From: Yandong Zhao <yandong77...@gmail.com>
Operations for contexts where we do not want to do any checks for
preemptions. Unless strictly necessary, always use this_cpu_read()
instead. Because of the kernel_neon_busy here we have to make sure
that it is the current cpu.
Signed-off-by: Yandong Zhao <yandong77...@gmail.com>
---
arch/arm64/include/asm/simd.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/simd.h b/arch/arm64/include/asm/simd.h
index fa8b3fe..8b97f8b 100644
--- a/arch/arm64/include/asm/simd.h
+++ b/arch/arm64/include/asm/simd.h
@@ -29,7 +29,8 @@
static __must_check inline bool may_use_simd(void)
{
/*
- * The raw_cpu_read() is racy if called with preemption enabled.
+ * The this_cpu_read() is racy if called with preemption enabled,
+ * since the task my subsequently migrate to another CPU.
* This is not a bug: kernel_neon_busy is only set when
* preemption is disabled, so we cannot migrate to another CPU
* while it is set, nor can we migrate to a CPU where it is set.
@@ -42,7 +43,7 @@ static __must_check inline bool may_use_simd(void)
* false.
*/
return !in_irq() && !irqs_disabled() && !in_nmi() &&
- !raw_cpu_read(kernel_neon_busy);
+ !this_cpu_read(kernel_neon_busy);
}
#else /* ! CONFIG_KERNEL_MODE_NEON */
--
1.9.1
