net: sched: fix call_rcu() race on classifier module unloads

[karo-tx-linux.git] / lib / rhashtable.c

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 4898442b837fbd715f8d5079a1060e43c4b7a367..4396434e471536b4772ef06efcb983f87c580889 100644 (file)
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -14,6 +14,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/atomic.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/log2.h>
@@ -405,13 +406,18 @@ int rhashtable_insert_rehash(struct rhashtable *ht)
 
        if (rht_grow_above_75(ht, tbl))
                size *= 2;
-       /* More than two rehashes (not resizes) detected. */
-       else if (WARN_ON(old_tbl != tbl && old_tbl->size == size))
+       /* Do not schedule more than one rehash */
+       else if (old_tbl != tbl)
                return -EBUSY;
 
        new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC);
-       if (new_tbl == NULL)
+       if (new_tbl == NULL) {
+               /* Schedule async resize/rehash to try allocation
+                * non-atomic context.
+                */
+               schedule_work(&ht->run_work);
                return -ENOMEM;
+       }
 
        err = rhashtable_rehash_attach(ht, tbl, new_tbl);
        if (err) {
@@ -441,6 +447,10 @@ int rhashtable_insert_slow(struct rhashtable *ht, const void *key,
        if (key && rhashtable_lookup_fast(ht, key, ht->p))
                goto exit;
 
+       err = -E2BIG;
+       if (unlikely(rht_grow_above_max(ht, tbl)))
+               goto exit;
+
        err = -EAGAIN;
        if (rhashtable_check_elasticity(ht, tbl, hash) ||
            rht_grow_above_100(ht, tbl))
@@ -733,6 +743,12 @@ int rhashtable_init(struct rhashtable *ht,
        if (params->max_size)
                ht->p.max_size = rounddown_pow_of_two(params->max_size);
 
+       if (params->insecure_max_entries)
+               ht->p.insecure_max_entries =
+                       rounddown_pow_of_two(params->insecure_max_entries);
+       else
+               ht->p.insecure_max_entries = ht->p.max_size * 2;
+
        ht->p.min_size = max(ht->p.min_size, HASH_MIN_SIZE);
 
        /* The maximum (not average) chain length grows with the