From b4bc842802db3314f9a657094da0450a903ea619 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Mon, 7 Feb 2011 16:02:25 -0800 Subject: module: deal with alignment issues in built-in module versions On m68k natural alignment is 2-byte boundary but we are trying to align structures in __modver section on sizeof(void *) boundary. This causes trouble when we try to access elements in this section in array-like fashion when create "version" attributes for built-in modules. Moreover, as DaveM said, we can't reliably put structures into independent objects, put them into a special section, and then expect array access over them (via the section boundaries) after linking the objects together to just "work" due to variable alignment choices in different situations. The only solution that seems to work reliably is to make an array of plain pointers to the objects in question and put those pointers in the special section. Reported-by: Geert Uytterhoeven Signed-off-by: Dmitry Torokhov Signed-off-by: Rusty Russell --- include/linux/module.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'include') diff --git a/include/linux/module.h b/include/linux/module.h index 5de42043dff..4cfebc21169 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -174,10 +174,7 @@ extern struct module __this_module; #define MODULE_VERSION(_version) \ extern ssize_t __modver_version_show(struct module_attribute *, \ struct module *, char *); \ - static struct module_version_attribute __modver_version_attr \ - __used \ - __attribute__ ((__section__ ("__modver"),aligned(sizeof(void *)))) \ - = { \ + static struct module_version_attribute ___modver_attr = { \ .mattr = { \ .attr = { \ .name = "version", \ @@ -187,7 +184,10 @@ extern struct module __this_module; }, \ .module_name = KBUILD_MODNAME, \ .version = _version, \ - } + }; \ + static const struct module_version_attribute \ + __used __attribute__ ((__section__ ("__modver"))) \ + * __moduleparam_const __modver_attr = &___modver_attr #endif /* Optional firmware file (or files) needed by the module -- cgit v1.2.3-70-g09d2 From 9b73a5840c7d5f77e5766626716df13787cb258c Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Mon, 7 Feb 2011 16:02:27 -0800 Subject: module: do not hide __modver_version_show declaration behind ifdef Doing so prevents the following warning from sparse: CHECK kernel/params.c kernel/params.c:817:9: warning: symbol '__modver_version_show' was not declared. Should it be static? since kernel/params.c is never compiled with MODULE being set. Signed-off-by: Dmitry Torokhov Signed-off-by: Rusty Russell --- include/linux/module.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/module.h b/include/linux/module.h index 4cfebc21169..23996ad147e 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -64,6 +64,9 @@ struct module_version_attribute { const char *version; } __attribute__ ((__aligned__(sizeof(void *)))); +extern ssize_t __modver_version_show(struct module_attribute *, + struct module *, char *); + struct module_kobject { struct kobject kobj; @@ -172,8 +175,6 @@ extern struct module __this_module; #define MODULE_VERSION(_version) MODULE_INFO(version, _version) #else #define MODULE_VERSION(_version) \ - extern ssize_t __modver_version_show(struct module_attribute *, \ - struct module *, char *); \ static struct module_version_attribute ___modver_attr = { \ .mattr = { \ .attr = { \ -- cgit v1.2.3-70-g09d2 From a288bd651f4180c224cfddf837a0416157a36661 Mon Sep 17 00:00:00 2001 From: Richard Kennedy Date: Thu, 19 May 2011 16:55:25 -0600 Subject: module: remove 64 bit alignment padding from struct module with