[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Ping: [PATCH 11/11] gnttab: drop useless locking
>>> On 21.06.17 at 11:38, <JBeulich@xxxxxxxx> wrote: > Holding any lock while accessing the maptrack entry fields is > pointless, as these entries are protected by their associated active > entry lock (which is being acquired later, before re-validating the > fields read without holding the lock). > > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> > > --- a/xen/common/grant_table.c > +++ b/xen/common/grant_table.c > @@ -1122,19 +1122,14 @@ __gnttab_unmap_common( > smp_rmb(); > map = &maptrack_entry(lgt, op->handle); > > - grant_read_lock(lgt); > - > if ( unlikely(!read_atomic(&map->flags)) ) > { > - grant_read_unlock(lgt); > gdprintk(XENLOG_INFO, "Zero flags for handle %#x\n", op->handle); > op->status = GNTST_bad_handle; > return; > } > > dom = map->domid; > - grant_read_unlock(lgt); > - > if ( unlikely((rd = rcu_lock_domain_by_id(dom)) == NULL) ) > { > /* This can happen when a grant is implicitly unmapped. */ _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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