| Message ID | 20210723214031.3251801-5-atish.patra@wdc.com |
|---|---|
| State | New |
| Headers | show |
| Series | Support non-coherent DMA on RISC-V using a global pool | expand |
On Fri, Jul 23, 2021 at 02:40:30PM -0700, Atish Patra wrote: > DMA_GLOBAL_POOL config may be enabled for platforms where global pool is > not supported because a generic defconfig is expected to boot on different > platforms. Specifically, some RISC-V platforms may use global pool for > non-coherent devices while some other platforms are completely coherent. > However, it is expected that single kernel image must boot on all the > platforms. > > Continue the dma direct allocation if a allocation from global pool failed. > This indicates that the platform is relying on some other method (direct > remap) or just have coherent devices. > > Signed-off-by: Atish Patra <atish.patra@wdc.com> > --- > kernel/dma/direct.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c > index d1d0258ed6d0..984ea776f099 100644 > --- a/kernel/dma/direct.c > +++ b/kernel/dma/direct.c > @@ -161,8 +161,11 @@ void *dma_direct_alloc(struct device *dev, size_t size, > return arch_dma_alloc(dev, size, dma_handle, gfp, attrs); > > if (IS_ENABLED(CONFIG_DMA_GLOBAL_POOL) && > - !dev_is_dma_coherent(dev)) > - return dma_alloc_from_global_coherent(dev, size, dma_handle); > + !dev_is_dma_coherent(dev)) { > + ret = dma_alloc_from_global_coherent(dev, size, dma_handle); > + if (ret) > + return ret; This will now silently return normal non-cache coherent memory when the global pool allocation fails, and thus is completely broken.
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index d1d0258ed6d0..984ea776f099 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -161,8 +161,11 @@ void *dma_direct_alloc(struct device *dev, size_t size, return arch_dma_alloc(dev, size, dma_handle, gfp, attrs); if (IS_ENABLED(CONFIG_DMA_GLOBAL_POOL) && - !dev_is_dma_coherent(dev)) - return dma_alloc_from_global_coherent(dev, size, dma_handle); + !dev_is_dma_coherent(dev)) { + ret = dma_alloc_from_global_coherent(dev, size, dma_handle); + if (ret) + return ret; + } /* * Remapping or decrypting memory may block. If either is required and
DMA_GLOBAL_POOL config may be enabled for platforms where global pool is not supported because a generic defconfig is expected to boot on different platforms. Specifically, some RISC-V platforms may use global pool for non-coherent devices while some other platforms are completely coherent. However, it is expected that single kernel image must boot on all the platforms. Continue the dma direct allocation if a allocation from global pool failed. This indicates that the platform is relying on some other method (direct remap) or just have coherent devices. Signed-off-by: Atish Patra <atish.patra@wdc.com> --- kernel/dma/direct.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)