This macro is only used by net/ipv6/mcast.c, but there is no reason
why it must be BUILD_BUG_ON_NULL().

Replace it with BUILD_BUG_ON_ZERO(), and remove BUILD_BUG_ON_NULL()
definition from <linux/build_bug.h>.

Link: http://lkml.kernel.org/r/1515121833-3174-3-git-send-email-yamada.masahiro@socionext.comSigned-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Do not duplicate BUILD_BUG_ON*.  Use ones from <linux/build_bug.h>.

Link: http://lkml.kernel.org/r/1515121833-3174-2-git-send-email-yamada.masahiro@socionext.comSigned-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently KCOV_ENABLE does not check if the current task is already
associated with another kcov descriptor.  As the result it is possible
to associate a single task with more than one kcov descriptor, which
later leads to a memory leak of the old descriptor.  This relation is
really meant to be one-to-one (task has only one back link).

Extend validation to detect such misuse.

Link: http://lkml.kernel.org/r/20180122082520.15716-1-dvyukov@google.com
Fixes: 5c9a8750 ("kernel: add kcov code coverage")
Signed-off-by: NDmitry Vyukov <dvyukov@google.com>
Reported-by: NShankara Pailoor <sp3485@columbia.edu>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: syzbot <syzkaller@googlegroups.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This reverts commit ba62bafe ("kernel/relay.c: fix potential memory leak").

This commit introduced a double free bug, because 'chan' is already
freed by the line:

    kref_put(&chan->kref, relay_destroy_channel);

This bug was found by syzkaller, using the BLKTRACESETUP ioctl.

Link: http://lkml.kernel.org/r/20180127004759.101823-1-ebiggers3@gmail.com
Fixes: ba62bafe ("kernel/relay.c: fix potential memory leak")
Signed-off-by: NEric Biggers <ebiggers@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org>	[4.7+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

getnstimeofday() is deprecated, so I'm converting this to use
ktime_get_real_ts64() as a safe replacement.  I considered using
ktime_get_real() instead, but since the algorithm here depends on the
exact timing, I decided to introduce fewer changes and leave the code
that determines the nanoseconds since the last seconds wrap untouched.

It's not entirely clear to me whether we should also change the time
base to CLOCK_BOOTTIME or CLOCK_TAI.  With boottime, we would be
independent of changes due to settimeofday() and only see the speed
adjustment from the upstream clock source, with the downside of having
the signal be at an arbirary offset from the start of the UTC second
signal.  With CLOCK_TAI, we would use the same offset from the UTC
second as before and still suffer from settimeofday() adjustments, but
would be less confused during leap seconds.

Both boottime and tai only offer usable (i.e.  avoiding ktime_t to
timespec64 conversion) interfaces for ktime_t though, so either way,
changing it wouldn't take significantly more work.  CLOCK_MONOTONIC
could be used with ktime_get_ts64(), but would lose synchronization
across a suspend/resume cycle, which seems worse.

Link: http://lkml.kernel.org/r/20180116171451.3095620-1-arnd@arndb.deSigned-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NRodolfo Giometti <giometti@enneenne.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are several functions that do find_task_by_vpid() followed by
get_task_struct().  We can use a helper function instead.

Link: http://lkml.kernel.org/r/1509602027-11337-1-git-send-email-rppt@linux.vnet.ibm.comSigned-off-by: NMike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

checkpatch pointed out the following:

  Comparison to NULL could be written !...

Thus fix the affected source code places.

Link: http://lkml.kernel.org/r/c3e79a1a-891e-cb62-990f-bd99839311b9@users.sourceforge.netSigned-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/rapidio/devices/tsi721_dma.c: delete an unnecessary variable initialisation in tsi721_alloc_chan_resources()

The local variable "desc" will eventually be set to an appropriate pointer
a bit later. Thus omit the explicit initialisation at the beginning.

Link: http://lkml.kernel.org/r/728d8e20-4ae9-d661-d932-2d99ce67e71f@users.sourceforge.netSigned-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/rapidio/devices/tsi721_dma.c: delete an error message for a failed memory allocation in tsi721_alloc_chan_resources()

Omit an extra message for a memory allocation failure in this function.

This issue was detected by using the Coccinelle software.

Link: http://lkml.kernel.org/r/a96fcaf8-ea24-bcac-0214-273620349d42@users.sourceforge.netSigned-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

checkpatch pointed information out like the following.

  WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable

Thus fix the affected source code places.