CONFIG_TRACE* Reorder struct module to remove 24 bytes of alignment padding on 64 bit builds when the CONFIG_TRACE options are selected. This allows the structure to fit into one fewer cache lines, and its size drops from 592 to 568 on x86_64. Signed-off-by: Richard Kennedy Signed-off-by: Rusty Russell --- include/linux/module.h | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/linux/module.h b/include/linux/module.h index 23996ad147e..65cc6cc73ca 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -368,34 +368,35 @@ struct module struct module_notes_attrs *notes_attrs; #endif + /* The command line arguments (may be mangled). People like + keeping pointers to this stuff */ + char *args; + #ifdef CONFIG_SMP /* Per-cpu data. */ void __percpu *percpu; unsigned int percpu_size; #endif - /* The command line arguments (may be mangled). People like - keeping pointers to this stuff */ - char *args; #ifdef CONFIG_TRACEPOINTS - struct tracepoint * const *tracepoints_ptrs; unsigned int num_tracepoints; + struct tracepoint * const *tracepoints_ptrs; #endif #ifdef HAVE_JUMP_LABEL struct jump_entry *jump_entries; unsigned int num_jump_entries; #endif #ifdef CONFIG_TRACING - const char **trace_bprintk_fmt_start; unsigned int num_trace_bprintk_fmt; + const char **trace_bprintk_fmt_start; #endif #ifdef CONFIG_EVENT_TRACING struct ftrace_event_call **trace_events; unsigned int num_trace_events; #endif #ifdef CONFIG_FTRACE_MCOUNT_RECORD - unsigned long *ftrace_callsites; unsigned int num_ftrace_callsites; + unsigned long *ftrace_callsites; #endif #ifdef CONFIG_MODULE_UNLOAD -- cgit v1.2.3-70-g09d2 From c5be0b2eb1ca05e0cd747f9c0ba552c6ee8827a0 Mon Sep 17 00:00:00 2001 From: Richard Kennedy Date: Thu, 19 May 2011 16:55:25 -0600 Subject: module: reorder kparam_array to remove alignment padding on 64 bit builds Reorder structure kparam_array to remove 8 bytes of alignment padding on 64 bit builds, dropping its size from 40 to 32 bytes. Also update the macro module_param_array_named to initialise the structure using its member names to allow it to be changed without touching all its call sites. 'git grep' finds module_param_array in 1037 places so this patch will save a small amount of data space across many modules. Signed-off-by: Richard Kennedy Signed-off-by: Rusty Russell --- include/linux/moduleparam.h | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index 07b41951e3f..ddaae98c53f 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -67,9 +67,9 @@ struct kparam_string { struct kparam_array { unsigned int max; + unsigned int elemsize; unsigned int *num; const struct kernel_param_ops *ops; - unsigned int elemsize; void *elem; }; @@ -371,8 +371,9 @@ extern int param_get_invbool(char *buffer, const struct kernel_param *kp); */ #define module_param_array_named(name, array, type, nump, perm) \ static const struct kparam_array __param_arr_##name \ - = { ARRAY_SIZE(array), nump, ¶m_ops_##type, \ - sizeof(array[0]), array }; \ + = { .max = ARRAY_SIZE(array), .num = nump, \ + .ops = ¶m_ops_##type, \ + .elemsize = sizeof(array[0]), .elem = array }; \ __module_param_call(MODULE_PARAM_PREFIX, name, \ ¶m_array_ops, \ .arr = &__param_arr_##name, \ -- cgit v1.2.3-70-g09d2 From de4d8d53465483168d6a627d409ee2d09d8e3308 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 19 Apr 2011 21:49:58 +0200 Subject: module: each_symbol_section instead of each_symbol Instead of having a callback function for each symbol in the kernel, have a callback for each array of symbols. This eases the logic when we move to sorted symbols and binary search. Signed-off-by: Rusty Russell Signed-off-by: Alessio Igor