[PATCH 1/5] random: fix try_to_generate_entropy() if no further cpus set

From: Vernon Yang
Date: Mon Mar 06 2023 - 11:20:38 EST


After commit 596ff4a09b89 ("cpumask: re-introduce constant-sized cpumask
optimizations"), when NR_CPUS <= BITS_PER_LONG, small_cpumask_bits used
a macro instead of variable-sized for efficient.

If no further cpus set, the cpumask_next() returns small_cpumask_bits,
it must greater than or equal to nr_cpumask_bits, so fix it to correctly.

Signed-off-by: Vernon Yang <vernon2gm@xxxxxxxxx>
---
drivers/char/random.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index ce3ccd172cc8..d76f12a5f74f 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1311,7 +1311,7 @@ static void __cold try_to_generate_entropy(void)
/* Basic CPU round-robin, which avoids the current CPU. */
do {
cpu = cpumask_next(cpu, &timer_cpus);
- if (cpu == nr_cpumask_bits)
+ if (cpu >= nr_cpumask_bits)
cpu = cpumask_first(&timer_cpus);
} while (cpu == smp_processor_id() && num_cpus > 1);

--
2.34.1