From c8bf1336824ebd698d37b71763e1c43190f2229a Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Fri, 10 Sep 2010 20:07:38 +0200 Subject: Consolidate min_not_zero We have several users of min_not_zero, each of them using their own definition. Move the define to kernel.h. Signed-off-by: Martin K. Petersen Signed-off-by: Jens Axboe --- include/linux/kernel.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2b0a35e6bc69..f5df2f4acb0d 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -640,6 +640,16 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } (void) (&_max1 == &_max2); \ _max1 > _max2 ? _max1 : _max2; }) +/** + * min_not_zero - return the minimum that is _not_ zero, unless both are zero + * @x: value1 + * @y: value2 + */ +#define min_not_zero(x, y) ({ \ + typeof(x) __x = (x); \ + typeof(y) __y = (y); \ + __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); }) + /** * clamp - return a value clamped to a given range with strict typechecking * @val: current value -- cgit v1.2.3 From f27c85c56b32c42bcc54a43189c1e00fdceb23ec Mon Sep 17 00:00:00 2001 From: Hagen Paul Pfeifer Date: Tue, 26 Oct 2010 14:22:21 -0700 Subject: kernel.h: add {min,max}3 macros Introduce two additional min/max macros to compare three operands. This will save some cycles as well as some bytes on the stack and last but not least more pleasing as macro nesting. [akpm@linux-foundation.org: fix warnings] Signed-off-by: Hagen Paul Pfeifer Cc: Joe Perches Cc: Ingo Molnar Cc: Hartley Sweeten Cc: Russell King Cc: Benjamin Herrenschmidt Cc: Thomas Gleixner Cc: Herbert Xu Cc: Roland Dreier Cc: Sean Hefty Cc: Pekka Enberg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index edef168a0406..8e786a27cfe6 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -651,6 +651,24 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } (void) (&_max1 == &_max2); \ _max1 > _max2 ? _max1 : _max2; }) +#define min3(x, y, z) ({ \ + typeof(x) _min1 = (x); \ + typeof(y) _min2 = (y); \ + typeof(z) _min3 = (z); \ + (void) (&_min1 == &_min2); \ + (void) (&_min1 == &_min3); \ + _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \ + (_min2 < _min3 ? _min2 : _min3); }) + +#define max3(x, y, z) ({ \ + typeof(x) _max1 = (x); \ + typeof(y) _max2 = (y); \ + typeof(z) _max3 = (z); \ + (void) (&_max1 == &_max2); \ + (void) (&_max1 == &_max3); \ + _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \ + (_max2 > _max3 ? _max2 : _max3); }) + /** * min_not_zero - return the minimum that is _not_ zero, unless both are zero * @x: value1 -- cgit v1.2.3 From a55621f15bc61826969a29e111ba131a55ef45de Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 26 Oct 2010 14:22:25 -0700 Subject: include/linux/kernel.h: add __must_check to strict_strto*() The whole point to using the strict functions is to check the return value. If you don't, strict_strto*() will return you uninitialised garbage. Offenders have been observed in the wild. Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 8e786a27cfe6..e9b492b33032 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -203,10 +203,10 @@ extern unsigned long simple_strtoul(const char *,char **,unsigned int); extern long simple_strtol(const char *,char **,unsigned int); extern unsigned long long simple_strtoull(const char *,char **,unsigned int); extern long long simple_strtoll(const char *,char **,unsigned int); -extern int strict_strtoul(const char *, unsigned int, unsigned long *); -extern int strict_strtol(const char *, unsigned int, long *); -extern int strict_strtoull(const char *, unsigned int, unsigned long long *); -extern int strict_strtoll(const char *, unsigned int, long long *); +extern int __must_check strict_strtoul(const char *, unsigned int, unsigned long *); +extern int __must_check strict_strtol(const char *, unsigned int, long *); +extern int __must_check strict_strtoull(const char *, unsigned int, unsigned long long *); +extern int __must_check strict_strtoll(const char *, unsigned int, long long *); extern int sprintf(char * buf, const char * fmt, ...) __attribute__ ((format (printf, 2, 3))); extern int vsprintf(char *buf, const char *, va_list) -- cgit v1.2.3 From 77006a0a828249dd69341f960043ee41e7487aa0 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 26 Oct 2010 14:22:49 -0700 Subject: ratelimit: add comment warning people off printk_ratelimit() printk_ratelimit() was a bad idea - we don't want subsytem A causing ratelimiting of subsystem B's messages. Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index e9b492b33032..77b04ed037df 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -277,6 +277,11 @@ asmlinkage int vprintk(const char *fmt, va_list args) asmlinkage int printk(const char * fmt, ...) __attribute__ ((format (printf, 1, 2))) __cold; +/* + * Please don't use printk_ratelimit(), because it shares ratelimiting state + * with all other unrelated printk_ratelimit() callsites. Instead use + * printk_ratelimited() or plain old __ratelimit(). + */ extern int __printk_ratelimit(const char *func); #define printk_ratelimit() __printk_ratelimit(__func__) extern bool printk_timed_ratelimit(unsigned long *caller_jiffies, -- cgit v1.2.3 From 658716d19f8f155c67d4677ba68034b8e492dfbe Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Tue, 26 Oct 2010 14:23:10 -0700 Subject: div64_u64(): improve precision on 32bit platforms The current implementation of div64_u64 for 32bit systems returns an approximately correct result when the divisor exceeds 32bits. Since doing 64bit division using 32bit hardware is a long since solved problem we just use one of the existing proven methods. Additionally, add a div64_s64 function to correctly handle doing signed 64bit division. Addresses https://bugzilla.redhat.com/show_bug.cgi?id=616105 Signed-off-by: Brian Behlendorf Signed-off-by: Oleg Nesterov Cc: Ben Woodard Cc: Jeremy Fitzhardinge Cc: Mark Grondona Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 5 +++++ include/linux/math64.h | 12 ++++++++++++ lib/div64.c | 52 ++++++++++++++++++++++++++++++++++++++++---------- 3 files changed, 59 insertions(+), 10 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 77b04ed037df..450092c1e35f 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -173,6 +173,11 @@ extern int _cond_resched(void); (__x < 0) ? -__x : __x; \ }) +#define abs64(x) ({ \ + s64 __x = (x); \ + (__x < 0) ? -__x : __x; \ + }) + #ifdef CONFIG_PROVE_LOCKING void might_fault(void); #else diff --git a/include/linux/math64.h b/include/linux/math64.h index c87f1528703a..23fcdfcba81b 100644 --- a/include/linux/math64.h +++ b/include/linux/math64.h @@ -35,6 +35,14 @@ static inline u64 div64_u64(u64 dividend, u64 divisor) return dividend / divisor; } +/** + * div64_s64 - signed 64bit divide with 64bit divisor + */ +static inline s64 div64_s64(s64 dividend, s64 divisor) +{ + return dividend / divisor; +} + #elif BITS_PER_LONG == 32 #ifndef div_u64_rem @@ -53,6 +61,10 @@ extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder); extern u64 div64_u64(u64 dividend, u64 divisor); #endif +#ifndef div64_s64 +extern s64 div64_s64(s64 dividend, s64 divisor); +#endif + #endif /* BITS_PER_LONG */ /** diff --git a/lib/div64.c b/lib/div64.c index a111eb8de9cf..5b4919191778 100644 --- a/lib/div64.c +++ b/lib/div64.c @@ -77,26 +77,58 @@ s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder) EXPORT_SYMBOL(div_s64_rem); #endif -/* 64bit divisor, dividend and result. dynamic precision */ +/** + * div64_u64 - unsigned 64bit divide with 64bit divisor + * @dividend: 64bit dividend + * @divisor: 64bit divisor + * + * This implementation is a modified version of the algorithm proposed + * by the book 'Hacker's Delight'. The original source and full proof + * can be found here and is available for use without restriction. + * + * 'http://www.hackersdelight.org/HDcode/newCode/divDouble.c' + */ #ifndef div64_u64 u64 div64_u64(u64 dividend, u64 divisor) { - u32 high, d; + u32 high = divisor >> 32; + u64 quot; - high = divisor >> 32; - if (high) { - unsigned int shift = fls(high); + if (high == 0) { + quot = div_u64(dividend, divisor); + } else { + int n = 1 + fls(high); + quot = div_u64(dividend >> n, divisor >> n); - d = divisor >> shift; - dividend >>= shift; - } else - d = divisor; + if (quot != 0) + quot--; + if ((dividend - quot * divisor) >= divisor) + quot++; + } - return div_u64(dividend, d); + return quot; } EXPORT_SYMBOL(div64_u64); #endif +/** + * div64_s64 - signed 64bit divide with 64bit divisor + * @dividend: 64bit dividend + * @divisor: 64bit divisor + */ +#ifndef div64_s64 +s64 div64_s64(s64 dividend, s64 divisor) +{ + s64 quot, t; + + quot = div64_u64(abs64(dividend), abs64(divisor)); + t = (dividend ^ divisor) >> 63; + + return (quot ^ t) - t; +} +EXPORT_SYMBOL(div64_s64); +#endif + #endif /* BITS_PER_LONG == 32 */ /* -- cgit v1.2.3