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| author | Yejune Deng <yejune.deng@gmail.com> | 2021-05-10 16:10:24 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-05-19 10:51:40 +0200 |
| commit | 570a752b7a9bd03b50ad6420cd7f10092cc11bd3 (patch) | |
| tree | 848e23fc4dd2a57a0b17f2a8fc5732d70d59e5c2 /lib/smp_processor_id.c | |
| parent | 00b89fe0197f0c55a045775c11553c0cdb7082fe (diff) | |
| download | lwn-570a752b7a9bd03b50ad6420cd7f10092cc11bd3.tar.gz lwn-570a752b7a9bd03b50ad6420cd7f10092cc11bd3.zip | |
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.c | 6 |
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 |