On 2021-11-11 06:50, Christoph Hellwig wrote:
Add two local variables to track if we want to remap the returned address using vmap or call dma_set_uncached and use that to simplify the code flow.
I still wonder about the asymmetry between the remap and set_uncached cases WRT the memset(), which stands out even more the further we clean things up, but that's another matter.
Reviewed-by: Robin Murphy <robin.mur...@arm.com>
Signed-off-by: Christoph Hellwig <h...@lst.de> --- kernel/dma/direct.c | 48 ++++++++++++++++++++++++--------------------- 1 file changed, 26 insertions(+), 22 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index d7a489be48470..3d1718dc077e9 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -171,6 +171,7 @@ static void *dma_direct_alloc_from_pool(struct device *dev, size_t size, void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) { + bool remap = false, set_uncached = false; struct page *page; void *ret;@@ -222,9 +223,25 @@ void *dma_direct_alloc(struct device *dev, size_t size,if (!page) return NULL;- if ((IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&- !dev_is_dma_coherent(dev)) || - (IS_ENABLED(CONFIG_DMA_REMAP) && PageHighMem(page))) { + if (!dev_is_dma_coherent(dev) && IS_ENABLED(CONFIG_DMA_DIRECT_REMAP)) { + remap = true; + } else if (PageHighMem(page)) { + /* + * Depending on the cma= arguments and per-arch setup, + * dma_alloc_contiguous could return highmem pages. + * Without remapping there is no way to return them here, so + * log an error and fail. + */ + if (!IS_ENABLED(CONFIG_DMA_REMAP)) { + dev_info(dev, "Rejecting highmem page from CMA.\n"); + goto out_free_pages; + } + remap = true; + } else if (!dev_is_dma_coherent(dev) && + IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED)) + set_uncached = true; + + if (remap) { /* remove any dirty cache lines on the kernel alias */ arch_dma_prep_coherent(page, size);@@ -234,34 +251,21 @@ void *dma_direct_alloc(struct device *dev, size_t size,__builtin_return_address(0)); if (!ret) goto out_free_pages; - memset(ret, 0, size); - goto done; - } - - if (PageHighMem(page)) { - /* - * Depending on the cma= arguments and per-arch setup - * dma_alloc_contiguous could return highmem pages. - * Without remapping there is no way to return them here, - * so log an error and fail. - */ - dev_info(dev, "Rejecting highmem page from CMA.\n"); - goto out_free_pages; + } else { + ret = page_address(page); + if (dma_set_decrypted(dev, ret, size)) + goto out_free_pages; }- ret = page_address(page);- if (dma_set_decrypted(dev, ret, size)) - goto out_free_pages; memset(ret, 0, size);- if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&- !dev_is_dma_coherent(dev)) { + if (set_uncached) { arch_dma_prep_coherent(page, size); ret = arch_dma_set_uncached(ret, size); if (IS_ERR(ret)) goto out_encrypt_pages; } -done: + *dma_handle = phys_to_dma_direct(dev, page_to_phys(page)); return ret;
_______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
