[13/14] iopoll: avoid -Wint-in-bool-context warning

Submitted by Arnd Bergmann on July 14, 2017, 9:31 a.m.

Details

Message ID 20170714093129.1366900-4-arnd@arndb.de
State New
Headers show
Series "gcc-7 warnings" ( rev: 3 2 1 ) in DRI devel

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Commit Message

Arnd Bergmann July 14, 2017, 9:31 a.m.
When we pass the result of a multiplication as the timeout, we
can get a warning:

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]

This is easy to avoid by comparing the timeout to zero instead,
making it a boolean expression.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 include/linux/iopoll.h | 6 ++++--
 include/linux/regmap.h | 2 +-
 2 files changed, 5 insertions(+), 3 deletions(-)

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diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h
index d29e1e21bf3f..7a17ba02253b 100644
--- a/include/linux/iopoll.h
+++ b/include/linux/iopoll.h
@@ -48,7 +48,8 @@ 
 		(val) = op(addr); \
 		if (cond) \
 			break; \
-		if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \
+		if ((timeout_us) > 0 && \
+		    ktime_compare(ktime_get(), timeout) > 0) { \
 			(val) = op(addr); \
 			break; \
 		} \
@@ -82,7 +83,8 @@ 
 		(val) = op(addr); \
 		if (cond) \
 			break; \
-		if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \
+		if ((timeout_us) > 0 && \
+		    ktime_compare(ktime_get(), timeout) > 0) { \
 			(val) = op(addr); \
 			break; \
 		} \
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 1474ab0a3922..0889dbf37161 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -129,7 +129,7 @@  struct reg_sequence {
 			break; \
 		if (cond) \
 			break; \
-		if ((timeout_us) && \
+		if ((timeout_us) > 0 && \
 		    ktime_compare(ktime_get(), __timeout) > 0) { \
 			__ret = regmap_read((map), (addr), &(val)); \
 			break; \

Comments

On Fri, 2017-07-14 at 11:31 +0200, Arnd Bergmann wrote:
> When we pass the result of a multiplication as the timeout, we
> can get a warning:
> 
> 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]
> 
> This is easy to avoid by comparing the timeout to zero instead,
> making it a boolean expression.

Perhaps this is better as != 0 if the multiply is signed.

> diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h
[]
> @@ -48,7 +48,8 @@
>  		(val) = op(addr); \
>  		if (cond) \
>  			break; \
> -		if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \
> +		if ((timeout_us) > 0 && \
> +		    ktime_compare(ktime_get(), timeout) > 0) { \
>  			(val) = op(addr); \
>  			break; \
>  		} \

etc...
On Fri, Jul 14, 2017 at 11:55 AM, Joe Perches <joe@perches.com> wrote:
> On Fri, 2017-07-14 at 11:31 +0200, Arnd Bergmann wrote:
>> When we pass the result of a multiplication as the timeout, we
>> can get a warning:
>>
>> 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]
>>
>> This is easy to avoid by comparing the timeout to zero instead,
>> making it a boolean expression.
>
> Perhaps this is better as != 0 if the multiply is signed.

I thought about that, but decided that as a negative timeout_us already
gives us rather random behavior (ktime_add_us() takes an unsigned
argument), the '>' comparison gives a more well-defined result by
ignoring the timeout.

         Arnd