Re: [PATCH v2 06/22] block/mirror: fix -Werror=maybe-uninitialized false-positive

[Manos Pitsidianakis]

On Tue, 24 Sep 2024 16:05, marcandre.lureau@redhat.com wrote:
> From: Marc-André Lureau <marcandre.lureau@redhat.com>
>
> ../block/mirror.c:404:5: error: ‘ret’ may be used uninitialized 
> [-Werror=maybe-uninitialized]
> ../block/mirror.c:895:12: error: ‘ret’ may be used uninitialized 
> [-Werror=maybe-uninitialized]
> ../block/mirror.c:578:12: error: ‘ret’ may be used uninitialized 
> [-Werror=maybe-uninitialized]
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
> block/mirror.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/block/mirror.c b/block/mirror.c
> index 54e3a7ea9d..fd55a580fb 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -349,7 +349,7 @@ static void coroutine_fn mirror_co_read(void *opaque)
>     MirrorOp *op = opaque;
>     MirrorBlockJob *s = op->s;
>     int nb_chunks;
> -    uint64_t ret;
> +    uint64_t ret = -1;

This doesn't look right, `ret` should be int. It receives the return 
result of bdrv_co_preadv() which is int and is passed as an int argument 
to mirror_read_complete().

Not related to this patch obviously. But since you're touching this code 
maybe we could include this small cleanup?


>     uint64_t max_bytes;
>
>     max_bytes = s->granularity * s->max_iov;
> @@ -565,7 +565,7 @@ static void coroutine_fn GRAPH_UNLOCKED 
> mirror_iteration(MirrorBlockJob *s)
>
>     bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks);
>     while (nb_chunks > 0 && offset < s->bdev_length) {
> -        int ret;
> +        int ret = -1;
>         int64_t io_bytes;
>         int64_t io_bytes_acct;
>         MirrorMethod mirror_method = MIRROR_METHOD_COPY;
> @@ -841,7 +841,7 @@ static int coroutine_fn GRAPH_UNLOCKED 
> mirror_dirty_init(MirrorBlockJob *s)
>     int64_t offset;
>     BlockDriverState *bs;
>     BlockDriverState *target_bs = blk_bs(s->target);
> -    int ret;
> +    int ret = -1;
>     int64_t count;
>
>     bdrv_graph_co_rdlock();
> --
> 2.45.2.827.g557ae147e6