Link: http://lkml.kernel.org/r/5f51f606-ece8-7bff-bb86-81d182c49b98@users.sourceforge.netSigned-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* Return an error code without storing it in an intermediate variable.

* Delete the label "out" and local variable "rc" which became unnecessary
  with this refactoring.

Link: http://lkml.kernel.org/r/8db441e1-c227-64e7-4747-095da63d7a2e@users.sourceforge.netSigned-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The local variable "rc" will be set to an appropriate value a bit later.
Thus omit the explicit initialisation at the beginning.

Link: http://lkml.kernel.org/r/ed729e8c-815c-8b56-a48f-1be579d0cc2b@users.sourceforge.netSigned-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace the specification of data structures by pointer dereferences as
the parameter for the operator "sizeof" to make the corresponding size
determination a bit safer according to the Linux coding style
convention.

This issue was detected by using the Coccinelle software.

Link: http://lkml.kernel.org/r/495f571c-fb4d-b1d5-a6e5-494f2c537a8d@users.sourceforge.netSigned-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

checkpatch pointed information out like the following.

  ERROR: do not use assignment in if condition

Thus fix the affected source code places.

Link: http://lkml.kernel.org/r/6f5631ed-ec3e-503d-850a-ab09b5736dbe@users.sourceforge.netSigned-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

checkpatch pointed information out like the following.

  Comparison to NULL could be written ...

Thus fix the affected source code places.

Link: http://lkml.kernel.org/r/739f9f1c-3ebe-c21b-c5e2-31976cfbc0ee@users.sourceforge.netSigned-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "RapidIO: Adjustments for some function implementations".

This patch (of 7):

Omit an extra message for a memory allocation failure in this function.

This issue was detected by using the Coccinelle software.

Link: http://lkml.kernel.org/r/dfd6887b-2521-cbf2-af5b-e70b5fa4c33c@users.sourceforge.netSigned-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

CPUmasks are never big enough to warrant 64-bit code.

Space savings:

	add/remove: 0/0 grow/shrink: 1/4 up/down: 3/-17 (-14)
	Function                                     old     new   delta
	sched_init_numa                             1530    1533      +3
	compat_sys_sched_setaffinity                 160     159      -1
	sys_sched_getaffinity                        197     195      -2
	sys_sched_setaffinity                        183     176      -7
	compat_sys_sched_getaffinity                 179     172      -7

Link: http://lkml.kernel.org/r/20171204165531.GA8221@avx2Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
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>

All other places that deals with namespaces have an explanation of why
the restriction is there.

The description added in this commit was based on commit e66eded8
("userns: Don't allow CLONE_NEWUSER | CLONE_FS").

Link: http://lkml.kernel.org/r/20171112151637.13258-1-marcos.souza.org@gmail.comSigned-off-by: NMarcos Paulo de Souza <marcos.souza.org@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Thus reducing one indentation level while maintaining the same rationale.

Link: http://lkml.kernel.org/r/20171117002929.5155-1-marcos.souza.org@gmail.comSigned-off-by: NMarcos Paulo de Souza <marcos.souza.org@gmail.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix grammar and add an omitted word.

Link: http://lkml.kernel.org/r/1a5a021c-0207-f793-7f07-addca26772d5@infradead.org
Fixes: f9886bc5 ("signal: Document the strange si_codes used by ptrace event stops")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When creating a file inside a directory that has the setgid flag set, give
the new file the group ID of the parent, and also the setgid flag if it is
a directory itself.

Link: http://lkml.kernel.org/r/20171204192705.GA6101@debian.homeSigned-off-by: NErnesto A. Fernandez <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: NVyacheslav Dubeyko <slava@dubeyko.com>
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>

The superblock and segment timestamps are used only internally in nilfs2
and can be read out using sysfs.

Since we are using the old 'get_seconds()' interface and store the data
as timestamps, the behavior differs slightly between 64-bit and 32-bit
kernels, the latter will show incorrect timestamps after 2038 in sysfs,
and presumably fail completely in 2106 as comparisons go wrong.

This changes nilfs2 to use time64_t with ktime_get_real_seconds() to
handle timestamps, making the behavior consistent and correct on both
32-bit and 64-bit machines.

The on-disk format already uses 64-bit timestamps, so nothing changes
there.

Link: http://lkml.kernel.org/r/20180122211050.1286441-1-arnd@arndb.deSigned-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

print_ip_sym() is mostly used for debugging, so I think it should print
the raw addresses.

