user/sven/linux.git/lib/bitmap.c, branch v4.14.130

lib: fix stall in __bitmap_parselist()

2018-04-19T06:56:20Z

commit 8351760ff5b2042039554b4948ddabaac644a976 upstream. 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 Signed-off-by: Greg Kroah-Hartman

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

bitmap: optimise bitmap_set and bitmap_clear of a single bit

2017-07-10T23:32:34Z

We have eight users calling bitmap_clear for a single bit and seventeen calling bitmap_set for a single bit. Rather than fix all of them to call __clear_bit or __set_bit, turn bitmap_clear and bitmap_set into inline functions and make this special case efficient. Link: http://lkml.kernel.org/r/20170628153221.11322-3-willy@infradead.org Signed-off-by: Matthew Wilcox Acked-by: Rasmus Villemoes Cc: Martin Schwidefsky Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel-api.rst: fix some complex tags at lib/bitmap.c

2017-04-02T20:29:33Z

Fix the following issues: ./lib/bitmap.c:869: WARNING: Definition list ends without a blank line; unexpected unindent. ./lib/bitmap.c:876: WARNING: Inline emphasis start-string without end-string. ./lib/bitmap.c:508: ERROR: Unexpected indentation. And make sure that a table and a footnote will use the right tags. Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Jonathan Corbet

lib/bitmap.c: enhance bitmap syntax

2016-10-11T22:06:30Z

Today there are platforms with many CPUs (up to 4K). Trying to boot only part of the CPUs may result in too long string. For example lets take NPS platform that is part of arch/arc. This platform have SMP system with 256 cores each with 16 HW threads (SMT machine) where HW thread appears as CPU to the kernel. In this example there is total of 4K CPUs. When one tries to boot only part of the HW threads from each core the string representing the map may be long... For example if for sake of performance we decided to boot only first half of HW threads of each core the map will look like: 0-7,16-23,32-39,...,4080-4087 This patch introduce new syntax to accommodate with such use case. I added an optional postfix to a range of CPUs which will choose according to given modulo the desired range of reminders i.e.: :sed_size/group_size For example, above map can be described in new syntax like this: 0-4095:8/16 Note that this patch is backward compatible with current syntax. [akpm@linux-foundation.org: rework documentation] Link: http://lkml.kernel.org/r/1473579629-4283-1-git-send-email-noamca@mellanox.com Signed-off-by: Noam Camus Cc: David Decotigny Cc: Ben Hutchings Cc: David S. Miller Cc: Pan Xinhui Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

x86/uaccess: Move thread_info::addr_limit to thread_struct

2016-07-15T08:26:30Z

struct thread_info is a legacy mess. To prepare for its partial removal, move thread_info::addr_limit out. As an added benefit, this way is simpler. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/15bee834d09402b47ac86f2feccdf6529f9bc5b0.1468527351.git.luto@kernel.org Signed-off-by: Ingo Molnar

lib/bitmap.c: conversion routines to/from u32 array

2016-02-20T03:54:09Z

Aimed at transferring bitmaps to/from user-space in a 32/64-bit agnostic way. Tested: unit tests (next patch) on qemu i386, x86_64, ppc, ppc64 BE and LE, ARM. Signed-off-by: David Decotigny Reviewed-by: Ben Hutchings Signed-off-by: David S. Miller

lib/bitmap.c: bitmap_parselist can accept string with whitespaces on head or tail

2015-09-10T20:29:01Z

In __bitmap_parselist we can accept whitespaces on head or tail during every parsing procedure. If input has valid ranges, there is no reason to reject the user. For example, bitmap_parselist(" 1-3, 5, ", &mask, nmaskbits). After separating the string, we get " 1-3", " 5", and " ". It's possible and reasonable to accept such string as long as the parsing result is correct. Signed-off-by: Pan Xinhui Cc: Yury Norov Cc: Chris Metcalf Cc: Rasmus Villemoes Cc: Sudeep Holla Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/bitmap.c: fix a special string handling bug in __bitmap_parselist

2015-09-10T20:29:01Z

If string end with '-', for exapmle, bitmap_parselist("1,0-",&mask, nmaskbits), It is not in a valid pattern, so add a check after loop. Return -EINVAL on such condition. Signed-off-by: Pan Xinhui Cc: Yury Norov Cc: Chris Metcalf Cc: Rasmus Villemoes Cc: Sudeep Holla Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/bitmap.c: correct a code style and do some, optimization

2015-09-10T20:29:01Z

We can avoid in-loop incrementation of ndigits. Save current totaldigits to ndigits before loop, and check ndigits against totaldigits after the loop. Signed-off-by: Pan Xinhui Cc: Yury Norov Cc: Chris Metcalf Cc: Rasmus Villemoes Cc: Sudeep Holla Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds