mm/slub: move struct track init out of set_track()

set_track() either zeroes out the struct track or fills it, depending on
the addr parameter. This is unnecessary as there's only one place that
calls it for the initialization - init_tracking(). We can simply do the
zeroing there, with a single memset() that covers both TRACK_ALLOC and
TRACK_FREE as they are adjacent.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-and-tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>

diff --git a/mm/slub.c b/mm/slub.c
index 74d92aa..cd4fd01 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -729,34 +729,32 @@ static void set_track(struct kmem_cache *s, void *object,
 {
        struct track *p = get_track(s, object, alloc);
 
-       if (addr) {
 #ifdef CONFIG_STACKTRACE
-               unsigned int nr_entries;
+       unsigned int nr_entries;
 
-               metadata_access_enable();
-               nr_entries = stack_trace_save(kasan_reset_tag(p->addrs),
-                                             TRACK_ADDRS_COUNT, 3);
-               metadata_access_disable();
+       metadata_access_enable();
+       nr_entries = stack_trace_save(kasan_reset_tag(p->addrs),
+                                     TRACK_ADDRS_COUNT, 3);
+       metadata_access_disable();
 
-               if (nr_entries < TRACK_ADDRS_COUNT)
-                       p->addrs[nr_entries] = 0;
+       if (nr_entries < TRACK_ADDRS_COUNT)
+               p->addrs[nr_entries] = 0;
 #endif
-               p->addr = addr;
-               p->cpu = smp_processor_id();
-               p->pid = current->pid;
-               p->when = jiffies;
-       } else {
-               memset(p, 0, sizeof(struct track));
-       }
+       p->addr = addr;
+       p->cpu = smp_processor_id();
+       p->pid = current->pid;
+       p->when = jiffies;
 }
 
 static void init_tracking(struct kmem_cache *s, void *object)
 {
+       struct track *p;
+
        if (!(s->flags & SLAB_STORE_USER))
                return;
 
-       set_track(s, object, TRACK_FREE, 0UL);
-       set_track(s, object, TRACK_ALLOC, 0UL);
+       p = get_track(s, object, TRACK_ALLOC);
+       memset(p, 0, 2*sizeof(struct track));
 }
 
 static void print_track(const char *s, struct track *t, unsigned long pr_time)