• Peter Zijlstra's avatar
    locking/atomic, arch/sh: Implement atomic_fetch_{add,sub,and,or,xor}() · 7d9794e7
    Peter Zijlstra authored
    Implement FETCH-OP atomic primitives, these are very similar to the
    existing OP-RETURN primitives we already have, except they return the
    value of the atomic variable _before_ modification.
    
    This is especially useful for irreversible operations -- such as
    bitops (because it becomes impossible to reconstruct the state prior
    to modification).
    Signed-off-by: default avatarPeter 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: Rich Felker <dalias@libc.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
    Cc: linux-arch@vger.kernel.org
    Cc: linux-kernel@vger.kernel.org
    Cc: linux-sh@vger.kernel.org
    Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
    7d9794e7
atomic.h 1.68 KB