Fix WARN_ON() on bitfield ops

Alexey Dobriyan noticed that the new WARN_ON() semantics that were
introduced by commit 684f978347deb42d180373ac4c427f82ef963171 (to also
return the value to be warned on) didn't compile when given a bitfield,
because the typeof doesn't work for bitfields.

So instead of the typeof trick, use an "int" variable together with a
"!!(x)" expression, as suggested by Al Viro.

To make matters more interesting, Paul Mackerras points out that that is
sub-optimal on Power, but the old asm-coded comparison seems to be buggy
anyway on 32-bit Power if the conditional was 64-bit, so I think there
are more problems there.

Regardless, the new WARN_ON() semantics may have been a bad idea.  But
this at least avoids the more serious complications.

Cc: Alexey Dobriyan <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions