kernel: fix a perf build error

Signed-off-by: Felix Fietkau <nbd@nbd.name>

target/linux/generic/pending-5.10/110-perf-jevents-fix-getting-maximum-number-of-fds.patch

@@ -0,0 +1,24 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Tue, 25 May 2021 18:00:34 +0200
+Subject: [PATCH] perf jevents: fix getting maximum number of fds
+
+On some hosts, rlim.rlim_max can be returned as RLIM_INFINITY.
+By casting it to int, it is interpreted as -1, which will cause get_maxfds
+to return 0, causing "Invalid argument" errors in nftw() calls.
+Fix this by casting the second argument of min() to rlim_t instead.
+
+Fixes: 80eeb67fe577 ("perf jevents: Program to convert JSON file")
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/tools/perf/pmu-events/jevents.c
++++ b/tools/perf/pmu-events/jevents.c
+@@ -897,7 +897,7 @@ static int get_maxfds(void)
+ 	struct rlimit rlim;
+
+ 	if (getrlimit(RLIMIT_NOFILE, &rlim) == 0)
+-		return min((int)rlim.rlim_max / 2, 512);
++		return min(rlim.rlim_max / 2, (rlim_t)512);
+
+ 	return 512;
+ }