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authorYejune Deng <yejune.deng@gmail.com>2021-05-10 16:10:24 +0100
committerPeter Zijlstra <peterz@infradead.org>2021-05-19 10:51:40 +0200
commit570a752b7a9bd03b50ad6420cd7f10092cc11bd3 (patch)
tree848e23fc4dd2a57a0b17f2a8fc5732d70d59e5c2 /lib/smp_processor_id.c
parent00b89fe0197f0c55a045775c11553c0cdb7082fe (diff)
lib/smp_processor_id: Use is_percpu_thread() instead of nr_cpus_allowed
is_percpu_thread() more elegantly handles SMP vs UP, and further checks the presence of PF_NO_SETAFFINITY. This lets us catch cases where check_preemption_disabled() can race with a concurrent sched_setaffinity(). Signed-off-by: Yejune Deng <yejune.deng@gmail.com> [Amended changelog] Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210510151024.2448573-3-valentin.schneider@arm.com
Diffstat (limited to 'lib/smp_processor_id.c')
-rw-r--r--lib/smp_processor_id.c6
1 files changed, 1 insertions, 5 deletions
diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
index 1c1dbd300325..046ac6297c78 100644
--- a/lib/smp_processor_id.c
+++ b/lib/smp_processor_id.c
@@ -19,11 +19,7 @@ unsigned int check_preemption_disabled(const char *what1, const char *what2)
if (irqs_disabled())
goto out;
- /*
- * Kernel threads bound to a single CPU can safely use
- * smp_processor_id():
- */
- if (current->nr_cpus_allowed == 1)
+ if (is_percpu_thread())
goto out;
#ifdef CONFIG_SMP