Re: [PATCH 3/5] perf_counter: rework ioctl()s
From: Arnd Bergmann
Date: Mon May 11 2009 - 19:59:24 EST
On Friday 08 May 2009, Peter Zijlstra wrote:
> -#define PERF_COUNTER_IOC_ENABLE _IO ('$', 0)
> -#define PERF_COUNTER_IOC_DISABLE _IO ('$', 1)
> +#define PERF_COUNTER_IOC_ENABLE _IOW('$', 0, u32)
> +#define PERF_COUNTER_IOC_DISABLE _IOW('$', 1, u32)
> #define PERF_COUNTER_IOC_REFRESH _IOW('$', 2, u32)
> -#define PERF_COUNTER_IOC_RESET _IO ('$', 3)
> +#define PERF_COUNTER_IOC_RESET _IOW('$', 3, u32)
These ioctl definitions look malformed:
_IOW('$', 0, u32) means that the ioctl will read a u32 in user
space pointed to by (u32 __user *)arg, while what perf_ioctl
actually does is cast arg to a u32. Moreover, exported headers
should use __u32 instead of u32.
PERF_COUNTER_IOC_REFRESH apparently was broken already, this
patch also breaks the other definitions.
Arnd <><
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