kernel/arch/sh/include/asm/mmiowb.h, branch 0x221E-v0.0.1-v6.19Hosts the 0x221E linux distro kernel.https://universe.0xinfinity.dev/distro/kernel/atom?h=0x221E-v0.0.1-v6.192019-04-08T11:00:21Zsh/mmiowb: Add unconditional mmiowb() to arch_spin_unlock()2019-04-08T11:00:21ZWill Deaconwill.deacon@arm.com2019-02-22T13:37:21Zurn:sha1:e9e8543fecd2e1ca53616ba82fbd55a25cd2ab8a
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>