diff options
| author | Will Deacon <will.deacon@arm.com> | 2019-02-22 14:37:21 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2019-04-08 13:00:21 +0200 |
| commit | e9e8543fecd2e1ca53616ba82fbd55a25cd2ab8a (patch) | |
| tree | a6139b9501c2b950c997f83273fcb5936c77dd2b /arch/sh/include/asm/spinlock-llsc.h | |
| parent | m68k/io: Remove useless definition of mmiowb() (diff) | |
| download | linux-e9e8543fecd2e1ca53616ba82fbd55a25cd2ab8a.tar.xz linux-e9e8543fecd2e1ca53616ba82fbd55a25cd2ab8a.zip | |
sh/mmiowb: Add unconditional mmiowb() to arch_spin_unlock()
The mmiowb() macro is horribly difficult to use and drivers will continue
to work most of the time if they omit a call when it is required.
Rather than rely on driver authors getting this right, push mmiowb() into
arch_spin_unlock() for sh. If this is deemed to be a performance issue,
a subsequent optimisation could make use of ARCH_HAS_MMIOWB to elide
the barrier in cases where no I/O writes were performed inside the
critical section.
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/sh/include/asm/spinlock-llsc.h')
| -rw-r--r-- | arch/sh/include/asm/spinlock-llsc.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/sh/include/asm/spinlock-llsc.h b/arch/sh/include/asm/spinlock-llsc.h index 786ee0fde3b0..7fd929cd2e7a 100644 --- a/arch/sh/include/asm/spinlock-llsc.h +++ b/arch/sh/include/asm/spinlock-llsc.h @@ -47,6 +47,8 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock) { unsigned long tmp; + /* This could be optimised with ARCH_HAS_MMIOWB */ + mmiowb(); __asm__ __volatile__ ( "mov #1, %0 ! arch_spin_unlock \n\t" "mov.l %0, @%1 \n\t" |