Eric Lee / smarc-fsl-linux-kernel

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Commit 75c5a2e788ab02f67931442e8dcbc854ae7252d1

Authored by Matthias Schiffer
Committed by Antonio Quartulli
1 parent ef3a409391

batman-adv: fix locking in hash_add() 

To ensure an entry isn't added twice all comparisons have to be protected by the
hash line write spinlock. This doesn't really hurt as the case that it is tried
to add an element already present to the hash shouldn't occur very often, so in
most cases the lock would have have to be taken anyways.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Acked-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Sven Eckelmann <sven@narfation.org>

Showing 1 changed file with 6 additions and 9 deletions Side-by-side Diff

net/batman-adv/hash.h
Diff comments   View file @ 75c5a2e
... ... @@ -110,26 +110,23 @@
110 110 head = &hash->table[index];
111 111 list_lock = &hash->list_locks[index];
112 112  
113   - rcu_read_lock();
114   - __hlist_for_each_rcu(node, head) {
  113 + spin_lock_bh(list_lock);
  114 +
  115 + hlist_for_each(node, head) {
115 116 if (!compare(node, data))
116 117 continue;
117 118  
118 119 ret = 1;
119   - goto err_unlock;
  120 + goto unlock;
120 121 }
121   - rcu_read_unlock();
122 122  
123 123 /* no duplicate found in list, add new element */
124   - spin_lock_bh(list_lock);
125 124 hlist_add_head_rcu(data_node, head);
126   - spin_unlock_bh(list_lock);
127 125  
128 126 ret = 0;
129   - goto out;
130 127  
131   -err_unlock:
132   - rcu_read_unlock();
  128 +unlock:
  129 + spin_unlock_bh(list_lock);
133 130 out:
134 131 return ret;
135 132 }