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authorEric Dumazet <eric.dumazet@gmail.com>2009-12-08 20:19:53 -0800
committerDavid S. Miller <davem@davemloft.net>2009-12-08 20:19:53 -0800
commit2a8875e73ffb18165ceb245f99c2ccad77378051 (patch)
treef2a443bef4aec863b9b4143e528357518db0b89c
parenttcp: Fix a connect() race with timewait sockets (diff)
downloadlinux-dev-2a8875e73ffb18165ceb245f99c2ccad77378051.tar.xz
linux-dev-2a8875e73ffb18165ceb245f99c2ccad77378051.zip
[PATCH] tcp: documents timewait refcnt tricks
Adds kerneldoc for inet_twsk_unhash() & inet_twsk_bind_unhash(). With help from Randy Dunlap. Suggested-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/inet_timewait_sock.c38
1 files changed, 24 insertions, 14 deletions
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index bf4b1e2a4305..cc94cc2d8b2d 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -15,9 +15,13 @@
#include <net/ip.h>
-/*
- * unhash a timewait socket from established hash
- * lock must be hold by caller
+/**
+ * inet_twsk_unhash - unhash a timewait socket from established hash
+ * @tw: timewait socket
+ *
+ * unhash a timewait socket from established hash, if hashed.
+ * ehash lock must be held by caller.
+ * Returns 1 if caller should call inet_twsk_put() after lock release.
*/
int inet_twsk_unhash(struct inet_timewait_sock *tw)
{
@@ -26,12 +30,21 @@ int inet_twsk_unhash(struct inet_timewait_sock *tw)
hlist_nulls_del_rcu(&tw->tw_node);
sk_nulls_node_init(&tw->tw_node);
+ /*
+ * We cannot call inet_twsk_put() ourself under lock,
+ * caller must call it for us.
+ */
return 1;
}
-/*
- * unhash a timewait socket from bind hash
- * lock must be hold by caller
+/**
+ * inet_twsk_bind_unhash - unhash a timewait socket from bind hash
+ * @tw: timewait socket
+ * @hashinfo: hashinfo pointer
+ *
+ * unhash a timewait socket from bind hash, if hashed.
+ * bind hash lock must be held by caller.
+ * Returns 1 if caller should call inet_twsk_put() after lock release.
*/
int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
struct inet_hashinfo *hashinfo)
@@ -44,6 +57,10 @@ int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
__hlist_del(&tw->tw_bind_node);
tw->tw_tb = NULL;
inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
+ /*
+ * We cannot call inet_twsk_put() ourself under lock,
+ * caller must call it for us.
+ */
return 1;
}
@@ -139,7 +156,7 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
/*
* Notes :
- * - We initially set tw_refcnt to 0 in inet_twsk_alloc()
+ * - We initially set tw_refcnt to 0 in inet_twsk_alloc()
* - We add one reference for the bhash link
* - We add one reference for the ehash link
* - We want this refcnt update done before allowing other
@@ -149,7 +166,6 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
spin_unlock(lock);
}
-
EXPORT_SYMBOL_GPL(__inet_twsk_hashdance);
struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk, const int state)
@@ -190,7 +206,6 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk, const int stat
return tw;
}
-
EXPORT_SYMBOL_GPL(inet_twsk_alloc);
/* Returns non-zero if quota exceeded. */
@@ -269,7 +284,6 @@ void inet_twdr_hangman(unsigned long data)
out:
spin_unlock(&twdr->death_lock);
}
-
EXPORT_SYMBOL_GPL(inet_twdr_hangman);
void inet_twdr_twkill_work(struct work_struct *work)
@@ -300,7 +314,6 @@ void inet_twdr_twkill_work(struct work_struct *work)
spin_unlock_bh(&twdr->death_lock);
}
}
-
EXPORT_SYMBOL_GPL(inet_twdr_twkill_work);
/* These are always called from BH context. See callers in
@@ -320,7 +333,6 @@ void inet_twsk_deschedule(struct inet_timewait_sock *tw,
spin_unlock(&twdr->death_lock);
__inet_twsk_kill(tw, twdr->hashinfo);
}
-
EXPORT_SYMBOL(inet_twsk_deschedule);
void inet_twsk_schedule(struct inet_timewait_sock *tw,
@@ -401,7 +413,6 @@ void inet_twsk_schedule(struct inet_timewait_sock *tw,
mod_timer(&twdr->tw_timer, jiffies + twdr->period);
spin_unlock(&twdr->death_lock);
}
-
EXPORT_SYMBOL_GPL(inet_twsk_schedule);
void inet_twdr_twcal_tick(unsigned long data)
@@ -462,7 +473,6 @@ out:
#endif
spin_unlock(&twdr->death_lock);
}
-
EXPORT_SYMBOL_GPL(inet_twdr_twcal_tick);
void inet_twsk_purge(struct inet_hashinfo *hashinfo,