Bogani --- include/linux/module.h | 5 +++-- kernel/module.c | 42 +++++++++++++++++++++++++++--------------- 2 files changed, 30 insertions(+), 17 deletions(-) (limited to 'include') diff --git a/include/linux/module.h b/include/linux/module.h index 65cc6cc73ca..49f4ad0ddec 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -477,8 +477,9 @@ const struct kernel_symbol *find_symbol(const char *name, bool warn); /* Walk the exported symbol table */ -bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner, - unsigned int symnum, void *data), void *data); +bool each_symbol_section(bool (*fn)(const struct symsearch *arr, + struct module *owner, + void *data), void *data); /* Returns 0 and fills in value, defined and namebuf, or -ERANGE if symnum out of range. */ diff --git a/kernel/module.c b/kernel/module.c index 0e6f97f43c8..e8aa462301e 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -240,23 +240,24 @@ static bool each_symbol_in_section(const struct symsearch *arr, struct module *owner, bool (*fn)(const struct symsearch *syms, struct module *owner, - unsigned int symnum, void *data), + void *data), void *data) { - unsigned int i, j; + unsigned int j; for (j = 0; j < arrsize; j++) { - for (i = 0; i < arr[j].stop - arr[j].start; i++) - if (fn(&arr[j], owner, i, data)) - return true; + if (fn(&arr[j], owner, data)) + return true; } return false; } /* Returns true as soon as fn returns true, otherwise false. */ -bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner, - unsigned int symnum, void *data), void *data) +bool each_symbol_section(bool (*fn)(const struct symsearch *arr, + struct module *owner, + void *data), + void *data) { struct module *mod; static const struct symsearch arr[] = { @@ -309,7 +310,7 @@ bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner, } return false; } -EXPORT_SYMBOL_GPL(each_symbol); +EXPORT_SYMBOL_GPL(each_symbol_section); struct find_symbol_arg { /* Input */ @@ -323,15 +324,12 @@ struct find_symbol_arg { const struct kernel_symbol *sym; }; -static bool find_symbol_in_section(const struct symsearch *syms, - struct module *owner, - unsigned int symnum, void *data) +static bool check_symbol(const struct symsearch *syms, + struct module *owner, + unsigned int symnum, void *data) { struct find_symbol_arg *fsa = data; - if (strcmp(syms->start[symnum].name, fsa->name) != 0) - return false; - if (!fsa->gplok) { if (syms->licence == GPL_ONLY) return false; @@ -365,6 +363,20 @@ static bool find_symbol_in_section(const struct symsearch *syms, return true; } +static bool find_symbol_in_section(const struct symsearch *syms, + struct module *owner, + void *data) +{ + struct find_symbol_arg *fsa = data; + unsigned int i; + + for (i = 0; i < syms->stop - syms->start; i++) { + if (strcmp(syms->start[i].name, fsa->name) == 0) + return check_symbol(syms, owner, i, data); + } + return false; +} + /* Find a symbol and return it, along with, (optional) crc and * (optional) module which owns it. Needs preempt disabled or module_mutex. */ const struct kernel_symbol *find_symbol(const char *name, @@ -379,7 +391,7 @@ const struct kernel_symbol *find_symbol(const char *name, fsa.gplok = gplok; fsa.warn = warn; - if (each_symbol(find_symbol_in_section, &fsa)) { + if (each_symbol_section(find_symbol_in_section, &fsa)) { if (owner) *owner = fsa.owner; if (crc) -- cgit v1.2.3-70-g09d2 From f02e8a6596b7dc9b2171f7ff5654039ef0950cdc Mon Sep 17 00:00:00 2001 From: Alessio Igor Bogani Date: Thu, 14 Apr 2011 14:59:39 +0200 Subject: module: Sort exported symbols This patch places every exported symbol in its own section (i.e. "___ksymtab+printk"). Thus