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| author | Kees Cook <keescook@chromium.org> | 2023-09-13 16:54:14 -0700 |
|---|---|---|
| committer | Luis Chamberlain <mcgrof@kernel.org> | 2023-11-01 13:03:02 -0700 |
| commit | 2c7ccb3c362bc86aeb3e52d6fbf15f7f480ca961 (patch) | |
| tree | 36a903e41a0afed171c891bc7fbae14fe1473dbe | |
| parent | 7d461b291e65938f15f56fe58da2303b07578a76 (diff) | |
| download | lwn-2c7ccb3c362bc86aeb3e52d6fbf15f7f480ca961.tar.gz lwn-2c7ccb3c362bc86aeb3e52d6fbf15f7f480ca961.zip | |
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/
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Johan Hovold <johan@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Nick Desaulniers <ndesaulniers@gooogle.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Joe Perches <joe@perches.com>
Cc: linux-modules@vger.kernel.org
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
| -rw-r--r-- | include/linux/moduleparam.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index 962cd41a2cb5..d4452f93d060 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -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 }; \ |