Re: [libvirt] [PATCH v2 2/3] util: Clear unused part of the map in virBitmapShrink

On Fri, Feb 02, 2018 at 14:04:31 +0100, Martin Kletzander wrote: > Some of the other functions depend on the fact that unused bits and longs are > always zero and it's less error-prone to clear it than fix the other functions. > It's enough to zero out one piece of the map since we're calling realloc() to > get rid of the rest (and updating map_len). > > Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1540817 > > Signed-off-by: Martin Kletzander <mkletzan(a)redhat.com&gt; > --- > src/conf/domain_conf.c | 4 +++- > src/util/virbitmap.c | 30 ++++++++++++++++++++++-------- > src/util/virbitmap.h | 2 +- > src/util/virresctrl.c | 3 ++- > tests/virbitmaptest.c | 8 ++++++++ > 5 files changed, 36 insertions(+), 11 deletions(-) > > diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c > index 01d168eb875b..e827b2a810f7 100644 > --- a/src/conf/domain_conf.c > +++ b/src/conf/domain_conf.c > @@ -18453,7 +18453,9 @@ virDomainCachetuneDefParse(virDomainDefPtr def, > > /* We need to limit the bitmap to number of vCPUs. If there's nothing left, > * then we can just clean up and return 0 immediately */ > - virBitmapShrink(vcpus, def->maxvcpus); > + if (virBitmapShrink(vcpus, def->maxvcpus) < 0) > + goto cleanup; > + > if (virBitmapIsAllClear(vcpus)) { > ret = 0; > goto cleanup; > diff --git a/src/util/virbitmap.c b/src/util/virbitmap.c > index b2c5c7a6a5ac..33cae2f30569 100644 > --- a/src/util/virbitmap.c > +++ b/src/util/virbitmap.c > @@ -1201,21 +1201,35 @@ virBitmapSubtract(virBitmapPtr a, > /** > * virBitmapShrink: > * @map: Pointer to bitmap > - * @b: last bit position to be excluded from bitmap > + * @b: Size to reduce the bitmap to > * > - * Resizes the bitmap so that no more than @b bits will fit into it. Nothing > - * will change if the size is already smaller than @b. > - * > - * NB: Does not adjust the map->map_len so that a subsequent virBitmapExpand > - * doesn't necessarily need to reallocate. > + * Reduces the bitmap to size @b. Nothing will change if the size is already > + * smaller than or equal to @b. > */ > -void > +int > virBitmapShrink(virBitmapPtr map, > size_t b) > { > + size_t nl = 0; > + size_t nb = 0; > + > if (!map) > - return; > + return 0; > > if (map->max_bit >= b) > map->max_bit = b; > + > + nl = map->max_bit / VIR_BITMAP_BITS_PER_UNIT; > + nb = map->max_bit % VIR_BITMAP_BITS_PER_UNIT; > + map->map[nl] &= ((1UL << nb) - 1); > + > + nl++; > + if (nl == map->map_len) > + return 0; > + > + if (VIR_REALLOC_N(map->map, nl) < 0) With VIR_SHRINK_N you can avoid the return value ;)

ACK

-- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list