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Tue, 12 May 2020 09:01:07 +0000 (GMT) X-AuditID: cbfec7f4-0cbff7000001ed07-6d-5eba65d38a59 Received: from eusmtip1.samsung.com ( [203.254.199.221]) by eusmgms2.samsung.com (EUCPMTA) with SMTP id 5C.E2.07950.3D56ABE5; Tue, 12 May 2020 10:01:07 +0100 (BST) Received: from AMDC2765.digital.local (unknown [106.120.51.73]) by eusmtip1.samsung.com (KnoxPortal) with ESMTPA id 20200512090107eusmtip1b2037aa85d846147c42bf55aa7eae1c6~OPFf5hCsF0782807828eusmtip1S; Tue, 12 May 2020 09:01:07 +0000 (GMT) From: Marek Szyprowski To: dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 01/38] dma-mapping: add generic helpers for mapping sgtable objects Date: Tue, 12 May 2020 11:00:21 +0200 Message-Id: <20200512090058.14910-1-m.szyprowski@samsung.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200512085710.14688-1-m.szyprowski@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrCKsWRmVeSWpSXmKPExsWy7djPc7pXUnfFGXxrZ7ToPXeSyWLjjPWs Fv+3TWS2uPL1PZvFytVHmSwW7Le2+HLlIZPFpsfXWC0u75rDZrH2yF12i4MfnrA6cHusmbeG 0WPvtwUsHtu/PWD1uN99nMlj85J6j9v/HjN7TL6xnNFj980GNo++LasYPT5vkgvgiuKySUnN ySxLLdK3S+DKaNy8g6nguGrF5edzmRoY78l1MXJySAiYSDQ96mTsYuTiEBJYwSjRu3MqE4Tz hVHi3rUNzBDOZ0aJHc39jDAtnf+vQrUsZ5RYNGErO0gCrGXmPycQm03AUKLrbRcbiC0i0Moo caKXB8RmFpjBJHH0dSmILSwQIbHo4QWwoSwCqhL7Ds5nBbF5BWwlmvp7oZbJS6zecIAZxOYU sJPofPiDHSK+jl1i53Z/CNtFovlcPwuELSzx6vgWqBoZidOTe1hADpUQaGaUeHhuLTuE08Mo cblpBtQGa4k7534BXcoBdJ2mxPpd+hBhR4ldx5+wg4QlBPgkbrwVhLifT2LStunMEGFeiY42 IYhqNYlZx9fBrT144RJUiYfEgUtRkNCZyCjxe4HOBEb5WQirFjAyrmIUTy0tzk1PLTbKSy3X K07MLS7NS9dLzs/dxAhMO6f/Hf+yg3HXn6RDjAIcjEo8vAYGO+OEWBPLiitzDzFKcDArifC2 ZAKFeFMSK6tSi/Lji0pzUosPMUpzsCiJ8xovehkrJJCeWJKanZpakFoEk2Xi4JRqYLQQ05pi 1ySsm5x2QfVjkKD6PrGs+x4OSTW8T3fo97Veyj/Hwqr6/KS6W03visDHz88/Xq0o1vBIIL61 SU7jnjPXfpl38cuzriXvPuf0sLTAPK03s+XD3tVlVn2KbT6PQ5vX1q12fllt9sqnOHXLvItd TWtyYy653tQT623id1mwXXafb36hEktxRqKhFnNRcSIA84/nVzcDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFupkkeLIzCtJLcpLzFFi42I5/e/4Xd3LqbviDD4s0rHoPXeSyWLjjPWs Fv+3TWS2uPL1PZvFytVHmSwW7Le2+HLlIZPFpsfXWC0u75rDZrH2yF12i4MfnrA6cHusmbeG 0WPvtwUsHtu/PWD1uN99nMlj85J6j9v/HjN7TL6xnNFj980GNo++LasYPT5vkgvgitKzKcov LUlVyMgvLrFVija0MNIztLTQMzKx1DM0No+1MjJV0rezSUnNySxLLdK3S9DLaNy8g6nguGrF 5edzmRoY78l1MXJySAiYSHT+v8rYxcjFISSwlFHiy+qJjBAJGYmT0xpYIWxhiT/Xutggij4x SqxdcpMJJMEmYCjR9RYiISLQySgxrfsjO4jDLDCPSWLRw0NADgeHsECYxJbdHCANLAKqEvsO zgebyitgK9HU3wu1TV5i9YYDzCA2p4CdROfDH+wgthBQzcO+W6wTGPkWMDKsYhRJLS3OTc8t NtIrTswtLs1L10vOz93ECIyGbcd+btnB2PUu+BCjAAejEg9vh9HOOCHWxLLiytxDjBIczEoi vC2ZQCHelMTKqtSi/Pii0pzU4kOMpkBHTWSWEk3OB0ZqXkm8oamhuYWlobmxubGZhZI4b4fA wRghgfTEktTs1NSC1CKYPiYOTqkGRu/olx++8ud2FykYSVVznPJTMt95RLdK7sovhzUBNzID HhTFlpatllu3Z0uRxKG7fDzz5jNUvypSYP73+Sc7y1vVm9PuJS/RVdzBd6grodS+9Pw8zS77 ae+VrO3uXFW+1ZJ4K0HHituMc2X4Fl6O596Mx7a0a2ruW7Yudr4LE88S3jVrpgW6KLEUZyQa ajEXFScCAIf2MGacAgAA X-CMS-MailID: 20200512090107eucas1p13a38ce5ce4c15cd0033acaea7b26c9b0 X-Msg-Generator: CA X-RootMTR: 20200512090107eucas1p13a38ce5ce4c15cd0033acaea7b26c9b0 X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200512090107eucas1p13a38ce5ce4c15cd0033acaea7b26c9b0 References: <20200512085710.14688-1-m.szyprowski@samsung.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200512_020109_957590_258EFFD5 X-CRM114-Status: GOOD ( 17.13 ) X-Spam-Score: -5.4 (-----) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-5.4 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [210.118.77.12 listed in list.dnswl.org] -0.0 SPF_HELO_PASS SPF: HELO matches SPF record -0.0 SPF_PASS SPF: sender matches SPF record 0.0 RCVD_IN_MSPIKE_H3 RBL: Good reputation (+3) [210.118.77.12 listed in wl.mailspike.net] 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain 0.0 RCVD_IN_MSPIKE_WL Mailspike good senders -0.2 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Bartlomiej Zolnierkiewicz , David Airlie , Daniel Vetter , Robin Murphy , Christoph Hellwig , linux-arm-kernel@lists.infradead.org, Marek Szyprowski MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org struct sg_table is a common structure used for describing a memory buffer. It consists of a scatterlist with memory pages and DMA addresses (sgl entry), as well as the number of scatterlist entries: CPU pages (orig_nents entry) and DMA mapped pages (nents entry). It turned out that