x86: atomic64: Make atomic_read() type-safe
commit3217120873598533234b6dedda9c371ce30001d0
authorIngo Molnar <mingo@elte.hu>
Fri, 3 Jul 2009 11:06:01 +0000 (3 13:06 +0200)
committerIngo Molnar <mingo@elte.hu>
Fri, 3 Jul 2009 11:26:45 +0000 (3 13:26 +0200)
tree3aed0bb4a98bbe2553d9216fa6c965be86e3d8fb
parent3ac805d2afd3fa4a07cb5bcf352fd7fa83f28935
x86: atomic64: Make atomic_read() type-safe

Linus noticed that atomic64_xchg() uses atomic_read(), which
happens to work because atomic_read() is a macro so the
.counter value gets u64-read on 32-bit too - but this is really
bogus and serious bugs are waiting to happen.

Change atomic_read() to be a type-safe inline, and this exposes
the atomic64 bogosity as well:

  arch/x86/lib/atomic64_32.c: In function ‘atomic64_xchg’:
  arch/x86/lib/atomic64_32.c:39: warning: passing argument 1 of ‘atomic_read’ from incompatible pointer type

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/include/asm/atomic_32.h