From 35edd9103c84f2b37f63227d12765c38f30495c5 Mon Sep 17 00:00:00 2001 From: Paul Gortmaker Date: Wed, 16 Nov 2011 23:51:05 -0500 Subject: bug: consolidate BUILD_BUG_ON with other bug code The support for BUILD_BUG in linux/kernel.h predates the addition of linux/bug.h -- with this chunk off separate, you can run into situations where a person gets a compile fail even when they've included linux/bug.h, like this: CC lib/string.o lib/string.c: In function 'strlcat': lib/string.c:225:2: error: implicit declaration of function 'BUILD_BUG_ON' make[2]: *** [lib/string.o] Error 1 $ $ grep linux/bug.h lib/string.c #include $ Since the above violates the principle of least surprise, move the BUG chunks from kernel.h to bug.h so it is all together. Signed-off-by: Paul Gortmaker --- include/linux/kernel.h | 61 -------------------------------------------------- 1 file changed, 61 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index e8343422240..5dba983b8d6 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -662,67 +662,6 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } const typeof( ((type *)0)->member ) *__mptr = (ptr); \ (type *)( (char *)__mptr - offsetof(type,member) );}) -#ifdef __CHECKER__ -#define BUILD_BUG_ON_NOT_POWER_OF_2(n) -#define BUILD_BUG_ON_ZERO(e) (0) -#define BUILD_BUG_ON_NULL(e) ((void*)0) -#define BUILD_BUG_ON(condition) -#define BUILD_BUG() (0) -#else /* __CHECKER__ */ - -/* Force a compilation error if a constant expression is not a power of 2 */ -#define BUILD_BUG_ON_NOT_POWER_OF_2(n) \ - BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0)) - -/* Force a compilation error if condition is true, but also produce a - result (of value 0 and type size_t), so the expression can be used - e.g. in a structure initializer (or where-ever else comma expressions - aren't permitted). */ -#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); })) -#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); })) - -/** - * BUILD_BUG_ON - break compile if a condition is true. - * @condition: the condition which the compiler should know is false. - * - * If you have some code which relies on certain constants being equal, or - * other compile-time-evaluated condition, you should use BUILD_BUG_ON to - * detect if someone changes it. - * - * The implementation uses gcc's reluctance to create a negative array, but - * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments - * to inline functions). So as a fallback we use the optimizer; if it can't - * prove the condition is false, it will cause a link error on the undefined - * "__build_bug_on_failed". This error message can be harder to track down - * though, hence the two different methods. - */ -#ifndef __OPTIMIZE__ -#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)])) -#else -extern int __build_bug_on_failed; -#define BUILD_BUG_ON(condition) \ - do { \ - ((void)sizeof(char[1 - 2*!!(condition)])); \ - if (condition) __build_bug_on_failed = 1; \ - } while(0) -#endif - -/** - * BUILD_BUG - break compile if used. - * - * If you have some code that you expect the compiler to eliminate at - * build time, you should use BUILD_BUG to detect if it is - * unexpectedly used. - */ -#define BUILD_BUG() \ - do { \ - extern void __build_bug_failed(void) \ - __linktime_error("BUILD_BUG failed"); \ - __build_bug_failed(); \ - } while (0) - -#endif /* __CHECKER__ */ - /* Trap pasters of __FUNCTION__ at compile-time */ #define __FUNCTION__ (__func__) -- cgit v1.2.3-70-g09d2 From 6c03438edeb5c359af35f060ea016ca65671c269 Mon Sep 17 00:00:00 2001 From: Paul Gortmaker Date: Wed, 23 Nov 2011 21:39:49 -0500 Subject: kernel.h: doesn't explicitly use bug.h, so don't include it. This header isn't using bug.h infrastructure, but due to historical reasons, it was including it. Removing it revealed several implicit dependencies (since kernel.h is everywhere) so we've fixed those 1st before deploying this change. Signed-off-by: Paul Gortmaker --- include/linux/kernel.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 5dba983b8d6..bef5480396d 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -20,7 +20,6 @@ #include #include #include -#include #define USHRT_MAX ((u16)(~0U)) #define SHRT_MAX ((s16)(USHRT_MAX>>1)) -- cgit v1.2.3-70-g09d2 From 6061d949dd984c762ee272a88e77699fa675d1c8 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Fri, 23 Mar 2012 15:02:16 -0700 Subject: include/ and checkpatch: prefer __scanf to __attribute__((format(scanf,...) It's equivalent to __printf, so prefer __scanf. Signed-off-by: Joe Perches Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/compiler-gcc.h | 3 ++- include/linux/kernel.h | 8 ++++---- include/xen/xenbus.h | 4 ++-- scripts/checkpatch.pl | 6 ++++++ 4 files changed, 14 insertions(+), 7 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 3fd17c24922..e5834aa24b9 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -87,7 +87,8 @@ */ #define __pure __attribute__((pure)) #define __aligned(x) __attribute__((aligned(x))) -#define __printf(a,b) __attribute__((format(printf,a,b))) +#define __printf(a, b) __attribute__((format(printf, a, b))) +#define __scanf(a, b) __attribute__((format(scanf, a, b))) #define noinline __attribute__((noinline)) #define __attribute_const__ __attribute__((__const__)) #define __maybe_unused __attribute__((unused)) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index d801acb5e68..f2085b541a2 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -328,10 +328,10 @@ extern __printf(2, 3) char *kasprintf(gfp_t gfp, const char *fmt, ...); extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args); -extern int sscanf(const char *, const char *, ...) - __attribute__ ((format (scanf, 2, 3))); -extern int vsscanf(const char *, const char *, va_list) - __attribute__ ((format (scanf, 2, 0))); +extern __scanf(2, 3) +int sscanf(const char *, const char *, ...); +extern __scanf(2, 0) +int vsscanf(const char *, const char *, va_list); extern int get_option(char **str, int *pint); extern char *get_options(const char *str, int nints, int *ints); diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h index e8c599b237c..0a7515c1e3a 100644 --- a/include/xen/xenbus.h +++ b/include/xen/xenbus.h @@ -139,9 +139,9 @@ int xenbus_transaction_start(struct xenbus_transaction *t); int xenbus_transaction_end(struct xenbus_transaction t, int abort); /* Single read and scanf: returns -errno or num scanned if > 0. */ +__scanf(4, 5) int xenbus_scanf(struct xenbus_transaction t, - const char *dir, const char *node, const char *fmt, ...) - __attribute__((format(scanf, 4, 5))); + const char *dir, const char *node, const char *fmt, ...); /* Single printf and write: returns -errno or 0. */ __printf(4, 5) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index a3b9782441f..89d24b3ea43 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -3123,6 +3123,12 @@ sub process { "__printf(string-index, first-to-check) is preferred over __attribute__((format(printf, string-index, first-to-check)))\n" . $herecurr); } +# Check for __attribute__ format(scanf, prefer __scanf + if ($line =~ /\b__attribute__\s*\(\s*\(\s*format\s*\(\s*scanf\b/) { + WARN("PREFER_SCANF", + "__scanf(string-index, first-to-check) is preferred over __attribute__((format(scanf, string-index, first-to-check)))\n" . $herecurr); + } + # check for sizeof(&) if ($line =~ /\bsizeof\s*\(\s*\&/) { WARN("SIZEOF_ADDRESS", -- cgit v1.2.3-70-g09d2 From 1ac101a5d675aca2426c5cd460c73fb95acb8391 Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Fri, 23 Mar 2012 15:02:54 -0700 Subject: procfs: add num_to_str() to speed up /proc/stat == stat_check.py num = 0 with open("/proc/stat") as f: while num < 1000 : data = f.read() f.seek(0, 0) num = num + 1 == perf shows 20.39% stat_check.py [kernel.kallsyms] [k] format_decode 13.41% stat_check.py [kernel.kallsyms] [k] number 12.61% stat_check.py [kernel.kallsyms] [k] vsnprintf 10.85% stat_check.py [kernel.kallsyms] [k] memcpy 