it was a common mistake to misuse nents and orig_nents entries, calling DMA-mapping functions with a wrong number of entries or ignoring the number of mapped entries returned by the dma_map_sg function. To avoid such issues, lets introduce a common wrappers operating directly on the struct sg_table objects, which take care of the proper use of the nents and orig_nents entries. Signed-off-by: Marek Szyprowski Reviewed-by: Christoph Hellwig Reviewed-by: Robin Murphy --- For more information, see '[PATCH v4 00/38] DRM: fix struct sg_table nents vs. orig_nents misuse' thread: https://lore.kernel.org/dri-devel/20200512085710.14688-1-m.szyprowski@samsung.com/T/ --- include/linux/dma-mapping.h | 79 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index b43116a..88f01cc 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -609,6 +609,85 @@ static inline void dma_sync_single_range_for_device(struct device *dev, return dma_sync_single_for_device(dev, addr + offset, size, dir); } +/** + * dma_map_sgtable - Map the given buffer for the DMA operations + * @dev: The device to perform a DMA operation + * @sgt: The sg_table object describing the buffer + * @dir: DMA direction + * @attrs: Optional DMA attributes for the map operation + * + * Maps a buffer described by a scatterlist stored in the given sg_table + * object for the @dir DMA operation by the @dev device. After success + * the ownership for the buffer is transferred to the DMA domain. One has + * to call dma_sync_sgtable_for_cpu() or dma_unmap_sgtable() to move the + * ownership of the buffer back to the CPU domain before touching the + * buffer by the CPU. + * Returns 0 on success or -EINVAL on error during mapping the buffer. + */ +static inline int dma_map_sgtable(struct device *dev, struct sg_table *sgt, + enum dma_data_direction dir, unsigned long attrs) +{ + int n = dma_map_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs); + + if (n > 0) { + sgt->nents = n; + return 0; + } + return -EINVAL; +} + +/** + * dma_unmap_sgtable - Unmap the given buffer for the DMA operations + * @dev: The device to perform a DMA operation + * @sgt: The sg_table object describing the buffer + * @dir: DMA direction + * @attrs: Optional DMA attributes for the map operation + * + * Unmaps a buffer described by a scatterlist stored in the given sg_table + * object for the @dir DMA operation by the @dev device. After this function + * the ownership of the buffer is transferred back to the CPU domain. + */ +static inline void dma_unmap_sgtable(struct device *dev, struct sg_table *sgt, + enum dma_data_direction dir, unsigned long attrs) +{ + dma_unmap_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs); +} + +/** + * dma_sync_sgtable_for_cpu - Synchronize the given buffer for the CPU access + * @dev: The device to perform a DMA operation + * @sgt: The sg_table object describing the buffer + * @dir: DMA direction + * + * Performs the needed cache synchronization and moves the ownership of the + * buffer back to the CPU domain, so it is safe to perform any access to it + * by the CPU. Before doing any further DMA operations, one has to transfer + * the ownership of the buffer back to the DMA domain by calling the + * dma_sync_sgtable_for_device(). + */ +static inline void dma_sync_sgtable_for_cpu(struct device *dev, + struct sg_table *sgt, enum dma_data_direction dir) +{ + dma_sync_sg_for_cpu(dev, sgt->sgl, sgt->orig_nents, dir); +} + +/** + * dma_sync_sgtable_for_device - Synchronize the given buffer for the DMA + * @dev: The device to perform a DMA operation + * @sgt: The sg_table object describing the buffer + * @dir: DMA direction + * + * Performs the needed cache synchronization and moves the ownership of the + * buffer back to the DMA domain, so it is safe to perform the DMA operation. + * Once finished, one has to call dma_sync_sgtable_for_cpu() or + * dma_unmap_sgtable(). + */ +static inline void dma_sync_sgtable_for_device(struct device *dev, + struct sg_table *sgt, enum dma_data_direction dir) +{ + dma_sync_sg_for_device(dev, sgt->sgl, sgt->orig_nents, dir); +} + #define dma_map_single(d, a, s, r) dma_map_single_attrs(d, a, s, r, 0) #define dma_unmap_single(d, a, s, r) dma_unmap_single_attrs(d, a, s, r, 0) #define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, 0)