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authorLinus Torvalds <torvalds@linux-foundation.org>2009-07-22 09:49:58 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-07-22 09:49:58 -0700
commit402168cee1a0b791c54c54a68ae21bb26880f40b (patch)
tree127b1bd8f2d06b18449998022eaab1c20baab950 /Documentation/RCU/rculist_nulls.txt
parent12e8ffe35eaca1411afc1f3124478f8e2b65eedc (diff)
parenta947a39d52f5b647a2fd5eca55d39e722a2fa90f (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (37 commits) sky2: Avoid races in sky2_down drivers/net/mlx4: Adjust constant drivers/net: Move a dereference below a NULL test drivers/net: Move a dereference below a NULL test connector: maintainer/mail update. USB host CDC Phonet network interface driver macsonic, jazzsonic: fix oops on module unload macsonic: move probe function to .devinit.text can: switch carrier on if device was stopped while in bus-off state can: restart device even if dev_alloc_skb() fails can: sja1000: remove duplicated includes New device ID for sc92031 [1088:2031] 3c589_cs: re-initialize the multicast in the tc589_reset Fix error return for setsockopt(SO_TIMESTAMPING) netxen: fix thermal check and shutdown netxen: fix deadlock on dev close netxen: fix context deletion sequence net: Micrel KS8851 SPI network driver tcp: Use correct peer adr when copying MD5 keys tcp: Fix MD5 signature checking on IPv4 mapped sockets ...
Diffstat (limited to 'Documentation/RCU/rculist_nulls.txt')
-rw-r--r--Documentation/RCU/rculist_nulls.txt7
1 files changed, 6 insertions, 1 deletions
diff --git a/Documentation/RCU/rculist_nulls.txt b/Documentation/RCU/rculist_nulls.txt
index 93cb28d05dc..18f9651ff23 100644
--- a/Documentation/RCU/rculist_nulls.txt
+++ b/Documentation/RCU/rculist_nulls.txt
@@ -83,11 +83,12 @@ not detect it missed following items in original chain.
obj = kmem_cache_alloc(...);
lock_chain(); // typically a spin_lock()
obj->key = key;
-atomic_inc(&obj->refcnt);
/*
* we need to make sure obj->key is updated before obj->next
+ * or obj->refcnt
*/
smp_wmb();
+atomic_set(&obj->refcnt, 1);
hlist_add_head_rcu(&obj->obj_node, list);
unlock_chain(); // typically a spin_unlock()
@@ -159,6 +160,10 @@ out:
obj = kmem_cache_alloc(cachep);
lock_chain(); // typically a spin_lock()
obj->key = key;
+/*
+ * changes to obj->key must be visible before refcnt one
+ */
+smp_wmb();
atomic_set(&obj->refcnt, 1);
/*
* insert obj in RCU way (readers might be traversing chain)