On Thu, 23 Jan 2014 15:51:31 +0530 Prabhakar Lad <prabhakar.cse...@gmail.com> wrote:
> Hi Sachin, > > On Thu, Jan 23, 2014 at 3:38 PM, Sachin Kamat <sachin.ka...@linaro.org> wrote: > > Hi Prabhakar, > > > > On 23 January 2014 15:26, Prabhakar Lad <prabhakar.cse...@gmail.com> wrote: > >> From: "Lad, Prabhakar" <prabhakar.cse...@gmail.com> > >> > >> In the gen_pool_dma_alloc() the dma pointer can be NULL > >> and while assigning gen_pool_virt_to_phys(pool, vaddr) to > >> dma caused the following crash on da850 evm, > >> > > [snip] > >> > >> Signed-off-by: Lad, Prabhakar <prabhakar.cse...@gmail.com> > >> --- > >> lib/genalloc.c | 3 ++- > >> 1 file changed, 2 insertions(+), 1 deletion(-) > >> > >> diff --git a/lib/genalloc.c b/lib/genalloc.c > >> index dda3116..f48163f 100644 > >> --- a/lib/genalloc.c > >> +++ b/lib/genalloc.c > >> @@ -334,7 +334,8 @@ void *gen_pool_dma_alloc(struct gen_pool *pool, size_t > >> size, dma_addr_t *dma) > >> if (!vaddr) > >> return NULL; > >> > >> - *dma = gen_pool_virt_to_phys(pool, vaddr); > >> + if (dma) > >> + *dma = gen_pool_virt_to_phys(pool, vaddr); > > > > Wouldn't it be better to return (with error/message) if dma is NULL > > rather than silently ignore it? > > > I am not sure if returning here with error is OK, > may be just adding a warning message could be OK ? The patch look OK as-is to me. `dma' is a second return value from gen_pool_dma_alloc() and this patch extends the gen_pool_dma_alloc() interface by making that return value optional. That's good for callers who don't want the physical address, and they can call gen_pool_virt_to_phys() at a later time to get the physical address anyway. >From my reading, 3.13.x kernels will need this patch. I suppose we should document the API change: --- a/lib/genalloc.c~lib-genallocc-add-check-gen_pool_dma_alloc-if-dma-pointer-is-not-null-fix +++ a/lib/genalloc.c @@ -316,7 +316,7 @@ EXPORT_SYMBOL(gen_pool_alloc); * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage * @pool: pool to allocate from * @size: number of bytes to allocate from the pool - * @dma: dma-view physical address + * @dma: dma-view physical address return value. Use NULL if unneeded. * * Allocate the requested number of bytes from the specified pool. * Uses the pool allocation function (with first-fit algorithm by default). _ _______________________________________________ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
