Messages in this thread Patch in this message | | | From | Rusty Russell <> | Subject | Re: [PATCH] params: make dashes and underscores in parameter names truly equal | Date | Tue, 18 Oct 2011 14:28:46 +1030 |
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On Thu, 13 Oct 2011 16:41:11 +0200, Michal Schmidt <mschmidt@redhat.com> wrote: > On 10/13/2011 01:28 AM, Rusty Russell wrote: > > Idea is solid, implementation has a few quirks. As the name > > obsolete_checksetup() implies, this was only supposed to be a crutch for > > old __setup() calls. Modern code should be using module_param() or > > core_param(). > > ... instead of __setup()?
Yep.
> No objection to the change in do_early_param() ?
Well, for the moment I've applied that, with parameq and parameqn reimplemented more cleanly. See below.
> > Did you have a specific example? > > The specific example I had in mind was the one from > Documentation/kernel-parameters.txt: > > log_buf_len=1M print-fatal-signals=1 > can also be entered as > log-buf-len=1M print_fatal_signals=1
Oops.
> Let's see how many __setup() parameters there are: > $ git grep -E '^__setup\("' |wc -l > 457 > > Only the ones with a dash or underscore in the name: > $ git grep -E '__setup\(".*[_-].*"' | wc -l > 180 > > It will take some time.
The easy things have already been done ;)
Just do the non-arch ones, first, and see where that gets us.
Thanks! Rusty.
From: Michal Schmidt <mschmidt@redhat.com> Subject: params: make dashes and underscores in parameter names truly equal Date: Mon, 10 Oct 2011 00:03:37 +0200
The user may use "foo-bar" for a kernel parameter defined as "foo_bar". Make sure it works the other way around too.
Apply the equality of dashes and underscores on early_params and __setup params as well.
The example given in Documentation/kernel-parameters.txt indicates that this is the intended behaviour.
With the patch the kernel accepts "log-buf-len=1M" as expected. https://bugzilla.redhat.com/show_bug.cgi?id=744545
Signed-off-by: Michal Schmidt <mschmidt@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (neatened implementations) --- include/linux/moduleparam.h | 20 ++++++++++++++++++++ init/main.c | 4 ++-- kernel/params.c | 21 ++++++++++++++------- 3 files changed, 36 insertions(+), 9 deletions(-)
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -262,6 +262,26 @@ static inline void __kernel_param_unlock .str = &__param_string_##name, 0, perm); \ __MODULE_PARM_TYPE(name, "string") +/** + * parameq - checks if two parameter names match + * @name1: parameter name 1 + * @name2: parameter name 2 + * + * Returns true if the two parameter names are equal. + * Dashes (-) are considered equal to underscores (_). + */ +extern bool parameq(const char *name1, const char *name2); + +/** + * parameqn - checks if two parameter names match + * @name1: parameter name 1 + * @name2: parameter name 2 + * @n: the length to compare + * + * Similar to parameq(), except it compares @n characters. + */ +extern bool parameqn(const char *name1, const char *name2, size_t n); + /* Called on module insert or kernel boot */ extern int parse_args(const char *name, char *args, diff --git a/init/main.c b/init/main.c --- a/init/main.c +++ b/init/main.c @@ -163,7 +163,7 @@ static int __init obsolete_checksetup(ch p = __setup_start; do { int n = strlen(p->str); - if (!strncmp(line, p->str, n)) { + if (parameqn(line, p->str, n)) { if (p->early) { /* Already done in parse_early_param? * (Needs exact match on param part). @@ -392,7 +392,7 @@ static int __init do_early_param(char *p const struct obs_kernel_param *p; for (p = __setup_start; p < __setup_end; p++) { - if ((p->early && strcmp(param, p->str) == 0) || + if ((p->early && parameq(param, p->str)) || (strcmp(param, "console") == 0 && strcmp(p->str, "earlycon") == 0) ) { diff --git a/kernel/params.c b/kernel/params.c --- a/kernel/params.c +++ b/kernel/params.c @@ -67,20 +67,27 @@ static void maybe_kfree_parameter(void * } } -static inline char dash2underscore(char c) +static char dash2underscore(char c) { if (c == '-') return '_'; return c; } -static inline int parameq(const char *input, const char *paramname) +bool parameqn(const char *a, const char *b, size_t n) { - unsigned int i; - for (i = 0; dash2underscore(input[i]) == paramname[i]; i++) - if (input[i] == '\0') - return 1; - return 0; + size_t i; + + for (i = 0; i < n; i++) { + if (dash2underscore(a[i]) != dash2underscore(b[i])) + return false; + } + return true; +} + +bool parameq(const char *a, const char *b) +{ + return parameqn(a, b, strlen(a)+1); } static int parse_one(char *param,
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