Link: http://lkml.kernel.org/r/1514519382-405-1-git-send-email-chenhc@lemote.comSigned-off-by: NHuacai Chen <chenhc@lemote.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: "Tobin C. Harding" <me@tobin.cc>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If vm.max_map_count bumped above 2^26 (67+ mil) and system has enough RAM
to allocate all the VMAs (~12.8 GB on Fedora 27 with 200-byte VMAs), then
it should be possible to overflow 32-bit "size", pass paranoia check,
allocate very little vmalloc space and oops while writing into vmalloc
guard page...

But I didn't test this, only coredump of regular process.

Link: http://lkml.kernel.org/r/20180112203427.GA9109@avx2Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Some structure definitions that use macros trip the OPEN_BRACE test.

e.g. +struct bpf_map_def SEC("maps") control_map = {

Improve the test by using $balanced_parens instead of a .*

Miscellanea:

o Use $sline so any comments are ignored
o Correct the message output from declaration to definition
o Remove unnecessary parentheses

Link: http://lkml.kernel.org/r/db9b772999d1d2fbda3b9ee24bbca81a87837e13.1517543491.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Reported-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Using an open bracket after what seems to be a declaration can also be a
function definition and declaration argument line continuation so remove
the open bracket from the possible declaration/definition matching.

e.g.:
	int foobar(int a;
		   int *b[]);

Link: http://lkml.kernel.org/r/1515704479.9619.171.camel@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Reported-by: NSven Eckelmann <sven@narfation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Greg KH doesn't like this test so exclude the staging directory from the
implied --strict only test unless --strict is actually used on the
command-line.

Link: http://lkml.kernel.org/r/1515704034.9619.165.camel@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Declarations should start on a tabstop too.

Link: http://lkml.kernel.org/r/1b5f97673f36595956ad43329f77bf1a5546d2ff.1513976662.git.joe@perches.comSigned-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>

DEVICE_ATTR is a declaration macro that has a few alternate and
preferred forms like DEVICE_ATTR_RW, DEVICE_ATTR_RO, and DEVICE_ATTR.

As well, many uses of DEVICE_ATTR could use the preferred forms when the
show or store functions are also named in a regular form.

Suggest the preferred forms when appropriate.

Also emit a permissions warning if the the permissions are not the
typical 0644, 0444, or 0200.

Link: http://lkml.kernel.org/r/725864f363d91d1e1e6894a39fb57662eabd6d65.1513803306.git.joe@perches.comSigned-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>

Given this patch context,

+#define EFI_ST_DISK_IMG { \
+       0x00000240, "\xbe\x5b\x7c\xac\x22\xc0\x74\x0b" /* .[|.".t. */ \
+       }

the current code misreports a quoted string line continuation defect as
there is a single quote in comment.

The 'raw' line should not be tested for quote count, the comment
substituted line should be instead.

Link: http://lkml.kernel.org/r/13f2735df10c33ca846e26f42f5cce6618157200.1513698599.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Reported-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

module_param and create_proc uses with a permissions use of a single 0 are
"special" and should not emit any warning.

module_param uses with permission 0 are not visible in sysfs

create_proc uses with permission 0 use a default permission

Link: http://lkml.kernel.org/r/b6583611bb529ea6f6d43786827fddbabbab0a71.1513190059.git.joe@perches.comSigned-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
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>

Allow lines with URL to exceed the 80 char limit for improved interaction
in adaption to ongoing but undocumented practice.

  $ git grep -E '://\S{77}.*' -- '*.[ch]'

As per RFC3986 [1], the URL format allows for alphanum, +, - and .
characters in the scheme before the separator :// as long as it starts
with a letter (e.g.  https, git, f.-+).

Recognition of URIs without more context information is prone to false
positives and thus currently left out of the heuristics.

$rawline is used in the check as comments are removed from $line.

[1] https://tools.ietf.org/html/rfc3986#section-3.1

Link: http://lkml.kernel.org/r/1511355432.12667.15.camel@elementarea.netSigned-off-by: NAndreas Brauchli <andreas.brauchli@sensirion.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>

test_sort.c performs array-based and linked list sort test.  Code allows
to compile either as a loadable modules or builtin into the kernel.

Current code is not allow to unload the test_sort.ko module after
successful completion.

This patch adds support to unload the "test_sort.ko" module by adding
module_exit support.

Previous patch was implemented auto unload support by returning -EAGAIN
from module_init() function on successful case, but this approach is not
ideal.

The auto-unload might seem like a nice optimization, but it encourages
inconsistent behaviour.  And behaviour that is different from all other
normal modules.

