block-backend: simplify blk_get_aio_context

blk_get_aio_context verifies if BlockDriverState bs is not NULL,
return bdrv_get_aio_context(bs) if true or qemu_get_aio_context()
otherwise. However, bdrv_get_aio_context from block.c already does
this verification itself, also returning qemu_get_aio_context()
if bs is NULL:

AioContext *bdrv_get_aio_context(BlockDriverState *bs)
{
    return bs ? bs->aio_context : qemu_get_aio_context();
}

This patch simplifies blk_get_aio_context to simply call
bdrv_get_aio_context instead of replicating the same logic.

Signed-off-by: Daniel Henrique Barboza <[email protected]>
Reviewed-by: Darren Kenny <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>

Author: danielhb

block/block-backend.c

@@ -1865,13 +1865,7 @@ void blk_op_unblock_all(BlockBackend *blk, Error *reason)
 
 AioContext *blk_get_aio_context(BlockBackend *blk)
 {
-    BlockDriverState *bs = blk_bs(blk);
-
-    if (bs) {
-        return bdrv_get_aio_context(bs);
-    } else {
-        return qemu_get_aio_context();
-    }
+    return bdrv_get_aio_context(blk_bs(blk));
 }
 
 static AioContext *blk_aiocb_get_aio_context(BlockAIOCB *acb)