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Subjectsimd: Allow simd use in kernel threads with softirqs disabled
While working on the cryptd request reordering problem, I noticed
an anomaly where kernel threads are normally allowed to use simd
per may_use_simd, but as soon as you disable softirqs, they suddenly
lose that ability for no good reason.

The problem is that in_interrupt does not distinguish between
softirq processing and simply having softirqs disabled. This
patch creates a new helper in_serving_interrupt which makes that
distinction. It then uses this in all current implementations
of may_use_simd.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index a9a4229..6cdaa852 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -63,7 +63,7 @@ static inline bool interrupted_user_mode(void)
*/
bool irq_fpu_usable(void)
{
- return !in_interrupt() ||
+ return !in_serving_interrupt() ||
interrupted_user_mode() ||
interrupted_kernel_fpu_idle();
}
diff --git a/include/asm-generic/simd.h b/include/asm-generic/simd.h
index f57eb7b..74e0b05 100644
--- a/include/asm-generic/simd.h
+++ b/include/asm-generic/simd.h
@@ -10,5 +10,5 @@
*/
static __must_check inline bool may_use_simd(void)
{
- return !in_interrupt();
+ return !in_serving_interrupt();
}
diff --git a/include/linux/preempt_mask.h b/include/linux/preempt_mask.h
index dbeec4d..18f3b46 100644
--- a/include/linux/preempt_mask.h
+++ b/include/linux/preempt_mask.h
@@ -65,6 +65,8 @@
#define in_softirq() (softirq_count())
#define in_interrupt() (irq_count())
#define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET)
+#define in_serving_interrupt() (irq_count() & (HARDIRQ_MASK | \
+ SOFTIRQ_OFFSET | NMI_MASK))

/*
* Are we in NMI context?
Thanks,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt


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