@@ -155,7 +155,31 @@ BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset,
int bytes, BdrvRequestFlags flags,
BlockCompletionFunc *cb, void *opaque);
int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags);
+
+/**
+ * blk_pread:
+ *
+ * @blk: the block backend where the buffer content is going to be read from
+ * @offset: position in bytes to read at
+ * @buf: the data buffer
+ * @bytes: number of bytes to read
+ *
+ * Returns: the number of bytes read on success, or a negative errno otherwise.
+ */
int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int bytes);
+
+/**
+ * blk_pwrite:
+ *
+ * @blk: the block backend where the buffer content is going to be written to
+ * @offset: position in bytes to write at
+ * @buf: the data buffer
+ * @bytes: number of bytes of @buf to write
+ * @flags: request flags
+ *
+ * Returns: the number of bytes consumed on success,
+ * or a negative errno otherwise.
+ */
int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int bytes,
BdrvRequestFlags flags);
int64_t blk_getlength(BlockBackend *blk);
The blk_read()/blk_pwrite() return value is not obvious, document it. Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> --- v2: 's/ - /: /' (stefanha) --- include/sysemu/block-backend.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)