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Message-Id: <1443811419-4798-2-git-send-email-edumazet@google.com>
Date: Fri, 2 Oct 2015 11:43:23 -0700
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>
Cc: netdev <netdev@...r.kernel.org>,
Eric Dumazet <edumazet@...gle.com>, Ying Cai <ycai@...gle.com>,
Willem de Bruijn <willemb@...gle.com>,
Eric Dumazet <eric.dumazet@...il.com>
Subject: [PATCH net-next 01/17] tcp: add a spinlock to protect struct request_sock_queue
struct request_sock_queue fields are currently protected
by the listener 'lock' (not a real spinlock)
We need to add a private spinlock instead, so that softirq handlers
creating children do not have to worry with backlog notion
that the listener 'lock' carries.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
include/net/request_sock.h | 37 ++++++++++++++++++-------------------
net/core/request_sock.c | 1 +
net/ipv4/inet_connection_sock.c | 21 +++++++--------------
3 files changed, 26 insertions(+), 33 deletions(-)
diff --git a/include/net/request_sock.h b/include/net/request_sock.h
index d2544de329bd..202e36163ae3 100644
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -176,9 +176,11 @@ struct fastopen_queue {
*
*/
struct request_sock_queue {
+ spinlock_t rskq_lock;
+ u8 rskq_defer_accept;
+
struct request_sock *rskq_accept_head;
struct request_sock *rskq_accept_tail;
- u8 rskq_defer_accept;
struct listen_sock *listen_opt;
struct fastopen_queue fastopenq; /* Check max_qlen != 0 to determine
* if TFO is enabled.
@@ -196,16 +198,7 @@ void reqsk_queue_destroy(struct request_sock_queue *queue);
void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req,
bool reset);
-static inline struct request_sock *
- reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
-{
- struct request_sock *req = queue->rskq_accept_head;
-
- queue->rskq_accept_head = NULL;
- return req;
-}
-
-static inline int reqsk_queue_empty(struct request_sock_queue *queue)
+static inline bool reqsk_queue_empty(const struct request_sock_queue *queue)
{
return queue->rskq_accept_head == NULL;
}
@@ -215,6 +208,7 @@ static inline void reqsk_queue_add(struct request_sock_queue *queue,
struct sock *parent,
struct sock *child)
{
+ spin_lock(&queue->rskq_lock);
req->sk = child;
sk_acceptq_added(parent);
@@ -225,18 +219,23 @@ static inline void reqsk_queue_add(struct request_sock_queue *queue,
queue->rskq_accept_tail = req;
req->dl_next = NULL;
+ spin_unlock(&queue->rskq_lock);
}
-static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
+static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue,
+ struct sock *parent)
{
- struct request_sock *req = queue->rskq_accept_head;
-
- WARN_ON(req == NULL);
-
- queue->rskq_accept_head = req->dl_next;
- if (queue->rskq_accept_head == NULL)
- queue->rskq_accept_tail = NULL;
+ struct request_sock *req;
+ spin_lock_bh(&queue->rskq_lock);
+ req = queue->rskq_accept_head;
+ if (req) {
+ sk_acceptq_removed(parent);
+ queue->rskq_accept_head = req->dl_next;
+ if (queue->rskq_accept_head == NULL)
+ queue->rskq_accept_tail = NULL;
+ }
+ spin_unlock_bh(&queue->rskq_lock);
return req;
}
diff --git a/net/core/request_sock.c b/net/core/request_sock.c
index e22cfa4ed25f..8d9fd31d3d06 100644
--- a/net/core/request_sock.c
+++ b/net/core/request_sock.c
@@ -58,6 +58,7 @@ int reqsk_queue_alloc(struct request_sock_queue *queue,
return -ENOMEM;
get_random_bytes(&lopt->hash_rnd, sizeof(lopt->hash_rnd));
+ spin_lock_init(&queue->rskq_lock);
spin_lock_init(&queue->syn_wait_lock);
spin_lock_init(&queue->fastopenq.lock);
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index e1527882a578..0085612b9e49 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -330,10 +330,9 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
if (error)
goto out_err;
}
- req = reqsk_queue_remove(queue);
+ req = reqsk_queue_remove(queue, sk);
newsk = req->sk;
- sk_acceptq_removed(sk);
if (sk->sk_protocol == IPPROTO_TCP &&
tcp_rsk(req)->tfo_listener) {
spin_lock_bh(&queue->fastopenq.lock);
@@ -832,11 +831,7 @@ void inet_csk_listen_stop(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct request_sock_queue *queue = &icsk->icsk_accept_queue;
- struct request_sock *acc_req;
- struct request_sock *req;
-
- /* make all the listen_opt local to us */
- acc_req = reqsk_queue_yank_acceptq(queue);
+ struct request_sock *next, *req;
/* Following specs, it would be better either to send FIN
* (and enter FIN-WAIT-1, it is normal close)
@@ -848,11 +843,9 @@ void inet_csk_listen_stop(struct sock *sk)
*/
reqsk_queue_destroy(queue);
- while ((req = acc_req) != NULL) {
+ while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
struct sock *child = req->sk;
- acc_req = req->dl_next;
-
local_bh_disable();
bh_lock_sock(child);
WARN_ON(sock_owned_by_user(child));
@@ -882,18 +875,18 @@ void inet_csk_listen_stop(struct sock *sk)
local_bh_enable();
sock_put(child);
- sk_acceptq_removed(sk);
reqsk_put(req);
}
if (queue->fastopenq.rskq_rst_head) {
/* Free all the reqs queued in rskq_rst_head. */
spin_lock_bh(&queue->fastopenq.lock);
- acc_req = queue->fastopenq.rskq_rst_head;
+ req = queue->fastopenq.rskq_rst_head;
queue->fastopenq.rskq_rst_head = NULL;
spin_unlock_bh(&queue->fastopenq.lock);
- while ((req = acc_req) != NULL) {
- acc_req = req->dl_next;
+ while (req != NULL) {
+ next = req->dl_next;
reqsk_put(req);
+ req = next;
}
}
WARN_ON(sk->sk_ack_backlog);
--
2.6.0.rc2.230.g3dd15c0
--
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