The rtc's status register allows to determine if a 32k crystal is
connected to keep the rtc running in low power states provided the
corresponding fuse bits were blown correctly during production.  (In case
they were not, the right frequency can be stated in the device tree.) If
there is no such crystal available force the 24 MHz XTAL clock to keep
running to retain the right date and time.  Otherwise use the crystal to
save some power.

It would be nice to only switch to the crystal when the XTAL clock is
about to be disabled and keep the crystal off when unneeded because XTAL
is always on while the chip is powered on.  But as sudden power loss isn't
detectable this is not save.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This commit does not change any logic here.  It just makes the code easier
to read.

This is how it looked like:
If err != 0 return err;
else return 0;
Signed-off-by: NRobert Kmiec <robert.r.kmiec@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It might be annoying to constantly see this:

	scripts/Makefile.kasan:16: Cannot use CONFIG_KASAN: -fsanitize=kernel-address is not supported by compiler

while performing allmodconfig/allyesconfig build tests.
Disable this warning if CONFIG_COMPILE_TEST=y.
Signed-off-by: NAndrey Ryabinin <a.ryabinin@samsung.com>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

sprintf() reliably returns the number of characters printed, so we don't
need to ask strlen() where we are.  Also replace calling sprintf("%02x")
in a loop with the much simpler bin2hex().

[akpm@linux-foundation.org: it's odd to include kernel.h after everything else]
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since commit 1f65f947 ("checkpatch: add checks for question mark and
colon spacing") back in 2008, checkpatch has reported false positive for
asm volatile uses of "::" checkpatch thinks colons should always have
spaces around it.

Add an exception for colons with colons on either side for this valid asm
volatile (and c++) use.
Signed-off-by: NJoe Perches <joe@perches.com>
Reported-by: NYehuda Yitschak <yehuday@marvell.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If a patch touches multiple files, the --fix and --fix-inplace option
doesn't keep the proper line count and makes the new patch file not able
to be applied via bad offset line numbers when lines are added or deleted
by the --fix option.

Dunno how that extra backslash snuck in there.
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ENOSYS is the mechanism used by user code to detect whether the running
kernel implements a given system call.  It should not be returned by
anything except an unimplemented system call.

Unfortunately, it is rather frequently used in the kernel to indicate that
various new functions of existing system calls are not implemented.  This
should be discouraged.

Improve the comment in errno.h to help clarify ENOSYS's purpose.
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ENOSYS means that a nonexistent system call was called.  We have a
bad habit of using it for things like invalid operations on
otherwise valid syscalls.  We should avoid this in new code.

Pervasive incorrect usage of ENOSYS came up at the kernel summit ABI
review discussion.  Let's see if checkpatch can help.

I'll submit a separate patch for include/uapi/asm-generic/errno.h.
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

const objects shouldn't be __read_mostly.  They are read-only.

Marking these objects as __read_mostly causes section conflicts with LTO
linking.

So add a test to try to avoid this issue.
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Code such as:
       x = timercmp(&now, &end, <);
Will currently trigger a checkpatch error. e.g.

ERROR: spaces required around that '<'

This is because the "Ignore operators passed as parameters" check looks
only for a comma following the operator.  Improve the check by also
looking for a close parenthesis.
Signed-off-by: NSam Bobroff <sam.bobroff@au1.ibm.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a test for sizeof(foo)/sizeof(foo[0]) that could be ARRAY_SIZE(foo).
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add another struct to the list of normally const struct types
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are #defines with long string constants like:
	#define foo "some really long string > 80 columns"
Add a long line exception for them.

Miscellanea:

Use the $String variable for slightly better readability
Signed-off-by: NJoe Perches <joe@perches.com>
Reported-by: NMadalin-Cristian Bucur <madalin.bucur@freescale.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit messages lines are sometimes overly long.

Suggest line wrapping at 75 columns so the default git commit log
indentation of 4 plus the commit message text still fits on an 80 column
screen.

Add a checkpatch test for long commit messages lines too.
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: David Miller <davem@davemloft.net>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently checkpatch warns when asm/file.h is included and linux/file.h
exists.  That conversion can be made when linux/file.h includes asm/file.h
which is not always the case.(See signal.h)
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: Andy Whitcroft <apw@canonical.com>
Acked-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Using 'const <type> const *' is generally meant to be written 'const
<type> * const'.

Add a test for the miswritten form.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a few conditions to the test to find
	return (ERRNO);

Make the output message a bit less cryptic too.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently checkpatch will fuss if one uses world writable settings in
debugfs files and DEVICE_ATTR uses by testing S_IWUGO but not testing
S_IWOTH, S_IRWXUGO or S_IALLUGO.

