Re: [Qemu-block] [Qemu-devel] [PATCH] nvme: Make nvme_init error handling code more readable

[Peter Maydell]

On 21 May 2018 at 07:35, Fam Zheng <address@hidden> wrote:
> Coverity doesn't like the tests under fail label (report CID 1385847).
> Reset the fields so the clean up order is more apparent.
>
> Signed-off-by: Fam Zheng <address@hidden>
> ---
>  block/nvme.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/block/nvme.c b/block/nvme.c
> index 6f71122bf5..8239b920c8 100644
> --- a/block/nvme.c
> +++ b/block/nvme.c
> @@ -560,6 +560,13 @@ static int nvme_init(BlockDriverState *bs, const char 
> *device, int namespace,
>      qemu_co_queue_init(&s->dma_flush_queue);
>      s->nsid = namespace;
>      s->aio_context = bdrv_get_aio_context(bs);
> +
> +    /* Fields we've not touched should be zero-initialized by block layer
> +     * already, but reset them anyway to make the error handling code easier 
> to
> +     * reason. */
> +    s->regs = NULL;
> +    s->vfio = NULL;
> +
>      ret = event_notifier_init(&s->irq_notifier, 0);
>      if (ret) {
>          error_setg(errp, "Failed to init event notifier");

I suspect that either coverity or some compilers will complain that
the assignment to s->vfio here is redundant, because we'll either
return early without looking at it, or we'll get to the assignment
 s->vfio = qemu_vfio_open_pci(...)
which overrides it.

thanks
-- PMM