The new bitmap function bitmap_cut() copies bits from source to
destination by removing the region specified by parameters first
and cut, and remapping the bits above the cut region by right
shifting them.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The IPI code of x86 needs to evaluate whether the target cpumask is equal
to the cpu_online_mask or equal except for the calling CPU.
To replace the current implementation which requires the usage of a
temporary cpumask, which might involve allocations, add a new function
which compares a cpumask to the result of two other cpumasks which are
or'ed together before comparison.
This allows to make the required decision in one go and the calling code
then can check for the calling CPU being set in the target mask with
cpumask_test_cpu().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190722105220.585449120@linutronix.de
Patch series "lib: rework bitmap_parselist and tests", v5.
bitmap_parselist has been evolved from a pretty simple idea for long and
now lacks for refactoring. It is not structured, has nested loops and a
set of opaque-named variables.
Things are more complicated because bitmap_parselist() is a part of user
interface, and its behavior should not change.
In this patchset
- bitmap_parselist_user() made a wrapper on bitmap_parselist();
- bitmap_parselist() reworked (patch 2);
- time measurement in test_bitmap_parselist switched to ktime_get
(patch 3);
- new tests introduced (patch 4), and
- bitmap_parselist_user() testing enabled with the same testset as
bitmap_parselist() (patch 5).
This patch (of 5):
Currently we parse user data byte after byte which leads to
overcomplification of parsing algorithm. The only user of
bitmap_parselist_user() is not performance-critical, and so we can
duplicate user data to kernel buffer and simply call bitmap_parselist().
This rework lets us unify and simplify bitmap_parselist() and
bitmap_parselist_user(), which is done in the following patch.
Link: http://lkml.kernel.org/r/20190405173211.11373-2-ynorov@marvell.com
Signed-off-by: Yury Norov <ynorov@marvell.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Mike Travis <travis@sgi.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The bitmap_remap, _bitremap, _onto and _fold functions are only used,
via their node_ wrappers, in mm/mempolicy.c, which is only built for
CONFIG_NUMA. The helper bitmap_ord_to_pos used by these functions is
global, but its only external caller is node_random() in lib/nodemask.c,
which is also guarded by CONFIG_NUMA.
For !CONFIG_NUMA:
add/remove: 0/6 grow/shrink: 0/0 up/down: 0/-621 (-621)
Function old new delta
bitmap_pos_to_ord 20 - -20
bitmap_ord_to_pos 70 - -70
bitmap_bitremap 81 - -81
bitmap_fold 113 - -113
bitmap_onto 123 - -123
bitmap_remap 214 - -214
Total: Before=4776, After=4155, chg -13.00%
Link: http://lkml.kernel.org/r/20190329205353.6010-2-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <linux@rasmusvillemoes.dk>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Yury Norov <ynorov@caviumnetworks.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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
...
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 <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
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 <ynorov@caviumnetworks.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: David Decotigny <decot@googlers.com>,
Cc: David S. Miller <davem@davemloft.net>,
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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 <ynorov@caviumnetworks.com>
Cc: Noam Camus <noamca@mellanox.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
