From 5d7220e8dc24feed4bbd66667b7696906a147ac4 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Thu, 15 Apr 2010 11:29:04 +0900 Subject: 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 Reviewed-by: Sean Hefty Signed-off-by: Roland Dreier --- drivers/infiniband/core/cma.c | 70 ++++++++++++++++--------------------------- 1 file changed, 25 insertions(+), 45 deletions(-) (limited to 'drivers/infiniband/core') diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c index 6d777069d86d..6ae418e81d82 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -79,7 +79,6 @@ static DEFINE_IDR(sdp_ps); 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 @@ err1: 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 void cma_remove_one(struct ib_device *device) 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) -- cgit v1.2.3