Re: [PATCH v6 15/20] iommu/dma: Check atomic pool allocation result directly
From: Petr Tesarik <hidden>
Date: 2026-06-09 13:27:01
Also in:
linux-arm-kernel, linux-coco, linux-iommu, linux-s390, lkml
On Thu, 4 Jun 2026 14:09:54 +0530 "Aneesh Kumar K.V (Arm)" [off-list ref] wrote:
The non-blocking, non-coherent allocation path uses dma_alloc_from_pool(),
which returns the allocated page and fills cpu_addr only on success.
Do not rely on cpu_addr to detect allocation failure in this path. Check
the returned page directly before using it for the IOMMU mapping.
Fixes: 9420139f516d ("dma-pool: fix coherent pool allocations for IOMMU mappings")
Tested-by: Michael Kelley <redacted>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>Reviewed-by: Petr Tesarik <redacted> Petr T
quoted hunk ↗ jump to hunk
--- drivers/iommu/dma-iommu.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 725c7adb0a8d..52c599f4472c 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c@@ -1671,13 +1671,16 @@ void *iommu_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, } if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && - !gfpflags_allow_blocking(gfp) && !coherent) + !gfpflags_allow_blocking(gfp) && !coherent) { page = dma_alloc_from_pool(dev, PAGE_ALIGN(size), &cpu_addr, gfp, attrs, NULL); - else + if (!page) + return NULL; + } else { cpu_addr = iommu_dma_alloc_pages(dev, size, &page, gfp, attrs); - if (!cpu_addr) - return NULL; + if (!cpu_addr) + return NULL; + } *handle = __iommu_dma_map(dev, page_to_phys(page), size, ioprot, dev->coherent_dma_mask);