Re: [Qemu-block] [Qemu-devel] [PATCH v4 12/20] qed: Switch to .bdrv_co_block_status()

[Eric Blake]

On 11/30/2017 04:27 AM, Vladimir Sementsov-Ogievskiy wrote:
> 12.10.2017 21:59, Eric Blake wrote:
> > We are gradually moving away from sector-based interfaces, towards
> > byte-based.  Update the qed driver accordingly, taking the opportunity
> > to inline qed_is_allocated_cb() into its lone caller (the callback
> > used to be important, until we switched qed to coroutines).  There is
> > no intent to optimize based on the want_zero flag for this format.
> >
> > Signed-off-by: Eric Blake <address@hidden>

> >   {
> >       BDRVQEDState *s = bs->opaque;
> > -    size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE;
> > -    QEDIsAllocatedCB cb = {
> > -        .bs = bs,
> > -        .pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE,
> > -        .status = BDRV_BLOCK_OFFSET_MASK,
> > -        .pnum = pnum,
> > -        .file = file,
> > -    };
> > +    size_t len;
>
> size_t len = bytes;

Or rather, size_t len = MIN(bytes, SIZE_MAX); thanks to 32-bit platforms.

> with that:
> Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>
>
> > +    int status;
> >       QEDRequest request = { .l2_table = NULL };
> >       uint64_t offset;
> >       int ret;
> >
> >       qemu_co_mutex_lock(&s->table_lock);
> > -    ret = qed_find_cluster(s, &request, cb.pos, &len, &offset);
> > -    qed_is_allocated_cb(&cb, ret, offset, len);
> > +    ret = qed_find_cluster(s, &request, pos, &len, &offset);
>
> len is in-out parameter, you can't use it uninitialized.

Good catch.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org