This is a note to let you know that I've just added the patch titled dma-direct: don't fail on highmem CMA pages in dma_direct_alloc_pages to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dma-direct-don-t-fail-on-highmem-cma-pages-in-dma_di.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit c4ef1bbb5af8d1cb9b02fd856218ae17eae9dfeb Author: Christoph Hellwig <hch@xxxxxx> Date: Sat Apr 23 19:20:24 2022 +0200 dma-direct: don't fail on highmem CMA pages in dma_direct_alloc_pages [ Upstream commit 92826e967535db2eb117db227b1191aaf98e4bb3 ] When dma_direct_alloc_pages encounters a highmem page it just gives up currently. But what we really should do is to try memory using the page allocator instead - without this platforms with a global highmem CMA pool will fail all dma_alloc_pages allocations. Fixes: efa70f2fdc84 ("dma-mapping: add a new dma_alloc_pages API") Reported-by: Mark O'Neill <mao@xxxxxxxxxxxxxxxxxx> Signed-off-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index ddaac01f2cba..a1573ed2ea18 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -85,7 +85,7 @@ static void __dma_direct_free_pages(struct device *dev, struct page *page, } static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, - gfp_t gfp) + gfp_t gfp, bool allow_highmem) { int node = dev_to_node(dev); struct page *page = NULL; @@ -106,9 +106,12 @@ static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, } page = dma_alloc_contiguous(dev, size, gfp); - if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) { - dma_free_contiguous(dev, page, size); - page = NULL; + if (page) { + if (!dma_coherent_ok(dev, page_to_phys(page), size) || + (!allow_highmem && PageHighMem(page))) { + dma_free_contiguous(dev, page, size); + page = NULL; + } } again: if (!page) @@ -154,7 +157,7 @@ static void *dma_direct_alloc_no_mapping(struct device *dev, size_t size, { struct page *page; - page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO); + page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true); if (!page) return NULL; @@ -209,7 +212,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); /* we always manually zero the memory once we are done */ - page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO); + page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true); if (!page) return NULL; @@ -335,19 +338,9 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size, !is_swiotlb_for_alloc(dev)) return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); - page = __dma_direct_alloc_pages(dev, size, gfp); + page = __dma_direct_alloc_pages(dev, size, gfp, false); if (!page) return NULL; - 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; - } ret = page_address(page); if (force_dma_unencrypted(dev)) {