module: Clarify documentation of module_param_call()
PATCH v2 1/1 module: Clarify documentation of module_param_call()
Commit 9bbb9e5a3310 ("param: use ops in struct kernel_param, rather than get and set fns directly") added the comment that module_param_call() was deprecated, during a large scale refactoring to bring sanity to type casting back then. In 2017 following more cleanups, it became useful again as it wraps a common pattern of creating an ops struct for a given get/set pair:
b2f270e87473 ("module: Prepare to convert all module_param_call() prototypes") ece1996a21ee ("module: Do not paper over type mismatches in module_param_call()")
static const struct kernel_param_ops __param_ops_##name = \
{ .flags = 0, .set = _set, .get = _get }; \
__module_param_call(MODULE_PARAM_PREFIX, \
name, &__param_ops_##name, arg, perm, -1, 0)
__module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0)Many users of module_param_cb() appear to be almost universally open-coding the same thing that module_param_call() does now. Don't discourage[1] people from using module_param_call(): clarify the comment to show that module_param_cb() is useful if you repeatedly use the same pair of get/set functions.
[1] https://lore.kernel.org/lkml/202308301546.5C789E5EC@keescook/
---
Luis, I note that include/linux/moduleparam.h isn't in the MAINTAINERS file pattern. Perhaps you want to use include/linux/module*.h?
--- include/linux/moduleparam.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
include/linux/moduleparam.h +5 -1
@@ -293,7 +293,11 @@ struct kparam_array = { __param_str_##name, THIS_MODULE, ops, \ VERIFY_OCTAL_PERMISSIONS(perm), level, flags, { arg } } -/* Obsolete - use module_param_cb() */ +/* +* Useful for describing a set/get pair used only once (i.e. for this +* parameter). For repeated set/get pairs (i.e. the same struct +* kernel_param_ops), use module_param_cb() instead. +*/ #define module_param_call (name, _set, _get, arg, perm) \ static const struct kernel_param_ops __param_ops_##name = \ { .flags = 0, .set = _set, .get = _get }; \
Signature · 1 line
2.34.1
Luis Chamberlain
maintainerQuoted 25 lines · Kees Cook
Commit
9bbb9e5a3310("param: use ops in structkernel_param, rather than get and set fns directly") added the comment thatmodule_param_call()was deprecated, during a large scale refactoring to bring sanity to type casting back then. In 2017 following more cleanups, it became useful again as it wraps a common pattern of creating an ops struct for a given get/set pair:
b2f270e87473("module: Prepare to convert allmodule_param_call()prototypes")ece1996a21ee("module: Do not paper over type mismatches inmodule_param_call()")static const struct kernel_param_ops __param_ops_##name = \ { .flags = 0, .set = _set, .get = _get }; \ __module_param_call(MODULE_PARAM_PREFIX, \ name, &__param_ops_##name, arg, perm, -1, 0) __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0)Many users of
module_param_cb()appear to be almost universally open-coding the same thing thatmodule_param_call()does now. Don't discourage[1] people from usingmodule_param_call(): clarify the comment to show thatmodule_param_cb()is useful if you repeatedly use the same pair of get/set functions.[1] https://lore.kernel.org/lkml/202308301546.5C789E5EC@keescook/
Quoted 10 lines
Cc Luis Chamberlain <[email protected]>Cc Johan Hovold <[email protected]>Cc Jessica Yu <[email protected]>Cc Sagi Grimberg <[email protected]>Cc Nick Desaulniers <[email protected]>Cc Miguel Ojeda <[email protected]>Cc Joe Perches <[email protected]>Reviewed-by Miguel Ojeda <[email protected]>Signed-off-by Kees Cook <[email protected]>
Applied and pushed to modules-next, thanks
Quoted 3 lines
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Luis, I note thatinclude/linux/moduleparam.hisn't in theMAINTAINERSfile pattern. Perhaps you want to useinclude/linux/module*.h?
Sent patch! Thanks!
Luis