On Thu, Oct 10, 2024 at 06:48:26PM -0700, Andrii Nakryiko wrote:
> On Wed, Oct 9, 2024 at 1:20 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
> >
> > The hashmap__for_each_entry[_safe] is accessing 'map' as if it's a
> > pointer. But it does without parentheses so passing a static hash map
> > with an ampersand (like &slab_hash below) caused compiler warnings due
> > to unmatched types.
> >
> > In file included from util/bpf_lock_contention.c:5:
> > util/bpf_lock_contention.c: In function ‘exit_slab_cache_iter’:
> > linux/tools/perf/util/hashmap.h:169:32: error: invalid type argument of ‘->’ (have ‘struct hashmap’)
> > 169 | for (bkt = 0; bkt < map->cap; bkt++) \
> > | ^~
> > util/bpf_lock_contention.c:105:9: note: in expansion of macro ‘hashmap__for_each_entry’
> > 105 | hashmap__for_each_entry(&slab_hash, cur, bkt)
> > | ^~~~~~~~~~~~~~~~~~~~~~~
> > /home/namhyung/project/linux/tools/perf/util/hashmap.h:170:31: error: invalid type argument of ‘->’ (have ‘struct hashmap’)
> > 170 | for (cur = map->buckets[bkt]; cur; cur = cur->next)
> > | ^~
> > util/bpf_lock_contention.c:105:9: note: in expansion of macro ‘hashmap__for_each_entry’
> > 105 | hashmap__for_each_entry(&slab_hash, cur, bkt)
> > | ^~~~~~~~~~~~~~~~~~~~~~~
> >
> > Cc: bpf@xxxxxxxxxxxxxxx
> > Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> > ---
> > I've discovered this while prototyping the slab symbolization for perf
> > lock contention. So this code is not available yet but I'd like to fix
> > the problem first.
> >
> > Also noticed bpf has the same code and the same problem. I'll send a
> > separate patch for them.
> >
>
> Yep, please do. Fixes look good, thanks.
Sure will do, can I get your Acked-by for this patch?
Thanks,
Namhyung
>
> > tools/perf/util/hashmap.h | 20 ++++++++++----------
> > 1 file changed, 10 insertions(+), 10 deletions(-)
> >
> > diff --git a/tools/perf/util/hashmap.h b/tools/perf/util/hashmap.h
> > index c12f8320e6682d50..0c4f155e8eb745d9 100644
> > --- a/tools/perf/util/hashmap.h
> > +++ b/tools/perf/util/hashmap.h
> > @@ -166,8 +166,8 @@ bool hashmap_find(const struct hashmap *map, long key, long *value);
> > * @bkt: integer used as a bucket loop cursor
> > */
> > #define hashmap__for_each_entry(map, cur, bkt) \
> > - for (bkt = 0; bkt < map->cap; bkt++) \
> > - for (cur = map->buckets[bkt]; cur; cur = cur->next)
> > + for (bkt = 0; bkt < (map)->cap; bkt++) \
> > + for (cur = (map)->buckets[bkt]; cur; cur = cur->next)
> >
> > /*
> > * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
> > @@ -178,8 +178,8 @@ bool hashmap_find(const struct hashmap *map, long key, long *value);
> > * @bkt: integer used as a bucket loop cursor
> > */
> > #define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \
> > - for (bkt = 0; bkt < map->cap; bkt++) \
> > - for (cur = map->buckets[bkt]; \
> > + for (bkt = 0; bkt < (map)->cap; bkt++) \
> > + for (cur = (map)->buckets[bkt]; \
> > cur && ({tmp = cur->next; true; }); \
> > cur = tmp)
> >
> > @@ -190,19 +190,19 @@ bool hashmap_find(const struct hashmap *map, long key, long *value);
> > * @key: key to iterate entries for
> > */
> > #define hashmap__for_each_key_entry(map, cur, _key) \
> > - for (cur = map->buckets \
> > - ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
> > + for (cur = (map)->buckets \
> > + ? (map)->buckets[hash_bits((map)->hash_fn((_key), (map)->ctx), (map)->cap_bits)] \
> > : NULL; \
> > cur; \
> > cur = cur->next) \
> > - if (map->equal_fn(cur->key, (_key), map->ctx))
> > + if ((map)->equal_fn(cur->key, (_key), (map)->ctx))
> >
> > #define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \
> > - for (cur = map->buckets \
> > - ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
> > + for (cur = (map)->buckets \
> > + ? (map)->buckets[hash_bits((map)->hash_fn((_key), (map)->ctx), (map)->cap_bits)] \
> > : NULL; \
> > cur && ({ tmp = cur->next; true; }); \
> > cur = tmp) \
> > - if (map->equal_fn(cur->key, (_key), map->ctx))
> > + if ((map)->equal_fn(cur->key, (_key), (map)->ctx))
> >
> > #endif /* __LIBBPF_HASHMAP_H */
> > --
> > 2.47.0.rc0.187.ge670bccf7e-goog
> >
> >
