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Thu, 15 Jul 2021 10:46:04 -0600 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.92) (envelope-from ) id 1m44Up-0001nr-Se; Thu, 15 Jul 2021 10:45:59 -0600 From: Logan Gunthorpe To: linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, iommu@lists.linux-foundation.org, linux-parisc@vger.kernel.org, xen-devel@lists.xenproject.org Cc: Christoph Hellwig , Marek Szyprowski , Robin Murphy , Stephen Bates , Martin Oliveira , Logan Gunthorpe Date: Thu, 15 Jul 2021 10:45:44 -0600 Message-Id: <20210715164544.6827-17-logang@deltatee.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210715164544.6827-1-logang@deltatee.com> References: <20210715164544.6827-1-logang@deltatee.com> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 172.16.1.31 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-parisc@vger.kernel.org, xen-devel@lists.xenproject.org, hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com, sbates@raithlin.com, martin.oliveira@eideticom.com, logang@deltatee.com X-SA-Exim-Mail-From: gunthorp@deltatee.com Subject: [PATCH v1 16/16] dma-mapping: Disallow .map_sg operations from returning zero on error X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210715_094605_116541_83A06098 X-CRM114-Status: GOOD ( 15.56 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Now that all the .map_sg operations have been converted to returning proper error codes, drop the code to handle a zero return value, add a warning if a zero is returned and update the comment for the map_sg operation. Signed-off-by: Logan Gunthorpe --- include/linux/dma-map-ops.h | 8 +++----- kernel/dma/mapping.c | 6 +++--- 2 files changed, 6 insertions(+), 8 deletions(-) diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h index eaa969be8284..f299bc1e317b 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -42,11 +42,9 @@ struct dma_map_ops { unsigned long attrs); /* * map_sg should return a negative error code on error. - * dma_map_sgtable() will return the error code returned and convert - * a zero return (for legacy implementations) into -EINVAL. - * - * dma_map_sg() will always return zero on any negative or zero - * return to satisfy its own calling convention. + * dma_map_sgtable() will return the error code returned by the + * operation and dma_map_sg() will always convert any error to zero + * to satisfy its own calling convention. */ int (*map_sg)(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, unsigned long attrs); diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 30f89d244566..978a6a16aaf7 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -194,6 +194,8 @@ static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, else ents = ops->map_sg(dev, sg, nents, dir, attrs); + WARN_ON_ONCE(ents == 0); + if (ents > 0) debug_dma_map_sg(dev, sg, nents, ents, dir); @@ -251,9 +253,7 @@ int dma_map_sgtable(struct device *dev, struct sg_table *sgt, int nents; nents = __dma_map_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs); - if (nents == 0) - return -EINVAL; - else if (nents < 0) + if (nents < 0) return nents; sgt->nents = nents;