Jingoo Han [Thu, 3 Apr 2014 21:49:45 +0000 (14:49 -0700)]
rtc: rtc-sirfsoc: remove unnecessary OOM messages
The site-specific OOM messages are unnecessary, because they duplicate
the MM subsystem generic OOM message.
Signed-off-by: Jingoo Han <jg1.han@samsung.com> Acked-by: Barry Song <Baohua.Song@csr.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Luis Henriques [Thu, 3 Apr 2014 21:49:34 +0000 (14:49 -0700)]
binfmt_misc: add missing 'break' statement
A missing 'break' statement in bm_status_write() results in a user program
receiving '3' when doing the following:
write(fd, "-1", 2);
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A commit hook for the Gerrit code review server [1] inserts change
identifiers so Gerrit can track patches through multiple revisions.
These identifiers are noise in the context of the upstream kernel.
(Many Gerrit servers are private. Even given a public instance, given
only a Change-Id, one must guess which server a change was tracked on.
Patches submitted to the Linux kernel mailing lists should be able to
stand on their own. If it's truly useful to reference code review on a
Gerrit server, a URL is a much clearer way to do so.) Thus, issue an
error when a Change-Id line is encountered before the Signed-off-by.
Signed-off-by: Christopher Covington <cov@codeaurora.org> Cc: Joe Perches <joe@perches.com> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joe Perches [Thu, 3 Apr 2014 21:49:28 +0000 (14:49 -0700)]
checkpatch: net and drivers/net: warn on missing blank line after variable declaration
Networking prefers this style, so warn when it's not used.
Networking uses:
void foo(int bar)
{
int baz;
code...
}
not
void foo(int bar)
{
int baz;
code...
}
There are a limited number of false positives when using macros to
declare variables like:
WARNING: networking uses a blank line after declarations
#330: FILE: net/ipv4/inet_hashtables.c:330:
+ int dif = sk->sk_bound_dev_if;
+ INET_ADDR_COOKIE(acookie, saddr, daddr)
Signed-off-by: Joe Perches <joe@perches.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch.pl: modify warning message for printk usage
Modify warning message when printk is used in a patch. It mentions to
use subsystem_dbg instead of netdev_dbg as the first preferred format of
logging debug messages.
Signed-off-by: Yogesh Chaudhari <mr.yogesh@gmail.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joe Perches [Thu, 3 Apr 2014 21:49:20 +0000 (14:49 -0700)]
checkpatch: ignore networking block comment style first lines in file
It's very common to have normal block comments for the initial comments
of a file description preface.
So for files in drivers/net and net/ don't emit a warning when the first
comment block in the file uses the normal block comment style and not
the networking block comment style.
Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Using any of these outside of include/uapi/ isn't preferred as using the
function without __constant_ is identical when the argument is a
constant.
Signed-off-by: Joe Perches <joe@perches.com> Cc: Andy Whitcroft <apw@canonical.com> Cc: Simon Wunderlich <sw@simonwunderlich.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joe Perches [Thu, 3 Apr 2014 21:49:11 +0000 (14:49 -0700)]
checkpatch: add test for long udelay
Holger reported:
: The macro udelay cannot handle large values because of loss-of-precision.
:
: IMHO udelay on ARM is broken, because it also cannot work with fast
: ARM processors (where bogomips >= 3355, which is in sight now). It's
: just not broken enough that someone did something against it ... so
: the current kludge is good enough.
Until then, warn on long udelay uses.
Also fix uses of $line that should have been $herecurr.
Signed-off-by: Joe Perches <joe@perches.com> Reported-by: Holger Schurig <holgerschurig@gmail.com> Cc: Sujith Manoharan <sujith@msujith.org> Cc: John Linville <linville@tuxdriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib/decompress_inflate.c: include appropriate header file
Include appropriate header file include/linux/decompress/inflate.h in
lib/decompress_inflate.c because it has prototype declaration of
function defined in lib/decompress_inflate.c.
Also, fix the guard around the header file
include/linux/decompress/inflate.h to use a more unique guard symbol.
This avoids conflict with the INFLATE_H defined by
zlib_inflate/inflate.h.
