user/sven/linux.git/lib/bitmap.c, branch v4.19.127

lib/bitmap.c: fix remaining space computation in bitmap_print_to_pagebuf

2019-12-01T08:17:08Z

[ Upstream commit ce1091d471107dbf6f91db66a480a25950c9b9ff ] For various alignments of buf, the current expression computes 4096 ok 4095 ok 8190 8189 ... 4097 i.e., if the caller has already written two bytes into the page buffer, len is 8190 rather than 4094, because PTR_ALIGN aligns up to the next boundary. So if the printed version of the bitmap is huge, scnprintf() ends up writing beyond the page boundary. I don't think any current callers actually write anything before bitmap_print_to_pagebuf, but the API seems to be designed to allow it. [akpm@linux-foundation.org: use offset_in_page(), per Andy] [akpm@linux-foundation.org: include mm.h for offset_in_page()] Link: http://lkml.kernel.org/r/20180818131623.8755-7-linux@rasmusvillemoes.dk Signed-off-by: Rasmus Villemoes Reviewed-by: Andy Shevchenko Cc: Yury Norov Cc: Rasmus Villemoes Cc: Sudeep Holla Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

lib/bitmap.c: drop unnecessary 0 check for u32 array operations

2018-08-22T17:52:48Z

nbits == 0 is safe to be supplied to the function body, so remove unnecessary checks in bitmap_to_arr32() and bitmap_from_arr32(). Link: http://lkml.kernel.org/r/20180531131914.44352-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Acked-by: Yury Norov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

2018-08-18T23:48:07Z

Pull input updates from Dmitry Torokhov: - a new driver for Rohm BU21029 touch controller - new bitmap APIs: bitmap_alloc, bitmap_zalloc and bitmap_free - updates to Atmel, eeti. pxrc and iforce drivers - assorted driver cleanups and fixes. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (57 commits) MAINTAINERS: Add PhoenixRC Flight Controller Adapter Input: do not use WARN() in input_alloc_absinfo() Input: mark expected switch fall-throughs Input: raydium_i2c_ts - use true and false for boolean values Input: evdev - switch to bitmap API Input: gpio-keys - switch to bitmap_zalloc() Input: elan_i2c_smbus - cast sizeof to int for comparison bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap_free() md: Avoid namespace collision with bitmap API dm: Avoid namespace collision with bitmap API Input: pm8941-pwrkey - add resin entry Input: pm8941-pwrkey - abstract register offsets and event code Input: iforce - reorganize joystick configuration lists Input: atmel_mxt_ts - move completion to after config crc is updated Input: atmel_mxt_ts - don't report zero pressure from T9 Input: atmel_mxt_ts - zero terminate config firmware file Input: atmel_mxt_ts - refactor config update code to add context struct Input: atmel_mxt_ts - config CRC may start at T71 Input: atmel_mxt_ts - remove unnecessary debug on ENOMEM Input: atmel_mxt_ts - remove duplicate setup of ABS_MT_PRESSURE ...

bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap_free()

2018-08-01T22:49:40Z

A lot of code become ugly because of open coding allocations for bitmaps. Introduce three helpers to allow users be more clear of intention and keep their code neat. Note, due to multiple circular dependencies we may not provide the helpers as inliners. For now we keep them exported and, perhaps, at some point in the future we will sort out header inclusion and inheritance. Signed-off-by: Andy Shevchenko Signed-off-by: Dmitry Torokhov

lib/bitmap.c: micro-optimization for __bitmap_complement()

2018-06-08T00:34:39Z

Use BITS_TO_LONGS() macro to avoid calculation of reminder (bits % BITS_PER_LONG) On ARM64 it saves 5 instruction for function - 16 before and 11 after. Link: http://lkml.kernel.org/r/20180411145914.6011-1-ynorov@caviumnetworks.com Signed-off-by: Yury Norov Reviewed-by: Andrew Morton Cc: Matthew Wilcox Cc: Rasmus Villemoes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib: fix stall in __bitmap_parselist()

2018-04-06T04:36:21Z

syzbot is catching stalls at __bitmap_parselist() (https://syzkaller.appspot.com/bug?id=ad7e0351fbc90535558514a71cd3edc11681997a). The trigger is unsigned long v = 0; bitmap_parselist("7:,", &v, BITS_PER_LONG); which results in hitting infinite loop at while (a <= b) { off = min(b - a + 1, used_size); bitmap_set(maskp, a, off); a += group_size; } due to used_size == group_size == 0. Link: http://lkml.kernel.org/r/20180404162647.15763-1-ynorov@caviumnetworks.com Fixes: 0a5ce0831d04382a ("lib/bitmap.c: make bitmap_parselist() thread-safe and much faster") Signed-off-by: Yury Norov Reported-by: Tetsuo Handa Reported-by: syzbot Cc: Noam Camus Cc: Rasmus Villemoes Cc: Matthew Wilcox Cc: Mauro Carvalho Chehab Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

bitmap: replace bitmap_{from,to}_u32array

2018-02-07T02:32:44Z

with bitmap_{from,to}_arr32 over the kernel. Additionally to it: * __check_eq_bitmap() now takes single nbits argument. * __check_eq_u32_array is not used in new test but may be used in future. So I don't remove it here, but annotate as __used. Tested on arm64 and 32-bit BE mips. [arnd@arndb.de: perf: arm_dsu_pmu: convert to bitmap_from_arr32] Link: http://lkml.kernel.org/r/20180201172508.5739-2-ynorov@caviumnetworks.com [ynorov@caviumnetworks.com: fix net/core/ethtool.c] Link: http://lkml.kernel.org/r/20180205071747.4ekxtsbgxkj5b2fz@yury-thinkpad Link: http://lkml.kernel.org/r/20171228150019.27953-2-ynorov@caviumnetworks.com Signed-off-by: Yury Norov Signed-off-by: Arnd Bergmann Cc: Ben Hutchings Cc: David Decotigny , Cc: David S. Miller , Cc: Geert Uytterhoeven Cc: Matthew Wilcox Cc: Rasmus Villemoes Cc: Heiner Kallweit Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

