The patch titled
Subject: iopoll: avoid -Wint-in-bool-context warning
has been added to the -mm tree. Its filename is
iopoll-avoid-wint-in-bool-context-warning.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/iopoll-avoid-wint-in-bool-context-warning.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/iopoll-avoid-wint-in-bool-context-warning.patch
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------------------------------------------------------
From: Arnd Bergmann <arnd@xxxxxxxx>
Subject: 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@xxxxxxxx
Link: http://lkml.kernel.org/r/20171102114048.1526955-1-arnd@xxxxxxxx
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Reviewed-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/iopoll.h | 24 +++++++++++++++---------
1 file changed, 15 insertions(+), 9 deletions(-)
diff -puN include/linux/iopoll.h~iopoll-avoid-wint-in-bool-context-warning include/linux/iopoll.h
--- a/include/linux/iopoll.h~iopoll-avoid-wint-in-bool-context-warning
+++ a/include/linux/iopoll.h
@@ -42,18 +42,21 @@
*/
#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \
({ \
- ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \
- might_sleep_if(sleep_us); \
+ u64 __timeout_us = (timeout_us); \
+ unsigned long __sleep_us = (sleep_us); \
+ ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
+ might_sleep_if((__sleep_us) != 0); \
for (;;) { \
(val) = op(addr); \
if (cond) \
break; \
- if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \
+ if (__timeout_us && \
+ ktime_compare(ktime_get(), __timeout) > 0) { \
(val) = op(addr); \
break; \
} \
- if (sleep_us) \
- usleep_range((sleep_us >> 2) + 1, sleep_us); \
+ if (__sleep_us) \
+ usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
} \
(cond) ? 0 : -ETIMEDOUT; \
})
@@ -77,17 +80,20 @@
*/
#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
({ \
- ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \
+ u64 __timeout_us = (timeout_us); \
+ unsigned long __delay_us = (delay_us); \
+ ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
for (;;) { \
(val) = op(addr); \
if (cond) \
break; \
- if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \
+ if (__timeout_us && \
+ ktime_compare(ktime_get(), __timeout) > 0) { \
(val) = op(addr); \
break; \
} \
- if (delay_us) \
- udelay(delay_us); \
+ if (__delay_us) \
+ udelay(__delay_us); \
} \
(cond) ? 0 : -ETIMEDOUT; \
})
_
Patches currently in -mm which might be from arnd@xxxxxxxx are
iopoll-avoid-wint-in-bool-context-warning.patch
initramfs-use-time64_t-timestamps.patch
pcmcia-badge4-avoid-unused-function-warning.patch
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