This eliminates the following warning in lib/decompress_inflate.c:
lib/decompress_inflate.c:35:17: warning: no previous prototype for `gunzip' [-Wmissing-prototypes]
lib/clz_ctz.c: add prototype declarations in lib/clz_ctz.c
Add prototype declarations of functions in lib/clz_ctz.c. These
functions are required by GCC builtins and hence can not be removed
despite of their unreferenced appearance in kernel source.
This eliminates the following warning in lib/clz_ctz.c:
lib/clz_ctz.c:16:12: warning: no previous prototype for `__ctzsi2' [-Wmissing-prototypes]
lib/clz_ctz.c:22:12: warning: no previous prototype for `__clzsi2' [-Wmissing-prototypes]
lib/clz_ctz.c:44:12: warning: no previous prototype for `__clzdi2' [-Wmissing-prototypes]
lib/clz_ctz.c:50:12: warning: no previous prototype for `__ctzdi2' [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Chanho Min <chanho.min@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Daniel Borkmann [Thu, 3 Apr 2014 21:49:08 +0000 (14:49 -0700)]
lib/random32.c: minor cleanups and kdoc fix
These are just some very minor and misc cleanups in the PRNG. In
prandom_u32() we store the result in an unsigned long which is
unnecessary as it should be u32 instead that we get from
prandom_u32_state(). prandom_bytes_state()'s comment is in kdoc format,
so change it into such as it's done everywhere else. Also, use the
normal comment style for the header comment. Last but not least for
readability, add some newlines.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Steven Rostedt [Thu, 3 Apr 2014 21:49:07 +0000 (14:49 -0700)]
lib/devres.c: fix some sparse warnings
Having a discussion about sparse warnings in the kernel, and that we
should clean them up, I decided to pick a random file to do so. This
happened to be devres.c which gives the following warnings:
CHECK lib/devres.c
lib/devres.c:83:9: warning: cast removes address space of expression
lib/devres.c:117:31: warning: incorrect type in return expression (different address spaces)
lib/devres.c:117:31: expected void [noderef] <asn:2>*
lib/devres.c:117:31: got void *
lib/devres.c:125:31: warning: incorrect type in return expression (different address spaces)
lib/devres.c:125:31: expected void [noderef] <asn:2>*
lib/devres.c:125:31: got void *
lib/devres.c:136:26: warning: incorrect type in assignment (different address spaces)
lib/devres.c:136:26: expected void [noderef] <asn:2>*[assigned] dest_ptr
lib/devres.c:136:26: got void *
lib/devres.c:226:9: warning: cast removes address space of expression
Mostly it's just the use of typecasting to void * without adding
__force, or returning ERR_PTR(-ESOMEERR) without typecasting to a
__iomem type.
I added a helper macro IOMEM_ERR_PTR() that does the typecast to make
the code a little nicer than adding ugly typecasts to the code.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Liu Ying [Thu, 3 Apr 2014 21:48:55 +0000 (14:48 -0700)]
backlight: update backlight status when necessary
We don't have to update a backlight status every time a blanking or
unblanking event comes because the backlight status may have already
been what we want. Another thought is that one backlight device may be
shared by multiple framebuffers. We don't hope blanking one of the
framebuffers may turn the backlight off for all the other framebuffers,
since they are likely being active to display something.
This patch makes the backlight status be updated only when the relevant
backlight device's use count changes from zero to one or from one to
zero.
Signed-off-by: Liu Ying <Ying.Liu@freescale.com> Cc: Jingoo Han <jg1.han@samsung.com> Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Liu Ying [Thu, 3 Apr 2014 21:48:54 +0000 (14:48 -0700)]
backlight: update bd state & fb_blank properties when necessary
We don't have to update the state and fb_blank properties of a backlight
device every time a blanking or unblanking event comes because they may
have already been what we want. Another thought is that one backlight
device may be shared by multiple framebuffers. The backlight driver
should take the backlight device as a resource shared by all the
associated framebuffers.
This patch adds some logic to record each framebuffer's backlight usage
to determine the backlight device use count and whether the two
properties should be updated or not. To be more specific, only one
unblank operation on a certain blanked framebuffer may increase the
backlight device's use count by one, while one blank operation on a
certain unblanked framebuffer may decrease the use count by one, because
the userspace is likely to unblank an unblanked framebuffer or blank a
blanked framebuffer.