the linker will use its SORT() directive to sort and finally merge all symbol in the right and final section (i.e. "__ksymtab"). The symbol prefixed archs use an underscore as prefix for symbols. To avoid collision we use a different character to create the temporary section names. This work was supported by a hardware donation from the CE Linux Forum. Signed-off-by: Alessio Igor Bogani Signed-off-by: Rusty Russell (folded in '+' fixup) Tested-by: Dirk Behme --- include/asm-generic/vmlinux.lds.h | 20 ++++++++++---------- include/linux/module.h | 4 ++-- scripts/module-common.lds | 11 +++++++++++ 3 files changed, 23 insertions(+), 12 deletions(-) (limited to 'include') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index bd297a20ab9..b27445e00b6 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -274,70 +274,70 @@ /* Kernel symbol table: Normal symbols */ \ __ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___ksymtab) = .; \ - *(__ksymtab) \ + *(SORT(___ksymtab+*)) \ VMLINUX_SYMBOL(__stop___ksymtab) = .; \ } \ \ /* Kernel symbol table: GPL-only symbols */ \ __ksymtab_gpl : AT(ADDR(__ksymtab_gpl) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___ksymtab_gpl) = .; \ - *(__ksymtab_gpl) \ + *(SORT(___ksymtab_gpl+*)) \ VMLINUX_SYMBOL(__stop___ksymtab_gpl) = .; \ } \ \ /* Kernel symbol table: Normal unused symbols */ \ __ksymtab_unused : AT(ADDR(__ksymtab_unused) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___ksymtab_unused) = .; \ - *(__ksymtab_unused) \ + *(SORT(___ksymtab_unused+*)) \ VMLINUX_SYMBOL(__stop___ksymtab_unused) = .; \ } \ \ /* Kernel symbol table: GPL-only unused symbols */ \ __ksymtab_unused_gpl : AT(ADDR(__ksymtab_unused_gpl) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___ksymtab_unused_gpl) = .; \ - *(__ksymtab_unused_gpl) \ + *(SORT(___ksymtab_unused_gpl+*)) \ VMLINUX_SYMBOL(__stop___ksymtab_unused_gpl) = .; \ } \ \ /* Kernel symbol table: GPL-future-only symbols */ \ __ksymtab_gpl_future : AT(ADDR(__ksymtab_gpl_future) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___ksymtab_gpl_future) = .; \ - *(__ksymtab_gpl_future) \ + *(SORT(___ksymtab_gpl_future+*)) \ VMLINUX_SYMBOL(__stop___ksymtab_gpl_future) = .; \ } \ \ /* Kernel symbol table: Normal symbols */ \ __kcrctab : AT(ADDR(__kcrctab) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___kcrctab) = .; \ - *(__kcrctab) \ + *(SORT(___kcrctab+*)) \ VMLINUX_SYMBOL(__stop___kcrctab) = .; \ } \ \ /* Kernel symbol table: GPL-only symbols */ \ __kcrctab_gpl : AT(ADDR(__kcrctab_gpl) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___kcrctab_gpl) = .; \ - *(__kcrctab_gpl) \ + *(SORT(___kcrctab_gpl+*)) \ VMLINUX_SYMBOL(__stop___kcrctab_gpl) = .; \ } \ \ /* Kernel symbol table: Normal unused symbols */ \ __kcrctab_unused : AT(ADDR(__kcrctab_unused) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___kcrctab_unused) = .; \ - *(__kcrctab_unused) \ + *(SORT(___kcrctab_unused+*)) \ VMLINUX_SYMBOL(__stop___kcrctab_unused) = .; \ } \ \ /* Kernel symbol table: GPL-only unused symbols */ \ __kcrctab_unused_gpl : AT(ADDR(__kcrctab_unused_gpl) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___kcrctab_unused_gpl) = .; \ - *(__kcrctab_unused_gpl) \ + *(SORT(___kcrctab_unused_gpl+*)) \ VMLINUX_SYMBOL(__stop___kcrctab_unused_gpl) = .; \ } \ \ /* Kernel symbol table: GPL-future-only symbols */ \ __kcrctab_gpl_future : AT(ADDR(__kcrctab_gpl_future) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___kcrctab_gpl_future) = .; \ - *(__kcrctab_gpl_future) \ + *(SORT(___kcrctab_gpl_future+*)) \ VMLINUX_SYMBOL(__stop___kcrctab_gpl_future) = .; \ } \ \ diff --git