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 <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Darrick J. Wong <[email protected]> # for xfs
Reviewed-by: SeongJae Park <[email protected]> # for damon
Reviewed-by: Jason Gunthorpe <[email protected]> # for infiniband
Reviewed-by: Russell King (Oracle) <[email protected]> # for arm
Acked-by: Ulf Hansson <[email protected]> # for mmc
Signed-off-by: Jason A. Donenfeld <[email protected]>

1 files changed, 2 insertions, 1 deletions

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) {