Signed-off-by: Liu Ying <Ying.Liu@freescale.com> Cc: Jingoo Han <jg1.han@samsung.com> Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Simek [Thu, 3 Apr 2014 21:48:52 +0000 (14:48 -0700)]
MAINTAINERS: microblaze: use LKML as mailing list
microblaze-uclinux mailing list is almost dead and it is just causing
troubles for non subscribers which are getting email about waiting for
moderator. Approval never happens. Move it to LKML.
Signed-off-by: Michal Simek <michal.simek@xilinx.com> Reported-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MAINTAINERS: addition of Dialog Semiconductor files
Dialog Semiconductor Ltd would like to add a new section called DIALOG
SEMICONDUCTOR DRIVERS which contains a new e-mail address that can cover
all Dialog supported drivers: support.opensource@diasemi.com.
Signed-off-by: Opensource [Steve Twiss] <stwiss.opensource@diasemi.com> Signed-off-by: David Dajun Chen <david.chen@diasemi.com> Cc: Mark Brown <broonie@linaro.org> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Max Filippov [Thu, 3 Apr 2014 21:48:48 +0000 (14:48 -0700)]
MAINTAINERS: add xtensa irqchips to xtensa port entry
Now that irqchip drivers for xtensa live outside arch/xtensa we'd like
to add them to our maintenance list.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Cc: Chris Zankel <chris@zankel.net> Cc: Marc Gauthier <marc@cadence.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jingoo Han [Thu, 3 Apr 2014 21:48:46 +0000 (14:48 -0700)]
MAINTAINERS: add backlight co-maintainers
Bryan Wu and Lee Jones volunteer to maintain backlight drivers and help
to setup git-tree for backlight subsystem. Thus, I add them as
backlight co-maintainers.
Signed-off-by: Jingoo Han <jg1.han@samsung.com> Acked-by: Bryan Wu <cooloney@gmail.com> Acked-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
======================================================
[ INFO: possible circular locking dependency detected ]
3.10.0 #2 Tainted: G O
-------------------------------------------------------
sh/1271 is trying to acquire lock:
(console_lock){+.+.+.}, at: console_cpu_notify+0x20/0x2c
but task is already holding lock:
(cpu_hotplug.lock){+.+.+.}, at: cpu_hotplug_begin+0x2c/0x58
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (cpu_hotplug.lock){+.+.+.}:
lock_acquire+0x98/0x12c
mutex_lock_nested+0x50/0x3d8
cpu_hotplug_begin+0x2c/0x58
_cpu_up+0x24/0x154
cpu_up+0x64/0x84
smp_init+0x9c/0xd4
kernel_init_freeable+0x78/0x1c8
kernel_init+0x8/0xe4
ret_from_fork+0x14/0x2c
There are three locks involved in two sequence:
a) pm suspend:
console_lock (@suspend_console())
cpu_add_remove_lock (@disable_nonboot_cpus())
cpu_hotplug.lock (@_cpu_down())
b) Plug-out CPUx:
cpu_add_remove_lock (@(cpu_down())
cpu_hotplug.lock (@_cpu_down())
console_lock (@console_cpu_notify()) => Lockdeps prints warning log.
There should be not real deadlock, as flag of console_suspended can
protect this.
Although console_suspend() releases console_sem, it doesn't tell lockdep
about it. That results in the lockdep warning about circular locking
when doing the following: enter suspend -> resume -> plug-out CPUx (echo
0 > cpux/online)
Fix the problem by telling lockdep we actually released the semaphore in
console_suspend() and acquired it again in console_resume().
Signed-off-by: Jane Li <jiel@marvell.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Petr Mladek [Thu, 3 Apr 2014 21:48:43 +0000 (14:48 -0700)]
printk: do not compute the size of the message twice
This is just a tiny optimization. It removes duplicate computation of
the message size.
Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Petr Mladek [Thu, 3 Apr 2014 21:48:42 +0000 (14:48 -0700)]
printk: use also the last bytes in the ring buffer
It seems that we have newer used the last byte in the ring buffer. In
fact, we have newer used the last 4 bytes because of padding.
