On 14 November 2014 16:43, Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote: > 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. > Isn't that a much more widespread problem if in_interrupt() yields true while no interrupt is being served? > Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> > > 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@xxxxxxxxxxxxxxxxxxx> > Home Page: http://gondor.apana.org.au/~herbert/ > PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html