2024-05-31 11:41:36

by Zhiguo Niu

Subject: [PATCH] block: uapi: Fix compliation warning of using IOPRIO_PRIO_DATA

Generally, the input of IOPRIO_PRIO_DATA has 16 bits. If use format "%d"
to printk IOPRIO_PRIO_DATA, there will be the following warning or error.

fs/f2fs/sysfs.c:348:31: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘long unsigned int’ [-Wformat=]
return sysfs_emit(buf, "%s,%d\n",
~^
%ld

This is because the output of IOPRIO_PRIO_DATA is converted to "UL" from
IOPRIO_PRIO_MASK, which is not reasonable. unsigned int is more suitable.

Signed-off-by: Zhiguo Niu <[email protected]>
---
include/uapi/linux/ioprio.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/uapi/linux/ioprio.h b/include/uapi/linux/ioprio.h
index bee2bdb0..9ead07f 100644
--- a/include/uapi/linux/ioprio.h
+++ b/include/uapi/linux/ioprio.h
@@ -11,7 +11,7 @@
#define IOPRIO_CLASS_SHIFT 13
#define IOPRIO_NR_CLASSES 8
#define IOPRIO_CLASS_MASK (IOPRIO_NR_CLASSES - 1)
-#define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1)
+#define IOPRIO_PRIO_MASK ((1U << IOPRIO_CLASS_SHIFT) - 1)

#define IOPRIO_PRIO_CLASS(ioprio) \
(((ioprio) >> IOPRIO_CLASS_SHIFT) & IOPRIO_CLASS_MASK)
--
1.9.1

2024-05-31 20:21:30

by Bart Van Assche

Subject: Re: [PATCH] block: uapi: Fix compliation warning of using IOPRIO_PRIO_DATA

On 5/31/24 04:31, Zhiguo Niu wrote:
> Generally, the input of IOPRIO_PRIO_DATA has 16 bits. If use format "%d"
> to printk IOPRIO_PRIO_DATA, there will be the following warning or error.
>
> fs/f2fs/sysfs.c:348:31: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘long unsigned int’ [-Wformat=]
> return sysfs_emit(buf, "%s,%d\n",
> ~^
> %ld
>
> This is because the output of IOPRIO_PRIO_DATA is converted to "UL" from
> IOPRIO_PRIO_MASK, which is not reasonable. unsigned int is more suitable.
>
> Signed-off-by: Zhiguo Niu <[email protected]>
> ---
> include/uapi/linux/ioprio.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/ioprio.h b/include/uapi/linux/ioprio.h
> index bee2bdb0..9ead07f 100644
> --- a/include/uapi/linux/ioprio.h
> +++ b/include/uapi/linux/ioprio.h
> @@ -11,7 +11,7 @@
> #define IOPRIO_CLASS_SHIFT 13
> #define IOPRIO_NR_CLASSES 8
> #define IOPRIO_CLASS_MASK (IOPRIO_NR_CLASSES - 1)
> -#define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1)
> +#define IOPRIO_PRIO_MASK ((1U << IOPRIO_CLASS_SHIFT) - 1)
>
> #define IOPRIO_PRIO_CLASS(ioprio) \
> (((ioprio) >> IOPRIO_CLASS_SHIFT) & IOPRIO_CLASS_MASK)

This change is safe even if the mask is applied to an expression with more bits
than an int because of the integer promotion rules. Hence:

Reviewed-by: Bart Van Assche <[email protected]>