[PATCH] lockdep: annotate sk_locks

Teach sk_lock semantics to the lock validator.  In the softirq path the
slock has mutex_trylock()+mutex_unlock() semantics, in the process context
sock_lock() case it has mutex_lock()/mutex_unlock() semantics.

Thus we treat sock_owned_by_user() flagged areas as an exclusion area too,
not just those areas covered by a held sk_lock.slock.

Effect on non-lockdep kernels: minimal, sk_lock_sock_init() has been turned
into an inline function.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 10 insertions, 10 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index 0969fb60d6ea..324b3ea233d6 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -44,6 +44,7 @@
 #include <linux/timer.h>
 #include <linux/cache.h>
 #include <linux/module.h>
+#include <linux/lockdep.h>
 #include <linux/netdevice.h>
 #include <linux/skbuff.h>       /* struct sk_buff */
 #include <linux/security.h>
@@ -78,18 +79,17 @@ typedef struct {
         spinlock_t              slock;
         struct sock_iocb        *owner;
         wait_queue_head_t       wq;
+        /*
+         * We express the mutex-alike socket_lock semantics
+         * to the lock validator by explicitly managing
+         * the slock as a lock variant (in addition to
+         * the slock itself):
+         */
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+        struct lockdep_map dep_map;
+#endif
 } socket_lock_t;
 
-extern struct lock_class_key af_family_keys[AF_MAX];
-
-#define sock_lock_init(__sk) \
-do {    spin_lock_init(&((__sk)->sk_lock.slock)); \
-        lockdep_set_class(&(__sk)->sk_lock.slock, \
-                          af_family_keys + (__sk)->sk_family); \
-        (__sk)->sk_lock.owner = NULL; \
-        init_waitqueue_head(&((__sk)->sk_lock.wq)); \
-} while(0)
-
 struct sock;
 struct proto;