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(109-252-150-34.dynamic.spd-mgts.ru [109.252.150.34]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dmitry.osipenko) by madras.collabora.co.uk (Postfix) with ESMTPSA id EAF2C6606E70; Mon, 29 May 2023 23:46:14 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1685400376; bh=0gUDR36aFi1An+7dulD3u+YxPIoB7pS3+8FHmbgN34M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kFTQwSvRp+7rcxbKYy6ILZdSTky+OhBr8/U7fMcRcLjIb3k1sNvx7jZCvG8ZzX6PS Vgze+gX3jXv24R9Afi3K7GzE0N44iN1GjkHi74MHVeSmzi6inak8ULRq8VqzisE9j5 Y3uRDYlrv+IFub32VPIJHlHRhryBo/GIkU1Wk2M2xvbHejtxd7fS75jOrFGTmbeCgX 5K8Ub8V1bMhPLN8yuJdIyLWs4j/vAu3GesLHrBXrqMO9WRPyEr2q6og0D1iskbt67U w4rYpzoLcGZlmLsM+trMh15Lb60ILuE4pZz6OOJfQtm3zNPV6IaA23aobnL9PFsh1p KVuT6Y9hWOf+A== From: Dmitry Osipenko To: Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= , Benjamin Gaignard , Brian Starkey , John Stultz , Gerd Hoffmann , Daniel Vetter , Jani Nikula , Arnd Bergmann , Thomas Zimmermann , Tomi Valkeinen , Thierry Reding , Tomasz Figa , Marek Szyprowski , Mauro Carvalho Chehab , Emil Velikov Cc: linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-tegra@vger.kernel.org, kernel@collabora.com Subject: [PATCH v4 5/6] dma-buf: Change locking policy for mmap() Date: Tue, 30 May 2023 01:39:34 +0300 Message-Id: <20230529223935.2672495-6-dmitry.osipenko@collabora.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230529223935.2672495-1-dmitry.osipenko@collabora.com> References: <20230529223935.2672495-1-dmitry.osipenko@collabora.com> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1767270729022701551?= X-GMAIL-MSGID: =?utf-8?q?1767270729022701551?= Change locking policy of mmap() callback, making exporters responsible for handling dma-buf reservation locking. Previous locking policy stated that dma-buf is locked for both importers and exporters by the dma-buf core, which caused a deadlock problem for DRM drivers in a case of self-imported dma-bufs which required to take the lock from the DRM exporter side. Reviewed-by: Emil Velikov Signed-off-by: Dmitry Osipenko --- drivers/dma-buf/dma-buf.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index aa4ea8530cb3..21916bba77d5 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -131,7 +131,6 @@ static struct file_system_type dma_buf_fs_type = { static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) { struct dma_buf *dmabuf; - int ret; if (!is_dma_buf_file(file)) return -EINVAL; @@ -147,11 +146,7 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) dmabuf->size >> PAGE_SHIFT) return -EINVAL; - dma_resv_lock(dmabuf->resv, NULL); - ret = dmabuf->ops->mmap(dmabuf, vma); - dma_resv_unlock(dmabuf->resv); - - return ret; + return dmabuf->ops->mmap(dmabuf, vma); } static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence) @@ -850,6 +845,7 @@ static struct sg_table * __map_dma_buf(struct dma_buf_attachment *attach, * - &dma_buf_ops.release() * - &dma_buf_ops.begin_cpu_access() * - &dma_buf_ops.end_cpu_access() + * - &dma_buf_ops.mmap() * * 2. These &dma_buf_ops callbacks are invoked with locked dma-buf * reservation and exporter can't take the lock: @@ -858,7 +854,6 @@ static struct sg_table * __map_dma_buf(struct dma_buf_attachment *attach, * - &dma_buf_ops.unpin() * - &dma_buf_ops.map_dma_buf() * - &dma_buf_ops.unmap_dma_buf() - * - &dma_buf_ops.mmap() * - &dma_buf_ops.vmap() * - &dma_buf_ops.vunmap() * @@ -1463,8 +1458,6 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_end_cpu_access, DMA_BUF); int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, unsigned long pgoff) { - int ret; - if (WARN_ON(!dmabuf || !vma)) return -EINVAL; @@ -1485,11 +1478,7 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, vma_set_file(vma, dmabuf->file); vma->vm_pgoff = pgoff; - dma_resv_lock(dmabuf->resv, NULL); - ret = dmabuf->ops->mmap(dmabuf, vma); - dma_resv_unlock(dmabuf->resv); - - return ret; + return dmabuf->ops->mmap(dmabuf, vma); } EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, DMA_BUF);