Extend the check to catch all cases exporting world writable permissions
including octal values.

[akpm@linux-foundation.org: remove stray $]
Signed-off-by: NJoe Perches <joe@perches.com>
Original-patch-by: NNicholas Mc Guire <hofrat@osadl.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If a codespell dictionary exists, use it if desired.  default is off,
maybe it could be turned on later.

codespell's dictionary format allows multiple possible corrections, ignore
that for now and only use the first suggestion.

Also add \b to spelling test so that consecutive misspelled words
are found properly.
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masanari Iida <standby24x7@gmail.com>
Cc: Lucas De Marchi <lucas.de.marchi@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

References: http://mid.gmane.org/1424977312-24902-1-git-send-email-ville.syrjala@linux.intel.comSigned-off-by: NJani Nikula <jani.nikula@intel.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Only commit log and patch additions are checked for typos and spelling
errors currently.  Add a check of the email subject line too.
Signed-off-by: NJoe Perches <joe@perches.com>
Suggested-by: NJani Nikula <jani.nikula@linux.intel.com>
Tested-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The "no space is necessary after a cast" sizeof exclusion doesn't work
properly.

The test reports a false positive for code like:

	BUILD_BUG_ON(sizeof(struct batadv_bla_claim_dst) != 6);

Make it work, simplify the exclusions, and add some comments.
Signed-off-by: NJoe Perches <joe@perches.com>
Reported-by: NMarek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 2473238e ("ihex: add support for CS:IP/EIP records") removes
the "default:" statement in the switch block, making the "return
usage();" line dead code and ihex2fw silently ignoring unknown options.
Restore this statement.

This bug was found by building with HOSTCC=clang and adding
-Wunreachable-code-return to HOSTCFLAGS.

Fixes: 2473238e ("ihex: add support for CS:IP/EIP records")
Signed-off-by: NNicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

bitmap_empty() has its own implementation.  But it's clearly as simple as:

	find_first_bit(src, nbits) == nbits

The same is true for 'bitmap_full'.
Signed-off-by: NYury Norov <yury.norov@gmail.com>
Cc: George Spelvin <linux@horizon.com>
Cc: Alexey Klimov <klimov.linux@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now that the kernel provides DIV_ROUND_CLOSEST_ULL(), drop the internal
implementation and use the kernel one.
Signed-off-by: NJavi Merino <javi.merino@arm.com>
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Cc: Peter Rosin <peda@axentia.se>
Acked-by: NMark Brown <broonie@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now that the kernel provides DIV_ROUND_CLOSEST_ULL(), drop the internal
implementation and use the kernel one.
Signed-off-by: NJavi Merino <javi.merino@arm.com>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: NAntti Palosaari <crope@iki.fi>
Reviewed-by: NAntti Palosaari <crope@iki.fi>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now that the kernel provides DIV_ROUND_CLOSEST_ULL(), drop the internal
implementation and use the kernel one.
Signed-off-by: NJavi Merino <javi.merino@arm.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now that the kernel provides DIV_ROUND_CLOSEST_ULL(), drop the internal
implementation and use the kernel one.
Signed-off-by: NJavi Merino <javi.merino@arm.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We have grown a number of different implementations of
DIV_ROUND_CLOSEST_ULL throughout the kernel.  Move the i915 one to
kernel.h so that it can be reused.
Signed-off-by: NJavi Merino <javi.merino@arm.com>
Reviewed-by: NJeff Epler <jepler@unpythonic.net>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Guenter Roeck <linux@roeck-us.net>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Alex Elder <elder@linaro.org>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Javi Merino <javi.merino@arm.com>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I hadn't had enough coffee when I wrote this. Currently, the final
increment of buf depends on the value loaded from the table, and
causes gcc to emit a cmov immediately before the return. It is smarter
to let it depend on r, since the increment can then be computed in
parallel with the final load/store pair. It also shaves 16 bytes of
.text.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace the loop iterating over pwm_freq_cksel0 with a call to
find_closest_descending().
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace RANGE_TO_REG() and FREQ_TO_REG() implementations with
calls to find_closest().
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use find_closest() to locate the closest average in ina226_avg_tab.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Describe proper naming convention for local variables in macros
resembling functions.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This series unduplicates the code used to find the member in an array
closest to 'x'.

The first patch adds a macro implementing the algorithm in two flavors -
for arrays sorted in ascending and descending order.  The second updates
Documentation/CodingStyle on the naming convention for local variables in
macros resembling functions.  Other three patches replace duplicated code
with calls to one of these macros in some hwmon drivers.

This patch (of 5):

Searching for the member of an array closest to 'x' is duplicated in
several places.

