Commit bcfa98a5 authored by NeilBrown's avatar NeilBrown Committed by Greg Kroah-Hartman
Browse files

staging: lustre: replace cfs_rand() with prandom_u32_max() 



All occurrences of
   cfs_rand() % X
are replaced with
   prandom_u32_max(X)

cfs_rand() is a simple Linear Congruential PRNG.  prandom_u32_max()
is at least as random, is seeded with more randomness, and uses
cpu-local state to avoid cross-cpu issues.

This is the first step is discarding the libcfs prng with
the standard linux prng.

Signed-off-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 19ae89d3

drivers/staging/lustre/lnet/libcfs/fail.c

+1 −1
Original line number Diff line number Diff line
@@ -61,7 +61,7 @@ int __cfs_fail_check_set(u32 id, u32 value, int set) 


	/* Fail 1/cfs_fail_val times */

	if (cfs_fail_loc & CFS_FAIL_RAND) {

		if (cfs_fail_val < 2 || cfs_rand() % cfs_fail_val > 0)

		if (cfs_fail_val < 2 || prandom_u32_max(cfs_fail_val) > 0)

			return 0;

	}

drivers/staging/lustre/lnet/lnet/net_fault.c

+20 −18
Original line number Diff line number Diff line
@@ -170,10 +170,10 @@ lnet_drop_rule_add(struct lnet_fault_attr *attr) 
	rule->dr_attr = *attr;

	if (attr->u.drop.da_interval) {

		rule->dr_time_base = cfs_time_shift(attr->u.drop.da_interval);

		rule->dr_drop_time = cfs_time_shift(cfs_rand() %

						    attr->u.drop.da_interval);

		rule->dr_drop_time = cfs_time_shift(

			prandom_u32_max(attr->u.drop.da_interval));

	} else {

		rule->dr_drop_at = cfs_rand() % attr->u.drop.da_rate;

		rule->dr_drop_at = prandom_u32_max(attr->u.drop.da_rate);

	}



	lnet_net_lock(LNET_LOCK_EX);
@@ -277,10 +277,10 @@ lnet_drop_rule_reset(void) 


		memset(&rule->dr_stat, 0, sizeof(rule->dr_stat));

		if (attr->u.drop.da_rate) {

			rule->dr_drop_at = cfs_rand() % attr->u.drop.da_rate;

			rule->dr_drop_at = prandom_u32_max(attr->u.drop.da_rate);

		} else {

			rule->dr_drop_time = cfs_time_shift(cfs_rand() %

						attr->u.drop.da_interval);

			rule->dr_drop_time = cfs_time_shift(

				prandom_u32_max(attr->u.drop.da_interval));

			rule->dr_time_base = cfs_time_shift(attr->u.drop.da_interval);

		}

		spin_unlock(&rule->dr_lock);
@@ -315,8 +315,8 @@ drop_rule_match(struct lnet_drop_rule *rule, lnet_nid_t src, 
				rule->dr_time_base = now;



			rule->dr_drop_time = rule->dr_time_base +

					     cfs_time_seconds(cfs_rand() %

						attr->u.drop.da_interval);

				cfs_time_seconds(

					prandom_u32_max(attr->u.drop.da_interval));

			rule->dr_time_base += cfs_time_seconds(attr->u.drop.da_interval);



			CDEBUG(D_NET, "Drop Rule %s->%s: next drop : %lu\n",
@@ -330,7 +330,7 @@ drop_rule_match(struct lnet_drop_rule *rule, lnet_nid_t src, 


		if (!do_div(rule->dr_stat.fs_count, attr->u.drop.da_rate)) {

			rule->dr_drop_at = rule->dr_stat.fs_count +

					   cfs_rand() % attr->u.drop.da_rate;

				prandom_u32_max(attr->u.drop.da_rate);

			CDEBUG(D_NET, "Drop Rule %s->%s: next drop: %lu\n",

			       libcfs_nid2str(attr->fa_src),

			       libcfs_nid2str(attr->fa_dst), rule->dr_drop_at);
@@ -483,8 +483,9 @@ delay_rule_match(struct lnet_delay_rule *rule, lnet_nid_t src, 
				rule->dl_time_base = now;



			rule->dl_delay_time = rule->dl_time_base +

					     cfs_time_seconds(cfs_rand() %

						attr->u.delay.la_interval);

				cfs_time_seconds(

					prandom_u32_max(

						attr->u.delay.la_interval));

			rule->dl_time_base += cfs_time_seconds(attr->u.delay.la_interval);



