On Tue, Aug 18, 2026 at 11:15 PM Alexander Graf <[email protected]> wrote: > > The comment above VIRTIO_DEVICE_F_MASK spells the mask out by hand as > 0xfffffc000fffffff, which was correct while VIRTIO_TRANSPORT_F_END was > 41. The bound is 42 now, so the macro expands to 0xfffff8000fffffff and > whoever reads the comment to check a feature mask against it gets the > wrong boundary between transport and per-device bits. > > Correcting the number would leave a comment that has to be updated by > hand every time the bound moves, and we already missed it once. Drop the > expansion instead. The macro derives its value from the bound and needs > no change. > > Fixes: 838bebb4c926 ("virtio: Define feature bit for administration > virtqueue") > Suggested-by: Michael S. Tsirkin <[email protected]>
Acked-by: Eugenio Pérez <[email protected]> I'm not sure if a Fixes is needed though, as it will cause backports (which means work) that don't fix any code. > Assisted-by: Kiro:claude-opus-5 checkpatch sparse > Signed-off-by: Alexander Graf <[email protected]> > --- > drivers/vdpa/vdpa.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c > index 47c6c3d23f5c..395ca549573a 100644 > --- a/drivers/vdpa/vdpa.c > +++ b/drivers/vdpa/vdpa.c > @@ -548,10 +548,9 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff *msg, > struct netlink_callback *cb) > > /* > * Bitmask for all per-device features: feature bits VIRTIO_TRANSPORT_F_START > - * through VIRTIO_TRANSPORT_F_END are unset, i.e. 0xfffffc000fffffff for > - * all 64bit features. If the features are extended beyond 64 bits, or new > - * "holes" are reserved for other type of features than per-device, this > - * macro would have to be updated. > + * through VIRTIO_TRANSPORT_F_END are unset. If the features are extended > + * beyond 64 bits, or new "holes" are reserved for other type of features > + * than per-device, this macro would have to be updated. > */ > #define VIRTIO_DEVICE_F_MASK (~0ULL << (VIRTIO_TRANSPORT_F_END + 1) | \ > ((1ULL << VIRTIO_TRANSPORT_F_START) - 1)) >