4.85% stat_check.py [kernel.kallsyms] [k] radix_tree_lookup 4.43% stat_check.py [kernel.kallsyms] [k] seq_printf This patch removes most of calls to vsnprintf() by adding num_to_str() and seq_print_decimal_ull(), which prints decimal numbers without rich functions provided by printf(). On my 8cpu box. == Before patch == [root@bluextal test]# time ./stat_check.py real 0m0.150s user 0m0.026s sys 0m0.121s == After patch == [root@bluextal test]# time ./stat_check.py real 0m0.055s user 0m0.022s sys 0m0.030s [akpm@linux-foundation.org: remove incorrect comment, use less statck in num_to_str(), move comment from .h to .c, simplify seq_put_decimal_ull()] [andrea@betterlinux.com: avoid breaking the ABI in /proc/stat] Signed-off-by: KAMEZAWA Hiroyuki Signed-off-by: Andrea Righi Cc: Eric Dumazet Cc: Glauber Costa Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Paul Turner Cc: Russell King Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/stat.c | 55 ++++++++++++++++++++++++------------------------ fs/seq_file.c | 33 +++++++++++++++++++++++++++++ include/linux/kernel.h | 2 ++ include/linux/seq_file.h | 3 ++- lib/vsprintf.c | 20 ++++++++++++++++++ 5 files changed, 84 insertions(+), 29 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/fs/proc/stat.c b/fs/proc/stat.c index ac446114cd4..6a0c62d6e44 100644 --- a/fs/proc/stat.c +++ b/fs/proc/stat.c @@ -89,18 +89,19 @@ static int show_stat(struct seq_file *p, void *v) } sum += arch_irq_stat(); - seq_printf(p, "cpu %llu %llu %llu %llu %llu %llu %llu %llu %llu " - "%llu\n", - (unsigned long long)cputime64_to_clock_t(user), - (unsigned long long)cputime64_to_clock_t(nice), - (unsigned long long)cputime64_to_clock_t(system), - (unsigned long long)cputime64_to_clock_t(idle), - (unsigned long long)cputime64_to_clock_t(iowait), - (unsigned long long)cputime64_to_clock_t(irq), - (unsigned long long)cputime64_to_clock_t(softirq), - (unsigned long long)cputime64_to_clock_t(steal), - (unsigned long long)cputime64_to_clock_t(guest), - (unsigned long long)cputime64_to_clock_t(guest_nice)); + seq_puts(p, "cpu "); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(user)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(nice)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(system)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(idle)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(iowait)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(irq)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(softirq)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(steal)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(guest)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(guest_nice)); + seq_putc(p, '\n'); + for_each_online_cpu(i) { /* Copy values here to work around gcc-2.95.3, gcc-2.96 */ user = kcpustat_cpu(i).cpustat[CPUTIME_USER]; @@ -113,26 +114,24 @@ static int show_stat(struct seq_file *p, void *v) steal = kcpustat_cpu(i).cpustat[CPUTIME_STEAL]; guest = kcpustat_cpu(i).cpustat[CPUTIME_GUEST]; guest_nice = kcpustat_cpu(i).cpustat[CPUTIME_GUEST_NICE]; - seq_printf(p, - "cpu%d %llu %llu %llu %llu %llu %llu %llu %llu %llu " - "%llu\n", - i, - (unsigned long long)cputime64_to_clock_t(user), - (unsigned long long)cputime64_to_clock_t(nice), - (unsigned long long)cputime64_to_clock_t(system), - (unsigned long long)cputime64_to_clock_t(idle), - (unsigned long long)cputime64_to_clock_t(iowait), - (unsigned long long)cputime64_to_clock_t(irq), - (unsigned long long)cputime64_to_clock_t(softirq), - (unsigned long long)cputime64_to_clock_t(steal), - (unsigned long long)cputime64_to_clock_t(guest), - (unsigned long