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* netfilter: nf_conntrack: nf_conntrack_alloc() fixesEric Dumazet2009-07-161-1/+6
| | | | | | | | | | | | | | | | | | | | | | When a slab cache uses SLAB_DESTROY_BY_RCU, we must be careful when allocating objects, since slab allocator could give a freed object still used by lockless readers. In particular, nf_conntrack RCU lookups rely on ct->tuplehash[xxx].hnnode.next being always valid (ie containing a valid 'nulls' value, or a valid pointer to next object in hash chain.) kmem_cache_zalloc() setups object with NULL values, but a NULL value is not valid for ct->tuplehash[xxx].hnnode.next. Fix is to call kmem_cache_alloc() and do the zeroing ourself. As spotted by Patrick, we also need to make sure lookup keys are committed to memory before setting refcount to 1, or a lockless reader could get a reference on the old version of the object. Its key re-check could then pass the barrier. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Patrick McHardy <kaber@trash.net>
* trivial: Miscellaneous documentation typo fixesMatt LaPlante2009-06-121-1/+1
| | | | | | | Fix various typos in documentation txts. Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* Doc: Fix spelling in RCU/rculist_nulls.txt.Jesper Dangaard Brouer2009-04-021-2/+2
| | | | | | | | | | | | Doc: Fix spelling in RCU/rculist_nulls.txt. Trival spelling fixes in RCU/rculist_nulls.txt. Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk> Tested-by: Jarek Poplawski <jarkao2@gmail.com;-> Signed-off-by: David S. Miller <davem@davemloft.net>
* rcu: documents rculist_nullsEric Dumazet2008-11-161-0/+167
Adds Documentation/RCU/rculist_nulls.txt file to describe how 'nulls' end-of-list can help in some RCU algos. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: David S. Miller <davem@davemloft.net>
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