selftests/bpf: Fixes for test_maps test

BPF CI has failed 3 times in the last 24 hours. Add retry for ENOMEM.
It's similar to the optimization plan:
commit 2f553b0 ("selftsets/bpf: Retry map update for non-preallocated per-cpu map")

Failed CI:
https://github.com/kernel-patches/bpf/actions/runs/13549227497/job/37868926343
https://github.com/kernel-patches/bpf/actions/runs/13548089029/job/37865812030
https://github.com/kernel-patches/bpf/actions/runs/13553536268/job/37883329296

selftests/bpf: Fixes for test_maps test
Fork 100 tasks to 'test_update_delete'
Fork 100 tasks to 'test_update_delete'
Fork 100 tasks to 'test_update_delete'
Fork 100 tasks to 'test_update_delete'
......
test_task_storage_map_stress_lookup:PASS
test_maps: OK, 0 SKIPPED

Signed-off-by: Jiayuan Chen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>

Author: mrpre

tools/testing/selftests/bpf/test_maps.c

@@ -1396,9 +1396,10 @@ static void test_map_stress(void)
 #define MAX_DELAY_US 50000
 #define MIN_DELAY_RANGE_US 5000
 
-static bool retry_for_again_or_busy(int err)
+static bool can_retry(int err)
 {
-	return (err == EAGAIN || err == EBUSY);
+	return (err == EAGAIN || err == EBUSY ||
+		(err == ENOMEM && map_opts.map_flags == BPF_F_NO_PREALLOC));
 }
 
 int map_update_retriable(int map_fd, const void *key, const void *value, int flags, int attempts,
@@ -1451,12 +1452,12 @@ static void test_update_delete(unsigned int fn, void *data)
 
 		if (do_update) {
 			err = map_update_retriable(fd, &key, &value, BPF_NOEXIST, MAP_RETRIES,
-						   retry_for_again_or_busy);
+						   can_retry);
 			if (err)
 				printf("error %d %d\n", err, errno);
 			assert(err == 0);
 			err = map_update_retriable(fd, &key, &value, BPF_EXIST, MAP_RETRIES,
-						   retry_for_again_or_busy);
+						   can_retry);
 			if (err)
 				printf("error %d %d\n", err, errno);
 			assert(err == 0);