First problem is in the check for free space. The exact number of free
bytes is enough to store the length of data.
Second problem is in the check where the ring buffer is rotated. The
left side counts the first unused index. It is unused, so it might be
the same as the size of the buffer.
Note that the first problem has to be fixed together with the second
one. Otherwise, the buffer is rotated even when there is enough space
on the end of the buffer. Then the beginning of the buffer is rewritten
and valid entries get corrupted.
Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Petr Mladek [Thu, 3 Apr 2014 21:48:41 +0000 (14:48 -0700)]
printk: add comment about tricky check for text buffer size
There is no check for potential "text_len" overflow. It is not needed
because only valid level is detected. It took me some time to
understand why. It would deserve a comment ;-)
Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Petr Mladek [Thu, 3 Apr 2014 21:48:39 +0000 (14:48 -0700)]
printk: remove obsolete check for log level "c"
The kernel log level "c" was removed in commit 61e99ab8e35a ("printk:
remove the now unnecessary "C" annotation for KERN_CONT"). It is no
longer detected in printk_get_level(). Hence we do not need to check it
in vprintk_emit.
Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Petr Mladek [Thu, 3 Apr 2014 21:48:38 +0000 (14:48 -0700)]
printk: remove duplicated check for log level
The check for the exact log level is already done in printk_get_level.
We do not need to duplicate it in printk_skip_level.
Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ryan Mallon [Thu, 3 Apr 2014 21:48:37 +0000 (14:48 -0700)]
vsprintf: remove %n handling
All in-kernel users of %n in format strings have now been removed and
the %n directive is ignored. Remove the handling of %n so that it is
treated the same as any other invalid format string directive. Keep a
warning in place to deter new instances of %n in format strings.
Signed-off-by: Ryan Mallon <rmallon@gmail.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Paul Gortmaker [Thu, 3 Apr 2014 21:48:35 +0000 (14:48 -0700)]
kernel: audit/fix non-modular users of module_init in core code
Code that is obj-y (always built-in) or dependent on a bool Kconfig
(built-in or absent) can never be modular. So using module_init as an
alias for __initcall can be somewhat misleading.
Fix these up now, so that we can relocate module_init from init.h into
module.h in the future. If we don't do this, we'd have to add module.h
to obviously non-modular code, and that would be a worse thing.
The audit targets the following module_init users for change:
kernel/user.c obj-y
kernel/kexec.c bool KEXEC (one instance per arch)
kernel/profile.c bool PROFILING
kernel/hung_task.c bool DETECT_HUNG_TASK
kernel/sched/stats.c bool SCHEDSTATS
kernel/user_namespace.c bool USER_NS
Note that direct use of __initcall is discouraged, vs. one of the
priority categorized subgroups. As __initcall gets mapped onto
device_initcall, our use of subsys_initcall (which makes sense for these
files) will thus change this registration from level 6-device to level
4-subsys (i.e. slightly earlier). However no observable impact of that
difference has been observed during testing.
Also, two instances of missing ";" at EOL are fixed in kexec.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
samples/seccomp/Makefile: do not build tests if cross-compiling for MIPS
The Makefile is designed to use the host toolchain so it may be unsafe
to build the tests if the kernel has been configured and built for
another architecture. This fixes a build problem when the kernel has
been configured and built for the MIPS architecture but the host is not
MIPS (cross-compiled). The MIPS syscalls are only defined if one of the
following is true:
Of course, none of these make sense on a non-MIPS toolchain and the
following build problem occurs when building on a non-MIPS host.
linux/usr/include/linux/kexec.h:50: userspace cannot reference function or variable defined in the kernel
samples/seccomp/bpf-direct.c: In function `emulator':
samples/seccomp/bpf-direct.c:76:17: error: `__NR_write' undeclared (first use in this function)
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Most of the mechanical portions of SubmittingPatches exist to help patch
submitters replicate the output of git. Mention this explicitly, both
as a reminder that git will help with this process, and as signposting
to let git users know what they can safely skip.
