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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@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2015-10-02 11:43:23 -07:00 committed by David S. Miller
parent f6d3125fa3
commit fff1f3001c
3 changed files with 26 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
include/net/request_sock.h
View File

@ -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;
}

1
net/core/request_sock.c
View File

@ -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);

21
net/ipv4/inet_connection_sock.c
View File

@ -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);