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| author | Johannes Berg <johannes.berg@intel.com> | 2015-04-23 17:38:43 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-04-24 18:38:12 +0300 |
| commit | 1d8dc3d3c8f1d8ee1da9d54c5d7c8694419ade42 (patch) | |
| tree | 8fee42496cb0eccbd5f48d406fa219aa017229b0 /include/linux/rhashtable.h | |
| parent | e580267df97eda407c525dbaee5430e0d51a0edb (diff) | |
| download | linux-1d8dc3d3c8f1d8ee1da9d54c5d7c8694419ade42.tar.xz | |
rhashtable: don't attempt to grow when at max_size
The conversion of mac80211's station table to rhashtable had a bug
that I found by accident in code review, that hadn't been found as
rhashtable apparently managed to have a maximum hash chain length
of one (!) in all our testing.
In order to test the bug and verify the fix I set my rhashtable's
max_size very low (4) in order to force getting hash collisions.
At that point, rhashtable WARNed in rhashtable_insert_rehash() but
didn't actually reject the hash table insertion. This caused it to
lose insertions - my master list of stations would have 9 entries,
but the rhashtable only had 5. This may warrant a deeper look, but
that WARN_ON() just shouldn't happen.
Fix this by not returning true from rht_grow_above_100() when the
rhashtable's max_size has been reached - in this case the user is
explicitly configuring it to be at most that big, so even if it's
now above 100% it shouldn't attempt to resize.
This fixes the "lost insertion" issue and consequently allows my
code to display its error (and verify my fix for it.)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/rhashtable.h')
| -rw-r--r-- | include/linux/rhashtable.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index e23d242d1230..dbcbcc59aa92 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -282,7 +282,8 @@ static inline bool rht_shrink_below_30(const struct rhashtable *ht, static inline bool rht_grow_above_100(const struct rhashtable *ht, const struct bucket_table *tbl) { - return atomic_read(&ht->nelems) > tbl->size; + return atomic_read(&ht->nelems) > tbl->size && + (!ht->p.max_size || tbl->size < ht->p.max_size); } /* The bucket lock is selected based on the hash and protects mutations |