Signed-off-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Borislav Petkov <bp@suse.de> Cc: Rob Landley <rob@landley.net> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SubmittingPatches: add recommendation for mailing list references
SubmittingPatches already mentions referencing bugs fixed by a commit,
but doesn't mention citing relevant mailing list discussions. Add a
note to that effect, along with a recommendation to use the
https://lkml.kernel.org/ redirector.
Portions based on text from git's SubmittingPatches.
Signed-off-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Borislav Petkov <bp@suse.de> Cc: Rob Landley <rob@landley.net> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SubmittingPatches: add style recommendation to use imperative descriptions
Most commit messages use this style, and the recommendation frequently
comes up in discussions (especially in response to patches that don't
use it), but that recommendation doesn't actually appear anywhere in
Documentation. Add this style guideline to SubmittingPatches, using the
description from git's SubmittingPatches.
Signed-off-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Borislav Petkov <bp@suse.de> Cc: Rob Landley <rob@landley.net> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Wang YanQing [Thu, 3 Apr 2014 21:48:26 +0000 (14:48 -0700)]
kernel/groups.c: remove return value of set_groups
After commit 6307f8fee295 ("security: remove dead hook task_setgroups"),
set_groups will always return zero, so we could just remove return value
of set_groups.
This patch reduces code size, and simplfies code to use set_groups,
because we don't need to check its return value any more.
[akpm@linux-foundation.org: remove obsolete claims from set_groups() comment] Signed-off-by: Wang YanQing <udknight@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Serge Hallyn <serge.hallyn@canonical.com> Cc: Eric Paris <eparis@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Raghavendra K T [Thu, 3 Apr 2014 21:48:23 +0000 (14:48 -0700)]
mm/readahead.c: fix readahead failure for memoryless NUMA nodes and limit readahead pages
Currently max_sane_readahead() returns zero on the cpu whose NUMA node
has no local memory which leads to readahead failure. Fix this
readahead failure by returning minimum of (requested pages, 512). Users
running applications on a memory-less cpu which needs readahead such as
streaming application see considerable boost in the performance.
Result:
fadvise experiment with FADV_WILLNEED on a PPC machine having memoryless
CPU with 1GB testfile (12 iterations) yielded around 46.66% improvement.
fadvise experiment with FADV_WILLNEED on a x240 machine with 1GB
testfile 32GB* 4G RAM numa machine (12 iterations) showed no impact on
the normal NUMA cases w/ patch.
Kernel Avg Stddev
base 7.4975 3.92%
patched 7.4174 3.26%
[Andrew: making return value PAGE_SIZE independent] Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Acked-by: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We release the slab_mutex while calling sysfs_slab_add from
__kmem_cache_create since commit 66c4c35c6bc5 ("slub: Do not hold
slub_lock when calling sysfs_slab_add()"), because kobject_uevent called
by sysfs_slab_add might block waiting for the usermode helper to exec,
which would result in a deadlock if we took the slab_mutex while
executing it.
However, apart from complicating synchronization rules, releasing the
slab_mutex on kmem cache creation can result in a kmemcg-related race.
The point is that we check if the memcg cache exists before going to
__kmem_cache_create, but register the new cache in memcg subsys after
it. Since we can drop the mutex there, several threads can see that the
memcg cache does not exist and proceed to creating it, which is wrong.
Fortunately, recently kobject_uevent was patched to call the usermode
helper with the UMH_NO_WAIT flag, making the deadlock impossible.
Therefore there is no point in releasing the slab_mutex while calling
sysfs_slab_add, so let's simplify kmem_cache_create synchronization and
fix the kmemcg-race mentioned above by holding the slab_mutex during the
whole cache creation path.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Greg KH <greg@kroah.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently kobject_uevent has somewhat unpredictable semantics. The
point is, since it may call a usermode helper and wait for it to execute
(UMH_WAIT_EXEC), it is impossible to say for sure what lock dependencies
it will introduce for the caller - strictly speaking it depends on what
fs the binary is located on and the set of locks fork may take. There
are quite a few kobject_uevent's users that do not take this into
account and call it with various mutexes taken, e.g. rtnl_mutex,
net_mutex, which might potentially lead to a deadlock.
