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s390/uaccess, locking/static_keys: employ static_branch_likely()

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Use the new static_branch_likely() primitive to make sure that the
most likely case is executed without taking an unconditional branch.
This wasn't possible with the old jump label primitives.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20150729064600.GB3953@osiris
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Heiko Carstens 2015-07-29 08:31:24 +02:00 committed by Ingo Molnar
parent 3bbfafb77a
commit ed79e94673
1 changed files with 6 additions and 6 deletions
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12
arch/s390/lib/uaccess.c
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@ -15,7 +15,7 @@
#include <asm/mmu_context.h>
#include <asm/facility.h>
static struct static_key have_mvcos = STATIC_KEY_INIT_FALSE;
static DEFINE_STATIC_KEY_FALSE(have_mvcos);
static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
unsigned long size)
@ -104,7 +104,7 @@ static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (static_key_false(&have_mvcos))
if (static_branch_likely(&have_mvcos))
return copy_from_user_mvcos(to, from, n);
return copy_from_user_mvcp(to, from, n);
}
@ -177,7 +177,7 @@ static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
{
if (static_key_false(&have_mvcos))
if (static_branch_likely(&have_mvcos))
return copy_to_user_mvcos(to, from, n);
return copy_to_user_mvcs(to, from, n);
}
@ -240,7 +240,7 @@ static inline unsigned long copy_in_user_mvc(void __user *to, const void __user
unsigned long __copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
if (static_key_false(&have_mvcos))
if (static_branch_likely(&have_mvcos))
return copy_in_user_mvcos(to, from, n);
return copy_in_user_mvc(to, from, n);
}
@ -312,7 +312,7 @@ static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
unsigned long __clear_user(void __user *to, unsigned long size)
{
if (static_key_false(&have_mvcos))
if (static_branch_likely(&have_mvcos))
return clear_user_mvcos(to, size);
return clear_user_xc(to, size);
}
@ -386,7 +386,7 @@ early_param("uaccess_primary", parse_uaccess_pt);
static int __init uaccess_init(void)
{
if (!uaccess_primary && test_facility(27))
static_key_slow_inc(&have_mvcos);
static_branch_enable(&have_mvcos);
return 0;
}
early_initcall(uaccess_init);