block: drop bdrv_prwv

Now that we are not maintaining boilerplate code for coroutine
wrappers, there is no more sense in keeping the extra indirection layer
of bdrv_prwv().  Let's drop it and instead generate pure bdrv_preadv()
and bdrv_pwritev().

Currently, bdrv_pwritev() and bdrv_preadv() are returning bytes on
success, auto generated functions will instead return zero, as their
_co_ prototype. Still, it's simple to make the conversion safe: the
only external user of bdrv_pwritev() is test-bdrv-drain, and it is
comfortable enough with bdrv_co_pwritev() instead. So prototypes are
moved to local block/coroutines.h. Next, the only internal use is
bdrv_pread() and bdrv_pwrite(), which are modified to return bytes on
success.

Of course, it would be great to convert bdrv_pread() and bdrv_pwrite()
to return 0 on success. But this requires audit (and probably
conversion) of all their users, let's leave it for another day
refactoring.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200924185414.28642-7-vsementsov@virtuozzo.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index 1107271840..1595bbc92e 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -1872,7 +1872,7 @@ static int coroutine_fn bdrv_replace_test_co_preadv(BlockDriverState *bs,
         }
         s->io_co = NULL;
 
-        ret = bdrv_preadv(bs->backing, offset, qiov);
+        ret = bdrv_co_preadv(bs->backing, offset, bytes, qiov, 0);
         s->has_read = true;
 
         /* Wake up drain_co if it runs */