[RFC (fix for 5.0?)] block/io: do not do pointer arithmetic on void *

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---

Hi all!

C standard doesn't allow pointer arithmetic on void *.
Still, gcc allows it as an extension:
 https://gcc.gnu.org/onlinedocs/gcc-4.8.0/gcc/Pointer-Arith.html

I can create a series of patches like this. Do we need it?

Also, where is documented which compilers are supported by Qemu?

 block/io.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/io.c b/block/io.c
index aba67f66b9..539178aed5 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1277,7 +1277,7 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
      * modifying the image file.  This is critical for zero-copy guest I/O
      * where anything might happen inside guest memory.
      */
-    void *bounce_buffer = NULL;
+    char *bounce_buffer = NULL;
 
     BlockDriver *drv = bs->drv;
     int64_t cluster_offset;
-- 
2.21.0