a/include/linux/module.h b/include/linux/module.h index 49f4ad0ddec..d9ca2d5dc6d 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -224,7 +224,7 @@ struct module_use { extern void *__crc_##sym __attribute__((weak)); \ static const unsigned long __kcrctab_##sym \ __used \ - __attribute__((section("__kcrctab" sec), unused)) \ + __attribute__((section("___kcrctab" sec "+" #sym), unused)) \ = (unsigned long) &__crc_##sym; #else #define __CRC_SYMBOL(sym, sec) @@ -239,7 +239,7 @@ struct module_use { = MODULE_SYMBOL_PREFIX #sym; \ static const struct kernel_symbol __ksymtab_##sym \ __used \ - __attribute__((section("__ksymtab" sec), unused)) \ + __attribute__((section("___ksymtab" sec "+" #sym), unused)) \ = { (unsigned long)&sym, __kstrtab_##sym } #define EXPORT_SYMBOL(sym) \ diff --git a/scripts/module-common.lds b/scripts/module-common.lds index 47a1f9ae0ed..0865b3e752b 100644 --- a/scripts/module-common.lds +++ b/scripts/module-common.lds @@ -5,4 +5,15 @@ */ SECTIONS { /DISCARD/ : { *(.discard) } + + __ksymtab : { *(SORT(___ksymtab+*)) } + __ksymtab_gpl : { *(SORT(___ksymtab_gpl+*)) } + __ksymtab_unused : { *(SORT(___ksymtab_unused+*)) } + __ksymtab_unused_gpl : { *(SORT(___ksymtab_unused_gpl+*)) } + __ksymtab_gpl_future : { *(SORT(___ksymtab_gpl_future+*)) } + __kcrctab : { *(SORT(___kcrctab+*)) } + __kcrctab_gpl : { *(SORT(___kcrctab_gpl+*)) } + __kcrctab_unused : { *(SORT(___kcrctab_unused+*)) } + __kcrctab_unused_gpl : { *(SORT(___kcrctab_unused_gpl+*)) } + __kcrctab_gpl_future : { *(SORT(___kcrctab_gpl_future+*)) } } -- cgit v1.2.3-70-g09d2 From 1a94dc35bc5c166d89913dc01a49d27a3c21a455 Mon Sep 17 00:00:00 2001 From: Tim Abbott Date: Thu, 14 Apr 2011 20:00:19 +0200 Subject: lib: Add generic binary search function to the kernel. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There a large number hand-coded binary searches in the kernel (run "git grep search | grep binary" to find many of them). Since in my experience, hand-coding binary searches can be error-prone, it seems worth cleaning this up by providing a generic binary search function. This generic binary search implementation comes from Ksplice. It has the same basic API as the C library bsearch() function. Ksplice uses it in half a dozen places with 4 different comparison functions, and I think our code is substantially cleaner because of this. Signed-off-by: Tim Abbott Extra-bikeshedding-by: Alan Jenkins Extra-bikeshedding-by: AndrĂ© Goddard Rosa Extra-bikeshedding-by: Rusty Russell Signed-off-by: Rusty Russell Signed-off-by: Alessio Igor Bogani Signed-off-by: Rusty Russell --- include/linux/bsearch.h | 9 +++++++++ lib/Makefile | 3 ++- lib/bsearch.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 64 insertions(+), 1 deletion(-) create mode 100644 include/linux/bsearch.h create mode 100644 lib/bsearch.c (limited to 'include') diff --git a/include/linux/bsearch.h b/include/linux/bsearch.h new file mode 100644 index 00000000000..90b1aa86722 --- /dev/null +++ b/include/linux/bsearch.h @@ -0,0 +1,9 @@ +#ifndef _LINUX_BSEARCH_H +#define _LINUX_BSEARCH_H + +#include + +void *bsearch(const void *key, const void *base, size_t num, size_t size, + int (*cmp)(const void *key, const void *elt)); + +#endif /* _LINUX_BSEARCH_H */ diff --git a/lib/Makefile b/lib/Makefile index ef0f2857115..4b49a249064 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -21,7 +21,8 @@ lib-y += kobject.o kref.o klist.o obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \ bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \ - string_helpers.o gcd.o lcm.o list_sort.o uuid.o flex_array.o + string_helpers.o gcd.o lcm.o