iopoll: avoid -Wint-in-bool-context warning
authorArnd Bergmann <arnd@arndb.de>
Fri, 17 Nov 2017 23:27:13 +0000 (15:27 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 18 Nov 2017 00:10:01 +0000 (16:10 -0800)
commitd15809f3649e2ee04713a9dba9aa7bd2c208ad82
tree3ae672852807108b72b643d8deaaef7520f93382
parent1e6270d07cde9bfbc27f8d0f16b323cf3a3b63dd
iopoll: avoid -Wint-in-bool-context warning

When we pass the result of a multiplication as the timeout or the delay,
we can get a warning from gcc-7:

  drivers/mmc/host/bcm2835.c:596:149: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]
  drivers/mfd/arizona-core.c:247:195: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]
  drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c:49:27: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]

The warning is a bit questionable inside of a macro, but this is
intentional on the side of the gcc developers.  It is also an indication
of another problem: we evaluate the timeout and sleep arguments multiple
times, which can have undesired side-effects when those are complex
expressions.

This changes the two iopoll variants to use local variables for storing
copies of the timeouts.  This adds some more type safety, and avoids
both the double-evaluation and the gcc warning.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81484
Link: http://lkml.kernel.org/r/20170726133756.2161367-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20171102114048.1526955-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/iopoll.h