Re: [PATCH] virtio-blk: make the queue depth configurable

From: Joe Perches
Date: Wed Mar 19 2014 - 02:51:21 EST


On Wed, 2014-03-19 at 17:07 +1030, Rusty Russell wrote:

> Summary of http://lkml.org/lkml/2014/3/14/363 :
>
> Ted: module_param(queue_depth, int, 444)
> Joe: 0444!
> Rusty: User perms >= group perms >= other perms?
> Joe: CLASS_ATTR, DEVICE_ATTR, SENSOR_ATTR and SENSOR_ATTR_2?

<smile>

Adding:

Rusty: Bikeshedding
Joe: Missing ((perm) & 2) ?

[]

> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 471090093c67..945afeb3058a 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -842,4 +842,13 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
> # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
> #endif
>
> +/* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
> +#define VERIFY_OCTAL_PERMISSIONS(perms) \
> + ((__builtin_constant_p(perms) ? \
> + BUILD_BUG_ON_ZERO((perms) < 0) + \
> + BUILD_BUG_ON_ZERO((perms) > 0777) + \
> + /* User perms >= group perms >= other perms */ \
> + BUILD_BUG_ON_ZERO(((perms) >> 6) < (((perms) >> 3) & 7)) + \
> + BUILD_BUG_ON_ZERO((((perms) >> 3) & 7) < ((perms) & 7)): 0) + \
> + (perms))
> #endif
> diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
> index 175f6995d1af..204a67743804 100644
> --- a/include/linux/moduleparam.h
> +++ b/include/linux/moduleparam.h
> @@ -186,14 +186,12 @@ struct kparam_array
> parameters. */
> #define __module_param_call(prefix, name, ops, arg, perm, level) \
> /* Default value instead of permissions? */ \
> - static int __param_perm_check_##name __attribute__((unused)) = \
> - BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \

Now missing test for ((perm) & 2)

Dunno if that was ever necessary.

> - + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \
> - static const char __param_str_##name[] = prefix #name; \
> + static const char __param_str_##name[] = prefix #name; \
> static struct kernel_param __moduleparam_const __param_##name \
> __used \
> __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
> - = { __param_str_##name, ops, perm, level, { arg } }
> + = { __param_str_##name, ops, VERIFY_OCTAL_PERMISSIONS(perm), \
> + level, { arg } }


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