Link: http://lkml.kernel.org/r/1513967133-6843-1-git-send-email-pravin.shedge4linux@gmail.comSigned-off-by: NPravin Shedge <pravin.shedge4linux@gmail.com>
Cc: Kostenzer Felix <fkostenzer@live.at>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

No need to get into the submenu to disable all related config entries.

This makes it easier to disable all RUNTIME_TESTS config options without
entering the submenu.  It will also enable one to see that en/dis-abled
state from the outside menu.

This is only intended to change menuconfig UI, not change the config
dependencies.

Link: http://lkml.kernel.org/r/20171209162742.7363-1-vincent.legoll@gmail.comSigned-off-by: NVincent Legoll <vincent.legoll@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We've measured that we spend ~0.6% of sys cpu time in cpumask_next_and().
It's essentially a joined iteration in search for a non-zero bit, which is
currently implemented as a lookup join (find a nonzero bit on the lhs,
lookup the rhs to see if it's set there).

Implement a direct join (find a nonzero bit on the incrementally built
join).  Also add generic bitmap benchmarks in the new `test_find_bit`
module for new function (see `find_next_and_bit` in [2] and [3] below).

For cpumask_next_and, direct benchmarking shows that it's 1.17x to 14x
faster with a geometric mean of 2.1 on 32 CPUs [1].  No impact on memory
usage.  Note that on Arm, the new pure-C implementation still outperforms
the old one that uses a mix of C and asm (`find_next_bit`) [3].

[1] Approximate benchmark code:

```
  unsigned long src1p[nr_cpumask_longs] = {pattern1};
  unsigned long src2p[nr_cpumask_longs] = {pattern2};
  for (/*a bunch of repetitions*/) {
    for (int n = -1; n <= nr_cpu_ids; ++n) {
      asm volatile("" : "+rm"(src1p)); // prevent any optimization
      asm volatile("" : "+rm"(src2p));
      unsigned long result = cpumask_next_and(n, src1p, src2p);
      asm volatile("" : "+rm"(result));
    }
  }
```

Results:
pattern1    pattern2     time_before/time_after
0x0000ffff  0x0000ffff   1.65
0x0000ffff  0x00005555   2.24
0x0000ffff  0x00001111   2.94
0x0000ffff  0x00000000   14.0
0x00005555  0x0000ffff   1.67
0x00005555  0x00005555   1.71
0x00005555  0x00001111   1.90
0x00005555  0x00000000   6.58
0x00001111  0x0000ffff   1.46
0x00001111  0x00005555   1.49
0x00001111  0x00001111   1.45
0x00001111  0x00000000   3.10
0x00000000  0x0000ffff   1.18
0x00000000  0x00005555   1.18
0x00000000  0x00001111   1.17
0x00000000  0x00000000   1.25
-----------------------------
               geo.mean  2.06

[2] test_find_next_bit, X86 (skylake)

 [ 3913.477422] Start testing find_bit() with random-filled bitmap
 [ 3913.477847] find_next_bit: 160868 cycles, 16484 iterations
 [ 3913.477933] find_next_zero_bit: 169542 cycles, 16285 iterations
 [ 3913.478036] find_last_bit: 201638 cycles, 16483 iterations
 [ 3913.480214] find_first_bit: 4353244 cycles, 16484 iterations
 [ 3913.480216] Start testing find_next_and_bit() with random-filled
 bitmap
 [ 3913.481074] find_next_and_bit: 89604 cycles, 8216 iterations
 [ 3913.481075] Start testing find_bit() with sparse bitmap
 [ 3913.481078] find_next_bit: 2536 cycles, 66 iterations
 [ 3913.481252] find_next_zero_bit: 344404 cycles, 32703 iterations
 [ 3913.481255] find_last_bit: 2006 cycles, 66 iterations
 [ 3913.481265] find_first_bit: 17488 cycles, 66 iterations
 [ 3913.481266] Start testing find_next_and_bit() with sparse bitmap
 [ 3913.481272] find_next_and_bit: 764 cycles, 1 iterations

[3] test_find_next_bit, arm (v7 odroid XU3).

