that is to move pl330_filter() into drivers/dma/pl330.c and have it check chan->device->dev->driver == &pl330_driver.driver _before_ we start accessing chan->private. That's not a comment against your patch - you're not really changing the brokenness of this function. It would be good to see a follow up patch fixing it properly though.
Hi Russell, On 23 August 2011 03:22, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > On Tue, Aug 23, 2011 at 03:29:44AM +0530, Thomas Abraham wrote: >> With the change in dma channels private data information, the pl330 >> channel filter function is modified to look for a simple u8 value >> instead of the now unused 'struct dma_pl330_peri' value. >> >> Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org> >> --- >> arch/arm/plat-samsung/dma-ops.c | 4 ++-- >> 1 files changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm/plat-samsung/dma-ops.c b/arch/arm/plat-samsung/dma-ops.c >> index 6e3d9ab..4f1430b 100644 >> --- a/arch/arm/plat-samsung/dma-ops.c >> +++ b/arch/arm/plat-samsung/dma-ops.c >> @@ -19,8 +19,8 @@ >> >> static inline bool pl330_filter(struct dma_chan *chan, void *param) >> { >> - struct dma_pl330_peri *peri = chan->private; >> - return peri->peri_id == (unsigned)param; >> + u8 *peri_id = chan->private; >> + return *peri_id == (unsigned)param; >> } > > As a word of warning - this will fail horribly if you have mixed DMA > engines in the system. While we wait for a better scheme, we really > need to sort out these filter functions properly and stop poking > about in data which may not be what we expect. > > One solution to that is to move pl330_filter() into drivers/dma/pl330.c > and have it check chan->device->dev->driver == &pl330_driver.driver > _before_ we start accessing chan->private. > > That's not a comment against your patch - you're not really changing > the brokenness of this function. It would be good to see a follow up > patch fixing it properly though. > Ok. I will prepare a patch to move the pl330_filter function into drivers/dma/pl330.c and also add the check that you have proposed. Thanks for your help. Regards, Thomas.
diff --git a/arch/arm/plat-samsung/dma-ops.c b/arch/arm/plat-samsung/dma-ops.c index 6e3d9ab..4f1430b 100644 --- a/arch/arm/plat-samsung/dma-ops.c +++ b/arch/arm/plat-samsung/dma-ops.c @@ -19,8 +19,8 @@ static inline bool pl330_filter(struct dma_chan *chan, void *param) { - struct dma_pl330_peri *peri = chan->private; - return peri->peri_id == (unsigned)param; + u8 *peri_id = chan->private; + return *peri_id == (unsigned)param; } static unsigned samsung_dmadev_request(enum dma_ch dma_ch,
With the change in dma channels private data information, the pl330 channel filter function is modified to look for a simple u8 value instead of the now unused 'struct dma_pl330_peri' value. Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org> --- arch/arm/plat-samsung/dma-ops.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)