bitmap: new bitmap_copy_safe and bitmap_{from,to}_arr32

2018-02-07T02:32:44Z

This patchset replaces bitmap_{to,from}_u32array with more simple and standard looking copy-like functions. bitmap_from_u32array() takes 4 arguments (bitmap_to_u32array is similar): - unsigned long *bitmap, which is destination; - unsigned int nbits, the length of destination bitmap, in bits; - const u32 *buf, the source; and - unsigned int nwords, the length of source buffer in ints. In description to the function it is detailed like: * copy min(nbits, 32*nwords) bits from @buf to @bitmap, remaining * bits between nword and nbits in @bitmap (if any) are cleared. Having two size arguments looks unneeded and potentially dangerous. It is unneeded because normally user of copy-like function should take care of the size of destination and make it big enough to fit source data. And it is dangerous because function may hide possible error if user doesn't provide big enough bitmap, and data becomes silently dropped. That's why all copy-like functions have 1 argument for size of copying data, and I don't see any reason to make bitmap_from_u32array() different. One exception that comes in mind is strncpy() which also provides size of destination in arguments, but it's strongly argued by the possibility of taking broken strings in source. This is not the case of bitmap_{from,to}_u32array(). There is no many real users of bitmap_{from,to}_u32array(), and they all very clearly provide size of destination matched with the size of source, so additional functionality is not used in fact. Like this: bitmap_from_u32array(to->link_modes.supported, __ETHTOOL_LINK_MODE_MASK_NBITS, link_usettings.link_modes.supported, __ETHTOOL_LINK_MODE_MASK_NU32); Where: #define __ETHTOOL_LINK_MODE_MASK_NU32 \ DIV_ROUND_UP(__ETHTOOL_LINK_MODE_MASK_NBITS, 32) In this patch, bitmap_copy_safe and bitmap_{from,to}_arr32 are introduced. 'Safe' in bitmap_copy_safe() stands for clearing unused bits in bitmap beyond last bit till the end of last word. It is useful for hardening API when bitmap is assumed to be exposed to userspace. bitmap_{from,to}_arr32 functions are replacements for bitmap_{from,to}_u32array. They don't take unneeded nwords argument, and so simpler in implementation and understanding. This patch suggests optimization for 32-bit systems - aliasing bitmap_{from,to}_arr32 to bitmap_copy_safe. Other possible optimization is aliasing 64-bit LE bitmap_{from,to}_arr32 to more generic function(s). But I didn't end up with the function that would be helpful by itself, and can be used to alias 64-bit LE bitmap_{from,to}_arr32, like bitmap_copy_safe() does. So I preferred to leave things as is. The following patch switches kernel to new API and introduces test for it. Discussion is here: https://lkml.org/lkml/2017/11/15/592 [ynorov@caviumnetworks.com: rename bitmap_copy_safe to bitmap_copy_clear_tail] Link: http://lkml.kernel.org/r/20180201172508.5739-3-ynorov@caviumnetworks.com Link: http://lkml.kernel.org/r/20171228150019.27953-1-ynorov@caviumnetworks.com Signed-off-by: Yury Norov Cc: Ben Hutchings Cc: David Decotigny , Cc: David S. Miller , Cc: Geert Uytterhoeven Cc: Matthew Wilcox Cc: Rasmus Villemoes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

documentation: kernel-api: add more info on bitmap functions

2017-10-19T19:01:40Z

There are some good comments about bitmap operations in lib/bitmap.c and include/linux/bitmap.h, so format them for document generation and pull them into core-api/kernel-api.rst. I converted the "tables" of functions from using tabs to using spaces so that they are more readable in the source file and in the generated output. Signed-off-by: Randy Dunlap Signed-off-by: Jonathan Corbet

lib/bitmap.c: make bitmap_parselist() thread-safe and much faster

2017-09-09T01:26:49Z

Current implementation of bitmap_parselist() uses a static variable to save local state while setting bits in the bitmap. It is obviously wrong if we assume execution in multiprocessor environment. Fortunately, it's possible to rewrite this portion of code to avoid using the static variable. It is also possible to set bits in the mask per-range with bitmap_set(), not per-bit, as it is implemented now, with set_bit(); which is way faster. The important side effect of this change is that setting bits in this function from now is not per-bit atomic and less memory-ordered. This is because set_bit() guarantees the order of memory accesses, while bitmap_set() does not. I think that it is the advantage of the new approach, because the bitmap_parselist() is intended to initialise bit arrays, and user should protect the whole bitmap during initialisation if needed. So protecting individual bits looks expensive and useless. Also, other range-oriented functions in lib/bitmap.c don't worry much about atomicity. With all that, setting 2k bits in map with the pattern like 0-2047:128/256 becomes ~50 times faster after applying the patch in my testing environment (arm64 hosted on qemu). The second patch of the series adds the test for bitmap_parselist(). It's not intended to cover all tricky cases, just to make sure that I didn't screw up during rework. Link: http://lkml.kernel.org/r/20170807225438.16161-1-ynorov@caviumnetworks.com Signed-off-by: Yury Norov Cc: Noam Camus Cc: Rasmus Villemoes Cc: Matthew Wilcox Cc: Mauro Carvalho Chehab Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds