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-rw-r--r--net/dccp/ipv4.c32
1 files changed, 3 insertions, 29 deletions
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 6298cf58ff9e..4b9bc81ae1a3 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -31,8 +31,6 @@ struct inet_hashinfo __cacheline_aligned dccp_hashinfo = {
31 .lhash_lock = RW_LOCK_UNLOCKED, 31 .lhash_lock = RW_LOCK_UNLOCKED,
32 .lhash_users = ATOMIC_INIT(0), 32 .lhash_users = ATOMIC_INIT(0),
33 .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(dccp_hashinfo.lhash_wait), 33 .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(dccp_hashinfo.lhash_wait),
34 .portalloc_lock = SPIN_LOCK_UNLOCKED,
35 .port_rover = 1024 - 1,
36}; 34};
37 35
38EXPORT_SYMBOL_GPL(dccp_hashinfo); 36EXPORT_SYMBOL_GPL(dccp_hashinfo);
@@ -125,36 +123,15 @@ static int dccp_v4_hash_connect(struct sock *sk)
125 int ret; 123 int ret;
126 124
127 if (snum == 0) { 125 if (snum == 0) {
128 int rover;
129 int low = sysctl_local_port_range[0]; 126 int low = sysctl_local_port_range[0];
130 int high = sysctl_local_port_range[1]; 127 int high = sysctl_local_port_range[1];
131 int remaining = (high - low) + 1; 128 int remaining = (high - low) + 1;
129 int rover = net_random() % (high - low) + low;
132 struct hlist_node *node; 130 struct hlist_node *node;
133 struct inet_timewait_sock *tw = NULL; 131 struct inet_timewait_sock *tw = NULL;
134 132
135 local_bh_disable(); 133 local_bh_disable();
136
137 /* TODO. Actually it is not so bad idea to remove
138 * dccp_hashinfo.portalloc_lock before next submission to
139 * Linus.
140 * As soon as we touch this place at all it is time to think.
141 *
142 * Now it protects single _advisory_ variable
143 * dccp_hashinfo.port_rover, hence it is mostly useless.
144 * Code will work nicely if we just delete it, but
145 * I am afraid in contented case it will work not better or
146 * even worse: another cpu just will hit the same bucket
147 * and spin there.
148 * So some cpu salt could remove both contention and
149 * memory pingpong. Any ideas how to do this in a nice way?
150 */
151 spin_lock(&dccp_hashinfo.portalloc_lock);
152 rover = dccp_hashinfo.port_rover;
153
154 do { 134 do {
155 rover++;
156 if ((rover < low) || (rover > high))
157 rover = low;
158 head = &dccp_hashinfo.bhash[inet_bhashfn(rover, 135 head = &dccp_hashinfo.bhash[inet_bhashfn(rover,
159 dccp_hashinfo.bhash_size)]; 136 dccp_hashinfo.bhash_size)];
160 spin_lock(&head->lock); 137 spin_lock(&head->lock);
@@ -187,9 +164,9 @@ static int dccp_v4_hash_connect(struct sock *sk)
187 164
188 next_port: 165 next_port:
189 spin_unlock(&head->lock); 166 spin_unlock(&head->lock);
167 if (++rover > high)
168 rover = low;
190 } while (--remaining > 0); 169 } while (--remaining > 0);
191 dccp_hashinfo.port_rover = rover;
192 spin_unlock(&dccp_hashinfo.portalloc_lock);
193 170
194 local_bh_enable(); 171 local_bh_enable();
195 172
@@ -197,9 +174,6 @@ static int dccp_v4_hash_connect(struct sock *sk)
197 174
198ok: 175ok:
199 /* All locks still held and bhs disabled */ 176 /* All locks still held and bhs disabled */
200 dccp_hashinfo.port_rover = rover;
201 spin_unlock(&dccp_hashinfo.portalloc_lock);
202
203 inet_bind_hash(sk, tb, rover); 177 inet_bind_hash(sk, tb, rover);
204 if (sk_unhashed(sk)) { 178 if (sk_unhashed(sk)) {
205 inet_sk(sk)->sport = htons(rover); 179 inet_sk(sk)->sport = htons(rover);