treewide: use get_random_u32_below() instead of deprecated function

This is a simple mechanical transformation done by:

@@
expression E;
@@
- prandom_u32_max
+ get_random_u32_below
  (E)

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Reviewed-by: SeongJae Park <sj@kernel.org> # for damon
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> # for arm
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

7 files changed, 11 insertions, 10 deletions

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index d5d745c3e345..46aa2d65e40a 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -263,7 +263,7 @@ bool icmp_global_allow(void)
 		/* We want to use a credit of one in average, but need to randomize
 		 * it for security reasons.
 		 */
-		credit = max_t(int, credit - prandom_u32_max(3), 0);
+		credit = max_t(int, credit - get_random_u32_below(3), 0);
 		rc = true;
 	}
 	WRITE_ONCE(icmp_global.credit, credit);
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 81be3e0f0e70..c920aa9a62a9 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -213,7 +213,7 @@ static void igmp_stop_timer(struct ip_mc_list *im)
 /* It must be called with locked im->lock */
 static void igmp_start_timer(struct ip_mc_list *im, int max_delay)
 {
-	int tv = prandom_u32_max(max_delay);
+	int tv = get_random_u32_below(max_delay);
 
 	im->tm_running = 1;
 	if (!mod_timer(&im->timer, jiffies+tv+2))
@@ -222,7 +222,7 @@ static void igmp_start_timer(struct ip_mc_list *im, int max_delay)
 
 static void igmp_gq_start_timer(struct in_device *in_dev)
 {
-	int tv = prandom_u32_max(in_dev->mr_maxdelay);
+	int tv = get_random_u32_below(in_dev->mr_maxdelay);
 	unsigned long exp = jiffies + tv + 2;
 
 	if (in_dev->mr_gq_running &&
@@ -236,7 +236,7 @@ static void igmp_gq_start_timer(struct in_device *in_dev)
 
 static void igmp_ifc_start_timer(struct in_device *in_dev, int delay)
 {
-	int tv = prandom_u32_max(delay);
+	int tv = get_random_u32_below(delay);
 
 	if (!mod_timer(&in_dev->mr_ifc_timer, jiffies+tv+2))
 		in_dev_hold(in_dev);
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 4e84ed21d16f..f22051219b50 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -314,7 +314,7 @@ other_half_scan:
 	if (likely(remaining > 1))
 		remaining &= ~1U;
 
-	offset = prandom_u32_max(remaining);
+	offset = get_random_u32_below(remaining);
 	/* __inet_hash_connect() favors ports having @low parity
 	 * We do the opposite to not pollute connect() users.
 	 */
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index d3dc28156622..a879ec1a267d 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -1037,7 +1037,7 @@ ok:
 	 * on low contention the randomness is maximal and on high contention
 	 * it may be inexistent.
 	 */
-	i = max_t(int, i, prandom_u32_max(8) * 2);
+	i = max_t(int, i, get_random_u32_below(8) * 2);
 	WRITE_ONCE(table_perturb[index], READ_ONCE(table_perturb[index]) + i + 2);
 
 	/* Head lock still held and bh's disabled */
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index cd1fa9f70f1a..de6e3515ab4f 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -471,7 +471,7 @@ static u32 ip_idents_reserve(u32 hash, int segs)
 	old = READ_ONCE(*p_tstamp);
 
 	if (old != now && cmpxchg(p_tstamp, old, now) == old)
-		delta = prandom_u32_max(now - old);
+		delta = get_random_u32_below(now - old);
 
 	/* If UBSAN reports an error there, please make sure your compiler
 	 * supports -fno-strict-overflow before reporting it that was a bug
@@ -689,7 +689,7 @@ static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
 	} else {
 		/* Randomize max depth to avoid some side channels attacks. */
 		int max_depth = FNHE_RECLAIM_DEPTH +
-				prandom_u32_max(FNHE_RECLAIM_DEPTH);
+				get_random_u32_below(FNHE_RECLAIM_DEPTH);
 
 		while (depth > max_depth) {
 			fnhe_remove_oldest(hash);
diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c
index 54eec33c6e1c..d2c470524e58 100644
--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -618,7 +618,7 @@ static void bbr_reset_probe_bw_mode(struct sock *sk)
 	struct bbr *bbr = inet_csk_ca(sk);
 
 	bbr->mode = BBR_PROBE_BW;
-	bbr->cycle_idx = CYCLE_LEN - 1 - prandom_u32_max(bbr_cycle_rand);
+	bbr->cycle_idx = CYCLE_LEN - 1 - get_random_u32_below(bbr_cycle_rand);
 	bbr_advance_cycle_phase(sk);	/* flip to next phase of gain cycle */
 }
 
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 0640453fce54..3b076e5ba932 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3646,7 +3646,8 @@ static void tcp_send_challenge_ack(struct sock *sk)
 		u32 half = (ack_limit + 1) >> 1;
 
 		WRITE_ONCE(net->ipv4.tcp_challenge_timestamp, now);
-		WRITE_ONCE(net->ipv4.tcp_challenge_count, half + prandom_u32_max(ack_limit));
+		WRITE_ONCE(net->ipv4.tcp_challenge_count,
+			   half + get_random_u32_below(ack_limit));
 	}
 	count = READ_ONCE(net->ipv4.tcp_challenge_count);
 	if (count > 0) {