locking/qrwlock: Fix write unlock bug on big endian systems
authorpan xinhui <xinhui.pan@linux.vnet.ibm.com>
Mon, 18 Jul 2016 09:47:39 +0000 (17:47 +0800)
committerIngo Molnar <mingo@kernel.org>
Wed, 10 Aug 2016 12:13:27 +0000 (14:13 +0200)
commit2db34e8bf9a22f4e38b29deccee57457bc0e7d74
tree69f62c648841189e26d1132e65ac465455b55abf
parenta2071cd765637002523798358d2ca441306d708b
locking/qrwlock: Fix write unlock bug on big endian systems

This patch aims to get rid of endianness in queued_write_unlock(). We
want to set  __qrwlock->wmode to NULL, however the address is not
&lock->cnts in big endian machine. That causes queued_write_unlock()
write NULL to the wrong field of __qrwlock.

So implement __qrwlock_write_byte() which returns the correct
__qrwlock->wmode address.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.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: Waiman.Long@hpe.com
Cc: arnd@arndb.de
Cc: boqun.feng@gmail.com
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1468835259-4486-1-git-send-email-xinhui.pan@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
include/asm-generic/qrwlock.h