[  267.206928] Start testing find_bit() with random-filled bitmap
[  267.214752] find_next_bit: 4474 cycles, 16419 iterations
[  267.221850] find_next_zero_bit: 5976 cycles, 16350 iterations
[  267.229294] find_last_bit: 4209 cycles, 16419 iterations
[  267.279131] find_first_bit: 1032991 cycles, 16420 iterations
[  267.286265] Start testing find_next_and_bit() with random-filled
bitmap
[  267.302386] find_next_and_bit: 2290 cycles, 8140 iterations
[  267.309422] Start testing find_bit() with sparse bitmap
[  267.316054] find_next_bit: 191 cycles, 66 iterations
[  267.322726] find_next_zero_bit: 8758 cycles, 32703 iterations
[  267.329803] find_last_bit: 84 cycles, 66 iterations
[  267.336169] find_first_bit: 4118 cycles, 66 iterations
[  267.342627] Start testing find_next_and_bit() with sparse bitmap
[  267.356919] find_next_and_bit: 91 cycles, 1 iterations

[courbet@google.com: v6]
  Link: http://lkml.kernel.org/r/20171129095715.23430-1-courbet@google.com
[geert@linux-m68k.org: m68k/bitops: always include <asm-generic/bitops/find.h>]
  Link: http://lkml.kernel.org/r/1512556816-28627-1-git-send-email-geert@linux-m68k.org
Link: http://lkml.kernel.org/r/20171128131334.23491-1-courbet@google.comSigned-off-by: NClement Courbet <courbet@google.com>
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Cc: Yury Norov <ynorov@caviumnetworks.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Alexey Dobriyan <adobriyan@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>

As suggested in review comments:
* printk: align numbers using whitespaces instead of tabs;
* return error value from init() to avoid calling rmmod if testing again;
* use ktime_get instead of get_cycles as some arches don't support it;

The output in dmesg (on QEMU arm64):
[   38.823430] Start testing find_bit() with random-filled bitmap
[   38.845358] find_next_bit:                20138448 ns, 163968 iterations
[   38.856217] find_next_zero_bit:           10615328 ns, 163713 iterations
[   38.863564] find_last_bit:                 7111888 ns, 163967 iterations
[   40.944796] find_first_bit:             2081007216 ns, 163968 iterations
[   40.944975]
[   40.944975] Start testing find_bit() with sparse bitmap
[   40.945268] find_next_bit:                   73216 ns,    656 iterations
[   40.967858] find_next_zero_bit:           22461008 ns, 327025 iterations
[   40.968047] find_last_bit:                   62320 ns,    656 iterations
[   40.978060] find_first_bit:                9889360 ns,    656 iterations

Link: http://lkml.kernel.org/r/20171124143040.a44jvhmnaiyedg2i@yury-thinkpadSigned-off-by: NYury Norov <ynorov@caviumnetworks.com>
Tested-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Clement Courbet <courbet@google.com>
Cc: Matthew Wilcox <mawilcox@microsoft.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>

As suggested in review comments, rename test_find_bit.c to
find_bit_benchmark.c.

Link: http://lkml.kernel.org/r/20171124143040.a44jvhmnaiyedg2i@yury-thinkpadSigned-off-by: NYury Norov <ynorov@caviumnetworks.com>
Tested-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Clement Courbet <courbet@google.com>
Cc: Matthew Wilcox <mawilcox@microsoft.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>

stackdepot used to call memcmp(), which compiler tools normally
instrument, therefore every lookup used to unnecessarily call instrumented
code.  This is somewhat ok in the case of KASAN, but under KMSAN a lot of
time was spent in the instrumentation.

Link: http://lkml.kernel.org/r/20171117172149.69562-1-glider@google.comSigned-off-by: NAlexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Behaviour of bitmap_fill() differs from bitmap_zero() in a way how bits
behind bitmap are handed.  bitmap_zero() clears entire bitmap by unsigned
long boundary, while bitmap_fill() mimics bitmap_set().

Here we change bitmap_fill() behaviour to be consistent with bitmap_zero()
and add a note to documentation.

The change might reveal some bugs in the code where unused bits are
handled differently and in such cases bitmap_set() has to be used.

Link: http://lkml.kernel.org/r/20180109172430.87452-4-andriy.shevchenko@linux.intel.comSigned-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yury Norov <ynorov@caviumnetworks.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since we have separate explicit test cases for bitmap_zero() /
bitmap_clear() and bitmap_fill() / bitmap_set(), clean up
test_zero_fill_copy() to only test bitmap_copy() functionality and thus
rename a function to reflect the changes.

While here, replace bitmap_fill() by bitmap_set() with proper values.

Link: http://lkml.kernel.org/r/20180109172430.87452-3-andriy.shevchenko@linux.intel.comSigned-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NYury Norov <ynorov@caviumnetworks.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>