RDMA/cma: Randomize local port allocation
Randomize local port allocation in the way sctp_get_port_local() does.
Update rover at the end of loop since we're likely to pick a valid port
on the first try.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 6d77706..6ae418e 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -79,7 +79,6 @@
static DEFINE_IDR(tcp_ps);
static DEFINE_IDR(udp_ps);
static DEFINE_IDR(ipoib_ps);
-static int next_port;
struct cma_device {
struct list_head list;
@@ -1970,47 +1969,33 @@
static int cma_alloc_any_port(struct idr *ps, struct rdma_id_private *id_priv)
{
- struct rdma_bind_list *bind_list;
- int port, ret, low, high;
-
- bind_list = kzalloc(sizeof *bind_list, GFP_KERNEL);
- if (!bind_list)
- return -ENOMEM;
-
-retry:
- /* FIXME: add proper port randomization per like inet_csk_get_port */
- do {
- ret = idr_get_new_above(ps, bind_list, next_port, &port);
- } while ((ret == -EAGAIN) && idr_pre_get(ps, GFP_KERNEL));
-
- if (ret)
- goto err1;
+ static unsigned int last_used_port;
+ int low, high, remaining;
+ unsigned int rover;
inet_get_local_port_range(&low, &high);
- if (port > high) {
- if (next_port != low) {
- idr_remove(ps, port);
- next_port = low;
- goto retry;
- }
- ret = -EADDRNOTAVAIL;
- goto err2;
+ remaining = (high - low) + 1;
+ rover = net_random() % remaining + low;
+retry:
+ if (last_used_port != rover &&
+ !idr_find(ps, (unsigned short) rover)) {
+ int ret = cma_alloc_port(ps, id_priv, rover);
+ /*
+ * Remember previously used port number in order to avoid
+ * re-using same port immediately after it is closed.
+ */
+ if (!ret)
+ last_used_port = rover;
+ if (ret != -EADDRNOTAVAIL)
+ return ret;
}
-
- if (port == high)
- next_port = low;
- else
- next_port = port + 1;
-
- bind_list->ps = ps;
- bind_list->port = (unsigned short) port;
- cma_bind_port(bind_list, id_priv);
- return 0;
-err2:
- idr_remove(ps, port);
-err1:
- kfree(bind_list);
- return ret;
+ if (--remaining) {
+ rover++;
+ if ((rover < low) || (rover > high))
+ rover = low;
+ goto retry;
+ }
+ return -EADDRNOTAVAIL;
}
static int cma_use_port(struct idr *ps, struct rdma_id_private *id_priv)
@@ -2995,12 +2980,7 @@
static int __init cma_init(void)
{
- int ret, low, high, remaining;
-
- get_random_bytes(&next_port, sizeof next_port);
- inet_get_local_port_range(&low, &high);
- remaining = (high - low) + 1;
- next_port = ((unsigned int) next_port % remaining) + low;
+ int ret;
cma_wq = create_singlethread_workqueue("rdma_cm");
if (!cma_wq)