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[211.19.85.30]) by smtp.gmail.com with ESMTPSA id q144sm10986713pfc.103.2019.06.16.02.17.27 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Sun, 16 Jun 2019 02:17:28 -0700 (PDT) Date: Sun, 16 Jun 2019 18:17:24 +0900 From: Stafford Horne To: Christoph Hellwig Cc: Vineet Gupta , Jonas Bonn , Stefan Kristiansson , Helge Deller , Vladimir Murzin , linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linux-xtensa@linux-xtensa.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/7] openrisc: remove the partial DMA_ATTR_NON_CONSISTENT support Message-ID: <20190616091724.GL2358@lianli.shorne-pla.net> References: <20190614144431.21760-1-hch@lst.de> <20190614144431.21760-4-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190614144431.21760-4-hch@lst.de> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org On Fri, Jun 14, 2019 at 04:44:27PM +0200, Christoph Hellwig wrote: > The openrisc DMA code supports DMA_ATTR_NON_CONSISTENT allocations, but > does not provide a cache_sync operation. This means any user of it > will never be able to actually transfer cache ownership and thus cause > coherency bugs. The below looks good. I am always happy to what looks like legacy copy & paste cruft. Acked-by: Stafford Horne > Signed-off-by: Christoph Hellwig > --- > arch/openrisc/kernel/dma.c | 22 +++++++++------------- > 1 file changed, 9 insertions(+), 13 deletions(-) > > diff --git a/arch/openrisc/kernel/dma.c b/arch/openrisc/kernel/dma.c > index f79457cb3741..9f25fd0fbb5d 100644 > --- a/arch/openrisc/kernel/dma.c > +++ b/arch/openrisc/kernel/dma.c > @@ -98,15 +98,13 @@ arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, > > va = (unsigned long)page; > > - if ((attrs & DMA_ATTR_NON_CONSISTENT) == 0) { > - /* > - * We need to iterate through the pages, clearing the dcache for > - * them and setting the cache-inhibit bit. > - */ > - if (walk_page_range(va, va + size, &walk)) { > - free_pages_exact(page, size); > - return NULL; > - } > + /* > + * We need to iterate through the pages, clearing the dcache for > + * them and setting the cache-inhibit bit. > + */ > + if (walk_page_range(va, va + size, &walk)) { > + free_pages_exact(page, size); > + return NULL; > } > > return (void *)va; > @@ -122,10 +120,8 @@ arch_dma_free(struct device *dev, size_t size, void *vaddr, > .mm = &init_mm > }; > > - if ((attrs & DMA_ATTR_NON_CONSISTENT) == 0) { > - /* walk_page_range shouldn't be able to fail here */ > - WARN_ON(walk_page_range(va, va + size, &walk)); > - } > + /* walk_page_range shouldn't be able to fail here */ > + WARN_ON(walk_page_range(va, va + size, &walk)); > > free_pages_exact(vaddr, size); > } > -- > 2.20.1 >