Add a new include - util_macros.h - and two macros that implement this
algorithm for arrays sorted both in ascending and descending order.

Uses linear search.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

bucket_find_contain() will search the bucket list for a dma_debug_entry.
When the entry isn't found it needs to search other buckets too, since
only the start address of a dma range is hashed (which might be in a
different bucket).

A copy of the dma_debug_entry is used to get the previous hash bucket
but when its list is searched the original dma_debug_entry is to be used
not its modified copy.

This fixes false "device driver tries to sync DMA memory it has not allocated"
warnings.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Horia Geanta <horia.geanta@freescale.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The most expensive part of decimal conversion is the divisions by 10
(albeit done using reciprocal multiplication with appropriately chosen
constants).  I decided to see if one could eliminate around half of
these multiplications by emitting two digits at a time, at the cost of a
200 byte lookup table, and it does indeed seem like there is something
to be gained, especially on 64 bits.  Microbenchmarking shows
improvements ranging from -50% (for numbers uniformly distributed in [0,
2^64-1]) to -25% (for numbers heavily biased toward the smaller end, a
more realistic distribution).

On a larger scale, perf shows that top, one of the big consumers of /proc
data, uses 0.5-1.0% fewer cpu cycles.

I had to jump through some hoops to get the 32 bit code to compile and run
on my 64 bit machine, so I'm not sure how relevant these numbers are, but
just for comparison the microbenchmark showed improvements between -30%
and -10%.

The bloat-o-meter costs are around 150 bytes (the generated code is a
little smaller, so it's not the full 200 bytes) on both 32 and 64 bit.
I'm aware that extra cache misses won't show up in a microbenchmark as
used above, but on the other hand decimal conversions often happen in bulk
(for example in the case of top).

I have of course tested that the new code generates the same output as the
old, for both the first and last 1e10 numbers in [0,2^64-1] and 4e9
'random' numbers in-between.

Test and verification code on github: https://github.com/Villemoes/dec.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Tested-by: NJeff Epler <jepler@unpythonic.net>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This file contains implementation for all find_*_bit{,_le}
So giving it more generic name looks reasonable.
Signed-off-by: NYury Norov <yury.norov@gmail.com>
Reviewed-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: NGeorge Spelvin <linux@horizon.com>
Cc: Alexey Klimov <klimov.linux@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Valentin Rothberg <valentinrothberg@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently all 'find_*_bit' family is located in lib/find_next_bit.c,
except 'find_last_bit', which is in lib/find_last_bit.c. It seems,
there's no major benefit to have it separated.
Signed-off-by: NYury Norov <yury.norov@gmail.com>
Reviewed-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: NGeorge Spelvin <linux@horizon.com>
Cc: Alexey Klimov <klimov.linux@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Valentin Rothberg <valentinrothberg@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patchset does rework to find_bit function family to achieve better
performance, and decrease size of text.  All rework is done in patch 1.
Patches 2 and 3 are about code moving and renaming.

It was boot-tested on x86_64 and MIPS (big-endian) machines.
Performance tests were ran on userspace with code like this:

	/* addr[] is filled from /dev/urandom */
	start = clock();
	while (ret < nbits)
		ret = find_next_bit(addr, nbits, ret + 1);

	end = clock();
	printf("%ld\t", (unsigned long) end - start);

On Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz measurements are: (for
find_next_bit, nbits is 8M, for find_first_bit - 80K)

	find_next_bit:		find_first_bit:
	new	current		new	current
	26932	43151		14777	14925
	26947	43182		14521	15423
	26507	43824		15053	14705
	27329	43759		14473	14777
	26895	43367		14847	15023
	26990	43693		15103	15163
	26775	43299		15067	15232
	27282	42752		14544	15121
	27504	43088		14644	14858
	26761	43856		14699	15193
	26692	43075		14781	14681
	27137	42969		14451	15061
	...			...

find_next_bit performance gain is 35-40%;
find_first_bit - no measurable difference.

On ARM machine, there is arch-specific implementation for find_bit.

Thanks a lot to George Spelvin and Rasmus Villemoes for hints and
helpful discussions.

This patch (of 3):

New implementations takes less space in source file (see diffstat) and in
object.  For me it's 710 vs 453 bytes of text.  It also shows better
performance.

find_last_bit description fixed due to obvious typo.

[akpm@linux-foundation.org: include linux/bitmap.h, per Rasmus]
Signed-off-by: NYury Norov <yury.norov@gmail.com>
Reviewed-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: NGeorge Spelvin <linux@horizon.com>
Cc: Alexey Klimov <klimov.linux@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Valentin Rothberg <valentinrothberg@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>