From 8730662d7b2582f65dd6c59ab1e0b7fa461c79b0 Mon Sep 17 00:00:00 2001 From: Wei Wang Date: Tue, 24 Apr 2018 14:22:38 -0700 Subject: kernel.h: Fix a typo in comment Signed-off-by: Wei Wang Cc: Andrew Morton Cc: Borislav Petkov Cc: Crt Mori Cc: Josh Poimboeuf Cc: Kees Cook Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Randy Dunlap Cc: Steven Rostedt Cc: Thomas Gleixner Cc: gregkh@linuxfoundation.org Cc: wei.vince.wang@gmail.com Link: https://lkml.kernel.org/lkml/20180424212241.16013-1-wvw@google.com Signed-off-by: Ingo Molnar --- include/linux/kernel.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index d23123238534..941dc0a5a877 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -666,7 +666,7 @@ do { \ * your code. (Extra memory is used for special buffers that are * allocated when trace_printk() is used.) * - * A little optization trick is done here. If there's only one + * A little optimization trick is done here. If there's only one * argument, there's no need to scan the string for printf formats. * The trace_puts() will suffice. But how can we take advantage of * using trace_puts() when trace_printk() has only one argument? -- cgit v1.2.3 From cedc5b6aab493f6b1b1d381dccc0cc082da7d3d8 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 21 Aug 2018 21:55:28 -0700 Subject: kernel.h: documentation for roundup() vs round_up() Things like 3619dec5103d ("dh key: fix rounding up KDF output length") expose the lack of explicit documentation for roundup() vs round_up(). At least we can try to document it better if anyone goes looking. Link: http://lkml.kernel.org/r/20180703041950.GA43464@beast Signed-off-by: Kees Cook Cc: Ingo Molnar Cc: Greg Kroah-Hartman Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 941dc0a5a877..d6aac75b51ba 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -85,7 +85,23 @@ * arguments just once each. */ #define __round_mask(x, y) ((__typeof__(x))((y)-1)) +/** + * round_up - round up to next specified power of 2 + * @x: the value to round + * @y: multiple to round up to (must be a power of 2) + * + * Rounds @x up to next multiple of @y (which must be a power of 2). + * To perform arbitrary rounding up, use roundup() below. + */ #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) +/** + * round_down - round down to next specified power of 2 + * @x: the value to round + * @y: multiple to round down to (must be a power of 2) + * + * Rounds @x down to next multiple of @y (which must be a power of 2). + * To perform arbitrary rounding down, use rounddown() below. + */ #define round_down(x, y) ((x) & ~__round_mask(x, y)) /** @@ -110,13 +126,30 @@ # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d) #endif -/* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */ +/** + * roundup - round up to the next specified multiple + * @x: the value to up + * @y: multiple to round up to + * + * Rounds @x up to next multiple of @y. If @y will always be a power + * of 2, consider using the faster round_up(). + * + * The `const' here prevents gcc-3.3 from calling __divdi3 + */ #define roundup(x, y) ( \ { \ const typeof(y) __y = y; \ (((x) + (__y - 1)) / __y) * __y; \ } \ ) +/** + * rounddown - round down to next specified multiple + * @x: the value to round + * @y: multiple to round down to + * + * Rounds @x down to next multiple of @y. If @y will always be a power + * of 2, consider using the faster round_down(). + */ #define rounddown(x, y) ( \ { \ typeof(x) __x = (x); \ -- cgit v1.2.3