First determine if dmabuf reads from or writes to the file.
Then call exporter's rw_file callback function.
Signed-off-by: wangtao <tao.wang...@honor.com>
---
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 <linux/fs.h>
#include <linux/dma-fence.h>
#include <linux/wait.h>
+#include <uapi/linux/dma-buf.h>
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