			CDEBUG(D_NET, "Delay Rule %s->%s: next delay : %lu\n",
@@ -498,7 +499,7 @@ delay_rule_match(struct lnet_delay_rule *rule, lnet_nid_t src, 
		/* generate the next random rate sequence */

		if (!do_div(rule->dl_stat.fs_count, attr->u.delay.la_rate)) {

			rule->dl_delay_at = rule->dl_stat.fs_count +

					    cfs_rand() % attr->u.delay.la_rate;

				prandom_u32_max(attr->u.delay.la_rate);

			CDEBUG(D_NET, "Delay Rule %s->%s: next delay: %lu\n",

			       libcfs_nid2str(attr->fa_src),

			       libcfs_nid2str(attr->fa_dst), rule->dl_delay_at);
@@ -771,10 +772,10 @@ lnet_delay_rule_add(struct lnet_fault_attr *attr) 
	rule->dl_attr = *attr;

	if (attr->u.delay.la_interval) {

		rule->dl_time_base = cfs_time_shift(attr->u.delay.la_interval);

		rule->dl_delay_time = cfs_time_shift(cfs_rand() %

						     attr->u.delay.la_interval);

		rule->dl_delay_time = cfs_time_shift(

			prandom_u32_max(attr->u.delay.la_interval));

	} else {

		rule->dl_delay_at = cfs_rand() % attr->u.delay.la_rate;

		rule->dl_delay_at = prandom_u32_max(attr->u.delay.la_rate);

	}



	rule->dl_msg_send = -1;
@@ -920,10 +921,11 @@ lnet_delay_rule_reset(void) 


		memset(&rule->dl_stat, 0, sizeof(rule->dl_stat));

		if (attr->u.delay.la_rate) {

			rule->dl_delay_at = cfs_rand() % attr->u.delay.la_rate;

			rule->dl_delay_at = prandom_u32_max(attr->u.delay.la_rate);

		} else {

			rule->dl_delay_time = cfs_time_shift(cfs_rand() %

						attr->u.delay.la_interval);

			rule->dl_delay_time =

				cfs_time_shift(prandom_u32_max(

						       attr->u.delay.la_interval));

			rule->dl_time_base = cfs_time_shift(attr->u.delay.la_interval);

		}

		spin_unlock(&rule->dl_lock);

drivers/staging/lustre/lnet/lnet/router.c

+2 −2
Original line number Diff line number Diff line
@@ -277,8 +277,8 @@ lnet_add_route_to_rnet(struct lnet_remotenet *rnet, struct lnet_route *route) 
		len++;

	}



	/* len+1 positions to add a new entry, also prevents division by 0 */

	offset = cfs_rand() % (len + 1);

	/* len+1 positions to add a new entry */

	offset = prandom_u32_max(len + 1);

	list_for_each(e, &rnet->lrn_routes) {

		if (!offset)

			break;

drivers/staging/lustre/lustre/mgc/mgc_request.c

+2 −2
Original line number Diff line number Diff line
@@ -523,7 +523,7 @@ static void do_requeue(struct config_llog_data *cld) 
 * in order to not flood the MGS.

 */

#define MGC_TIMEOUT_MIN_SECONDS   5

#define MGC_TIMEOUT_RAND_CENTISEC 0x1ff /* ~500 */

#define MGC_TIMEOUT_RAND_CENTISEC 500



static int mgc_requeue_thread(void *data)

{
@@ -537,7 +537,7 @@ static int mgc_requeue_thread(void *data) 
	while (!(rq_state & RQ_STOP)) {

		struct l_wait_info lwi;

		struct config_llog_data *cld, *cld_prev;

		int rand = cfs_rand() & MGC_TIMEOUT_RAND_CENTISEC;

		int rand = prandom_u32_max(MGC_TIMEOUT_RAND_CENTISEC);

		int to;



		/* Any new or requeued lostlocks will change the state */