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Commit 5d7220e8 authored by Tetsuo Handa's avatar Tetsuo Handa Committed by Roland Dreier
Browse files

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: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: default avatarSean Hefty <sean.hefty@intel.com>
Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent 0eddb519

drivers/infiniband/core/cma.c

+25 −45
Original line number Diff line number Diff line
@@ -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;

	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;

	}

		ret = -EADDRNOTAVAIL;

		goto err2;

	if (--remaining) {

		rover++;

		if ((rover < low) || (rover > high))

			rover = low;

		goto retry;

	}



	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;

	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)