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| author | Paul E. McKenney <paulmck@kernel.org> | 2020-02-05 15:34:09 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-02-07 15:34:12 +0100 |
| commit | 1e474b28e78897d0d170fab3b28ba683149cb9ea (patch) | |
| tree | b96998f3ca19bfda3d6ff614367363e7516cbba7 /kernel | |
| parent | smp: Remove superfluous cond_func check in smp_call_function_many_cond() (diff) | |
| download | linux-1e474b28e78897d0d170fab3b28ba683149cb9ea.tar.xz linux-1e474b28e78897d0d170fab3b28ba683149cb9ea.zip | |
smp/up: Make smp_call_function_single() match SMP semantics
In CONFIG_SMP=y kernels, smp_call_function_single() returns -ENXIO when
invoked for a non-existent CPU. In contrast, in CONFIG_SMP=n kernels,
a splat is emitted and smp_call_function_single() otherwise silently
ignores its "cpu" argument, instead pretending that the caller intended
to have something happen on CPU 0. Given that there is now code that
expects smp_call_function_single() to return an error if a bad CPU was
specified, this difference in semantics needs to be addressed.
Bring the semantics of the CONFIG_SMP=n version of
smp_call_function_single() into alignment with its CONFIG_SMP=y
counterpart.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200205143409.GA7021@paulmck-ThinkPad-P72
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/up.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/up.c b/kernel/up.c index 53144d056252..c6f323dcd45b 100644 --- a/kernel/up.c +++ b/kernel/up.c @@ -14,7 +14,8 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, { unsigned long flags; - WARN_ON(cpu != 0); + if (cpu != 0) + return -ENXIO; local_irq_save(flags); func(info); |