block: introduce byte-based io helpers

Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

include/block/block_int.h

@@ -925,6 +925,22 @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
     int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
     BdrvRequestFlags flags);
 
+static inline int coroutine_fn bdrv_co_pread(BdrvChild *child,
+    int64_t offset, unsigned int bytes, void *buf, BdrvRequestFlags flags)
+{
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
+
+    return bdrv_co_preadv(child, offset, bytes, &qiov, flags);
+}
+
+static inline int coroutine_fn bdrv_co_pwrite(BdrvChild *child,
+    int64_t offset, unsigned int bytes, void *buf, BdrvRequestFlags flags)
+{
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
+
+    return bdrv_co_pwritev(child, offset, bytes, &qiov, flags);
+}
+
 extern unsigned int bdrv_drain_all_count;
 void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent);
 void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent);

include/sysemu/block-backend.h

@@ -124,6 +124,25 @@ int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
 int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset,
                                unsigned int bytes, QEMUIOVector *qiov,
                                BdrvRequestFlags flags);
+
+static inline int coroutine_fn blk_co_pread(BlockBackend *blk, int64_t offset,
+                                            unsigned int bytes, void *buf,
+                                            BdrvRequestFlags flags)
+{
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
+
+    return blk_co_preadv(blk, offset, bytes, &qiov, flags);
+}
+
+static inline int coroutine_fn blk_co_pwrite(BlockBackend *blk, int64_t offset,
+                                             unsigned int bytes, void *buf,
+                                             BdrvRequestFlags flags)
+{
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
+
+    return blk_co_pwritev(blk, offset, bytes, &qiov, flags);
+}
+
 int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset,
                       int bytes, BdrvRequestFlags flags);
 BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset,