From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from wout2-smtp.messagingengine.com ([64.147.123.25]:54317 "EHLO wout2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726396AbeHDJ7r (ORCPT ); Sat, 4 Aug 2018 05:59:47 -0400 Subject: FAILED: patch "[PATCH] ARC: dma [non IOC]: fix arc_dma_sync_single_for_(device|cpu)" failed to apply to 4.17-stable tree To: Eugeniy.Paltsev@synopsys.com, vgupta@synopsys.com Cc: From: Date: Sat, 04 Aug 2018 09:59:58 +0200 Message-ID: <153336959847208@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 4.17-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From 4c612add7b18844ddd733ebdcbe754520155999b Mon Sep 17 00:00:00 2001 From: Eugeniy Paltsev Date: Tue, 24 Jul 2018 17:13:02 +0300 Subject: [PATCH] ARC: dma [non IOC]: fix arc_dma_sync_single_for_(device|cpu) ARC backend for dma_sync_single_for_(device|cpu) was broken as it was not honoring the @dir argument and simply forcing it based on the call: - arc_dma_sync_single_for_device(dir) assumed DMA_TO_DEVICE (cache wback) - arc_dma_sync_single_for_cpu(dir) assumed DMA_FROM_DEVICE (cache inv) This is not true given the DMA API programming model and has been discussed here [1] in some detail. Interestingly while the deficiency has been there forever, it only started showing up after 4.17 dma common ops rework, commit a8eb92d02dd7 ("arc: fix arc_dma_{map,unmap}_page") which wired up these calls under the more commonly used dma_map_page API triggering the issue. [1]: https://lkml.org/lkml/2018/5/18/979 Fixes: commit a8eb92d02dd7 ("arc: fix arc_dma_{map,unmap}_page") Cc: stable@kernel.org # v4.17+ Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta [vgupta: reworked changelog] diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c index 8c1071840979..ec47e6079f5d 100644 --- a/arch/arc/mm/dma.c +++ b/arch/arc/mm/dma.c @@ -129,14 +129,59 @@ int arch_dma_mmap(struct device *dev, struct vm_area_struct *vma, return ret; } +/* + * Cache operations depending on function and direction argument, inspired by + * https://lkml.org/lkml/2018/5/18/979 + * "dma_sync_*_for_cpu and direction=TO_DEVICE (was Re: [PATCH 02/20] + * dma-mapping: provide a generic dma-noncoherent implementation)" + * + * | map == for_device | unmap == for_cpu + * |---------------------------------------------------------------- + * TO_DEV | writeback writeback | none none + * FROM_DEV | invalidate invalidate | invalidate* invalidate* + * BIDIR | writeback+inv writeback+inv | invalidate invalidate + * + * [*] needed for CPU speculative prefetches + * + * NOTE: we don't check the validity of direction argument as it is done in + * upper layer functions (in include/linux/dma-mapping.h) + */ + void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr, size_t size, enum dma_data_direction dir) { - dma_cache_wback(paddr, size); + switch (dir) { + case DMA_TO_DEVICE: + dma_cache_wback(paddr, size); + break; + + case DMA_FROM_DEVICE: + dma_cache_inv(paddr, size); + break; + + case DMA_BIDIRECTIONAL: + dma_cache_wback_inv(paddr, size); + break; + + default: + break; + } } void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr, size_t size, enum dma_data_direction dir) { - dma_cache_inv(paddr, size); + switch (dir) { + case DMA_TO_DEVICE: + break; + + /* FROM_DEVICE invalidate needed if speculative CPU prefetch only */ + case DMA_FROM_DEVICE: + case DMA_BIDIRECTIONAL: + dma_cache_inv(paddr, size); + break; + + default: + break; + } }