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Tue, 3 Jun 2025 17:53:50 +0800 From: wangtao To: , , , , , , , , CC: , , , , , , , , , , , , , , , , wangtao Subject: [PATCH v4 2/4] dmabuf: Implement copy_file_range callback for dmabuf direct I/O prep Date: Tue, 3 Jun 2025 17:52:43 +0800 Message-ID: <20250603095245.17478-3-tao.wangtao@honor.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20250603095245.17478-1-tao.wangtao@honor.com> References: <20250603095245.17478-1-tao.wangtao@honor.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.144.18.117] X-ClientProxiedBy: w002.hihonor.com (10.68.28.120) To a010.hihonor.com (10.68.16.52) X-Rspam-User: X-Rspamd-Queue-Id: 7A8C5C0004 X-Rspamd-Server: rspam09 X-Stat-Signature: dbc88i7asjcodqpkbinyytj8x1pux647 X-HE-Tag: 1748944434-685489 X-HE-Meta: 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 hv7Ux3G8 +p2W1ydKz+uZU4KqTXVbmFUsrKVlSXHxAkBtbRd4KQS0VzGM48ZaqAFJRpqcBVKHNTFNU3rIbHtsY7sxHv3c35ieVIjWBGmiXeVLP9Gw1gi6TnOXdaKbd2PQ9Hhq9JJfvFnyr/d0fJYdd2TLozaY+D/GMS5qiLKWy7xyL5d4kBROMTQG8bIcRUlcQIXw5kw5cMK+rQ9mtj2S68WXXchYBmB6s0bG0q2qBYqPeq3Um0PpusTaBZicGcCHQH3C/xnAHh50+ITdnk6BhzLtpY/DzHQbJIXR8E9eoWQ+awPtcjnEfxaV8v/BqpLtXSUyI+XlhB69NojcgQ5Jnr+8iMy0sszQKIkTPBhLsSnw3rjhXVxdEWw/LGB6RQ9Uz49vkmzqpkpbRCnpyYWCf88J02JlNwBH4IQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: First determine if dmabuf reads from or writes to the file. Then call exporter's rw_file callback function. Signed-off-by: wangtao --- drivers/dma-buf/dma-buf.c | 32 ++++++++++++++++++++++++++++++++ include/linux/dma-buf.h | 16 ++++++++++++++++ 2 files changed, 48 insertions(+) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 5baa83b85515..fc9bf54c921a 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -523,7 +523,38 @@ static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file) spin_unlock(&dmabuf->name_lock); } +static ssize_t dma_buf_rw_file(struct dma_buf *dmabuf, loff_t my_pos, + struct file *file, loff_t pos, size_t count, bool is_write) +{ + if (!dmabuf->ops->rw_file) + return -EINVAL; + + if (my_pos >= dmabuf->size) + count = 0; + else + count = min_t(size_t, count, dmabuf->size - my_pos); + if (!count) + return 0; + + return dmabuf->ops->rw_file(dmabuf, my_pos, file, pos, count, is_write); +} + +static ssize_t dma_buf_copy_file_range(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + size_t count, unsigned int flags) +{ + if (is_dma_buf_file(file_in) && file_out->f_op->write_iter) + return dma_buf_rw_file(file_in->private_data, pos_in, + file_out, pos_out, count, true); + else if (is_dma_buf_file(file_out) && file_in->f_op->read_iter) + return dma_buf_rw_file(file_out->private_data, pos_out, + file_in, pos_in, count, false); + else + return -EINVAL; +} + static const struct file_operations dma_buf_fops = { + .fop_flags = FOP_MEMORY_FILE, .release = dma_buf_file_release, .mmap = dma_buf_mmap_internal, .llseek = dma_buf_llseek, @@ -531,6 +562,7 @@ static const struct file_operations dma_buf_fops = { .unlocked_ioctl = dma_buf_ioctl, .compat_ioctl = compat_ptr_ioctl, .show_fdinfo = dma_buf_show_fdinfo, + .copy_file_range = dma_buf_copy_file_range, }; /* diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 36216d28d8bd..d3636e985399 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -22,6 +22,7 @@ #include #include #include +#include struct device; struct dma_buf; @@ -285,6 +286,21 @@ struct dma_buf_ops { int (*vmap)(struct dma_buf *dmabuf, struct iosys_map *map); void (*vunmap)(struct dma_buf *dmabuf, struct iosys_map *map); + + /** + * @rw_file: + * + * If an Exporter needs to support Direct I/O file operations, it can + * implement this optional callback. The exporter must verify that no + * other objects hold the sg_table, ensure exclusive access to the + * dmabuf's sg_table, and only then proceed with the I/O operation. + * + * Returns: + * + * 0 on success or a negative error code on failure. + */ + ssize_t (*rw_file)(struct dma_buf *dmabuf, loff_t my_pos, + struct file *file, loff_t pos, size_t count, bool is_write); }; /** -- 2.17.1