long)cputime64_to_clock_t(guest_nice)); + seq_printf(p, "cpu%d", i); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(user)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(nice)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(system)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(idle)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(iowait)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(irq)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(softirq)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(steal)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(guest)); + seq_put_decimal_ull(p, ' ', cputime64_to_clock_t(guest_nice)); + seq_putc(p, '\n'); } seq_printf(p, "intr %llu", (unsigned long long)sum); /* sum again ? it could be updated? */ for_each_irq_nr(j) - seq_printf(p, " %u", kstat_irqs(j)); + seq_put_decimal_ull(p, ' ', kstat_irqs(j)); seq_printf(p, "\nctxt %llu\n" @@ -149,7 +148,7 @@ static int show_stat(struct seq_file *p, void *v) seq_printf(p, "softirq %llu", (unsigned long long)sum_softirq); for (i = 0; i < NR_SOFTIRQS; i++) - seq_printf(p, " %u", per_softirq_sums[i]); + seq_put_decimal_ull(p, ' ', per_softirq_sums[i]); seq_putc(p, '\n'); return 0; diff --git a/fs/seq_file.c b/fs/seq_file.c index aa242dc9937..7d19816c4cc 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -644,6 +644,39 @@ int seq_puts(struct seq_file *m, const char *s) } EXPORT_SYMBOL(seq_puts); +/* + * A helper routine for putting decimal numbers without rich format of printf(). + * only 'unsigned long long' is supported. + * This routine will put one byte delimiter + number into seq_file. + * This routine is very quick when you show lots of numbers. + * In usual cases, it will be better to use seq_printf(). It's easier to read. + */ +int seq_put_decimal_ull(struct seq_file *m, char delimiter, + unsigned long long num) +{ + int len; + + if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */ + goto overflow; + + m->buf[m->count++] = delimiter; + + if (num < 10) { + m->buf[m->count++] = num + '0'; + return 0; + } + + len = num_to_str(m->buf + m->count, m->size - m->count, num); + if (!len) + goto overflow; + m->count += len; + return 0; +overflow: + m->count = m->size; + return -1; +} +EXPORT_SYMBOL(seq_put_decimal_ull); + /** * seq_write - write arbitrary data to buffer * @seq: seq_file identifying the buffer to which data should be written diff --git a/include/linux/kernel.h b/include/linux/kernel.h index f2085b541a2..3e140add536 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -312,6 +312,8 @@ extern long long simple_strtoll(const char *,char **,unsigned int); #define strict_strtoull kstrtoull #define strict_strtoll kstrtoll +extern int num_to_str(char *buf, int size, unsigned long long num); + /* lib/printf utilities */ extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...); diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h index 44f1514b00b..5bba42c9944 100644 --- a/include/linux/seq_file.h +++ b/include/linux/seq_file.h @@ -121,9 +121,10 @@ int single_release(struct inode *, struct file *); void *__seq_open_private(struct file *, const struct seq_operations *, int); int seq_open_private(struct file *, const struct seq_operations *, int); int seq_release_private(struct inode *, struct file *); +int seq_put_decimal_ull(struct seq_file *m, char delimiter, + unsigned long long num); #define SEQ_START_TOKEN ((void *)1) - /* * Helpers for iteration over list_head-s in seq_files */ diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 38e612e66da..385c40291cd 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -212,6 +212,26 @@ char *put_dec(char *buf, unsigned long long num) } } +/* + * Convert passed number to decimal string. + * Returns the length of string. On buffer overflow, returns 0. + * + * If speed is not important, use snprintf(). It's easy to read the code. + */ +int num_to_str(char *buf, int size, unsigned long long num) +{ + char tmp[21]; /* Enough for 2^64 in decimal */ + int idx, len; + + len = put_dec(tmp, num) - tmp; + + if (len > size) + return 0; + for (idx = 0; idx < len; ++idx) + buf[idx] = tmp[len - idx - 1]; + return len; +} + #define ZEROPAD 1 /* pad with zero */ #define SIGN 2 /* unsigned/signed long */ #define PLUS 4 /* show plus */ -- cgit v1.2.3-70-g09d2