list_sort.o uuid.o flex_array.o \ + bsearch.o obj-y += kstrtox.o obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o diff --git a/lib/bsearch.c b/lib/bsearch.c new file mode 100644 index 00000000000..5b54758e2af --- /dev/null +++ b/lib/bsearch.c @@ -0,0 +1,53 @@ +/* + * A generic implementation of binary search for the Linux kernel + * + * Copyright (C) 2008-2009 Ksplice, Inc. + * Author: Tim Abbott + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; version 2. + */ + +#include +#include + +/* + * bsearch - binary search an array of elements + * @key: pointer to item being searched for + * @base: pointer to first element to search + * @num: number of elements + * @size: size of each element + * @cmp: pointer to comparison function + * + * This function does a binary search on the given array. The + * contents of the array should already be in ascending sorted order + * under the provided comparison function. + * + * Note that the key need not have the same type as the elements in + * the array, e.g. key could be a string and the comparison function + * could compare the string with the struct's name field. However, if + * the key and elements in the array are of the same type, you can use + * the same comparison function for both sort() and bsearch(). + */ +void *bsearch(const void *key, const void *base, size_t num, size_t size, + int (*cmp)(const void *key, const void *elt)) +{ + size_t start = 0, end = num; + int result; + + while (start < end) { + size_t mid = start + (end - start) / 2; + + result = cmp(key, base + mid * size); + if (result < 0) + end = mid; + else if (result > 0) + start = mid + 1; + else + return (void *)base + mid * size; + } + + return NULL; +} +EXPORT_SYMBOL(bsearch); -- cgit v1.2.3-70-g09d2 From d0f1fed29e6e73d9d17f4c91a5896a4ce3938d45 Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Date: Tue, 19 Apr 2011 12:43:45 +0100 Subject: Add a strtobool function matching semantics of existing in kernel equivalents This is a rename of the usr_strtobool proposal, which was a renamed, relocated and fixed version of previous kstrtobool RFC Signed-off-by: Jonathan Cameron Signed-off-by: Rusty Russell --- include/linux/string.h | 1 + lib/string.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+) (limited to 'include') diff --git a/include/linux/string.h b/include/linux/string.h index a716ee2a8ad..a176db2f2c8 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -123,6 +123,7 @@ extern char **argv_split(gfp_t gfp, const char *str, int *argcp); extern void argv_free(char **argv); extern bool sysfs_streq(const char *s1, const char *s2); +extern int strtobool(const char *s, bool *res); #ifdef CONFIG_BINARY_PRINTF int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args); diff --git a/lib/string.c b/lib/string.c index f71bead1be3..01fad9b203e 100644 --- a/lib/string.c +++ b/lib/string.c @@ -535,6 +535,35 @@ bool sysfs_streq(const char *s1, const char *s2) } EXPORT_SYMBOL(sysfs_streq); +/** + * strtobool - convert common user inputs into boolean values + * @s: input string + * @res: result + * + * This routine returns 0 iff the first character is one of 'Yy1Nn0'. + * Otherwise it will return -EINVAL. Value pointed to by res is + * updated upon finding a match. + */ +int strtobool(const char *s, bool *res) +{ + switch (s[0]) { + case 'y': + case 'Y': + case '1': + *res = true; + break; + case 'n': + case 'N': + case '0': + *res = false; + break; + default: + return -EINVAL; + } + return 0; +} +EXPORT_SYMBOL(strtobool); + #ifndef __HAVE_ARCH_MEMSET /** * memset - Fill a region of memory with the given value -- cgit v1.2.3-70-g09d2