The patch titled Documentation/DMA-API-HOWTO: add ARCH_KMALLOC_MINALIGN description has been added to the -mm tree. Its filename is documentation-dma-api-howto-add-arch_kmalloc_minalign-description.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: Documentation/DMA-API-HOWTO: add ARCH_KMALLOC_MINALIGN description From: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> Add ARCH_KMALLOC_MINALIGN description in "Platform Issues" section. Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Cc: Matt Mackall <mpm@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/DMA-API-HOWTO.txt | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff -puN Documentation/DMA-API-HOWTO.txt~documentation-dma-api-howto-add-arch_kmalloc_minalign-description Documentation/DMA-API-HOWTO.txt --- a/Documentation/DMA-API-HOWTO.txt~documentation-dma-api-howto-add-arch_kmalloc_minalign-description +++ a/Documentation/DMA-API-HOWTO.txt @@ -738,7 +738,20 @@ to "Closing". CONFIG_NEED_SG_DMA_LENGTH if the architecture supports IOMMUs (including software IOMMU). -2) More to come... +2) ARCH_KMALLOC_MINALIGN + + Architectures must ensure that kmalloc'ed buffer is + DMA-safe. Drivers and subsystems depend on it. If an architecture + isn't fully DMA-coherent (i.e. hardware doesn't ensure that data in + the CPU cache is identical to data in main memory), + ARCH_KMALLOC_MINALIGN must be set so that the memory allocator + makes sure that kmalloc'ed buffer doesn't share a cache line with + the others. See arch/arm/include/asm/cache.h as an example. + + Note that ARCH_KMALLOC_MINALIGN is about DMA memory alignment + constraints. You don't need to worry about the architecture data + alignment constraints (e.g. the alignment constraints about 64-bit + objects). Closing _ Patches currently in -mm which might be from fujita.tomonori@xxxxxxxxxxxxx are origin.patch linux-next.patch scsi-add-__init-__exit-macros-to-ibmvstgtc.patch ia64-remove-unnecessary-sync_single_range_-in-swiotlb_dma_ops.patch x86-remove-unnecessary-sync_single_range_-in-swiotlb_dma_ops.patch powerpc-remove-unnecessary-sync_single_range_-in-swiotlb_dma_ops.patch swiotlb-remove-unnecessary-swiotlb_sync_single_range_.patch dma-mapping-remove-unnecessary-sync_single_range_-in-dma_map_ops.patch documentation-add-networking-drivers-mapping-error-handling-to-dma-api-howto.patch staging-saa7134-go7007-replace-dma_sync_single-with-dma_sync_single_for_cpu.patch dma-mapping-remove-deprecated-dma_sync_single-and-dma_sync_sg-api.patch documentation-add-scsi-drivers-mapping-error-handling-to-dma-api-howto.patch documentation-update-scatterlist-struct-description-in-dma-api-howto.patch documentation-move-the-error-handling-to-the-better-place-in-dma-api-howto.patch documentation-dma-api-howto-add-arch_kmalloc_minalign-description.patch ssb-add-dma_dev-to-ssb_device-structure.patch b43legacy-replace-the-ssb_dma-api-with-the-generic-dma-api.patch b43-replace-the-ssb_dma-api-with-the-generic-dma-api.patch b44-replace-the-ssb_dma-api-with-the-generic-dma-api.patch ssb-remove-the-ssb-dma-api.patch asm-generic-remove-isa_dma_threshold-in-scatterlisth.patch asm-generic-add-need_sg_dma_length-to-define-sg_dma_len.patch x86_32-use-asm-generic-scatterlisth.patch powerpc-use-asm-generic-scatterlisth.patch alpha-use-asm-generic-scatterlisth.patch asm-generic-remove-arch_has_sg_chain-in-scatterlisth.patch avr32-use-asm-generic-scatterlisth.patch cris-use-asm-generic-scatterlisth.patch h8300-use-asm-generic-scatterlisth.patch m32r-use-use-asm-generic-scatterlisth.patch m68k-use-asm-generic-scatterlisth.patch mips-use-use-asm-generic-scatterlisth.patch xtensa-use-use-asm-generic-scatterlisth.patch blackfin-use-use-asm-generic-scatterlisth.patch frv-use-asm-generic-scatterlisth.patch mn10300-use-asm-generic-scatterlisth.patch parisc-use-asm-generic-scatterlisth.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html