Since there is actually no reason to wait for the usermode helper to
execute there, let's make kobject_uevent start the helper asynchronously
with the aid of the UMH_NO_WAIT flag.
Personally, I'm interested in this, because I really want kobject_uevent
to be called under the slab_mutex in the slub implementation as it used
to be some time ago, because it greatly simplifies synchronization and
automatically fixes a kmemcg-related race. However, there was a
deadlock detected on an attempt to call kobject_uevent under the
slab_mutex (see https://lkml.org/lkml/2012/1/14/45), which was reported
to be fixed by releasing the slab_mutex for kobject_uevent.
Unfortunately, there was no information about who exactly blocked on the
slab_mutex causing the usermode helper to stall, neither have I managed
to find this out or reproduce the issue.
BTW, this is not the first attempt to make kobject_uevent use
UMH_NO_WAIT. Previous one was made by commit f520360d93cd ("kobject:
don't block for each kobject_uevent"), but it was wrong (it passed
arguments allocated on stack to async thread) so it was reverted in 05f54c13cd0c ("Revert "kobject: don't block for each kobject_uevent".").
It targeted on speeding up the boot process though.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Greg KH <greg@kroah.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dave Hansen [Thu, 3 Apr 2014 21:48:19 +0000 (14:48 -0700)]
drop_caches: add some documentation and info message
There is plenty of anecdotal evidence and a load of blog posts
suggesting that using "drop_caches" periodically keeps your system
running in "tip top shape". Perhaps adding some kernel documentation
will increase the amount of accurate data on its use.
If we are not shrinking caches effectively, then we have real bugs.
Using drop_caches will simply mask the bugs and make them harder to
find, but certainly does not fix them, nor is it an appropriate
"workaround" to limit the size of the caches. On the contrary, there
have been bug reports on issues that turned out to be misguided use of
cache dropping.
Dropping caches is a very drastic and disruptive operation that is good
for debugging and running tests, but if it creates bug reports from
production use, kernel developers should be aware of its use.
Add a bit more documentation about it, a syslog message to track down
abusers, and vmstat drop counters to help analyze problem reports.
[akpm@linux-foundation.org: checkpatch fixes]
[hannes@cmpxchg.org: add runtime suppression control] Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch removes read_cache_page_async() which wasn't really needed
anywhere and simplifies the code around it a bit.
read_cache_page_async() is useful when we want to read a page into the
cache without waiting for it to complete. This happens when the
appropriate callback 'filler' doesn't complete its read operation and
releases the page lock immediately, and instead queues a different
completion routine to do that. This never actually happened anywhere in
the code.
read_cache_page_async() had 3 different callers:
- read_cache_page() which is the sync version, it would just wait for
the requested read to complete using wait_on_page_read().
- JFFS2 would call it from jffs2_gc_fetch_page(), but the filler
function it supplied doesn't do any async reads, and would complete
before the filler function returns - making it actually a sync read.
- CRAMFS would call it using the read_mapping_page_async() wrapper, with
a similar story to JFFS2 - the filler function doesn't do anything that
reminds async reads and would always complete before the filler function
returns.
To sum it up, the code in mm/filemap.c never took advantage of having
read_cache_page_async(). While there are filler callbacks that do async
reads (such as the block one), we always called it with the
read_cache_page().
This patch adds a mandatory wait for read to complete when adding a new
page to the cache, and removes read_cache_page_async() and its wrappers.
I've realized that there's no need for do_huge_pmd_wp_zero_page_fallback().
We can just split zero page with split_huge_page_pmd() and return
VM_FAULT_FALLBACK. handle_pte_fault() will handle write-protection
fault for us.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
linux/mm.h does not define a prototype, but mm/page_alloc.c defines
the function.
Hence, compiler reports the following warning:
mm/page_alloc.c:4300:15: warning: no previous prototype for `__early_pfn_to_nid' [-Wmissing-prototypes]
- defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID)
The architecture defines the function, and linux/mm.h has a
prototype.
Thus, join the conditions of Case 2 and 3 ie eliminate the ifdef
condition of CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID to eliminate the missing
prototype warning from file mm/page_alloc.c.
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mark functions as static in page_cgroup.c because they are not used
outside this file.
This eliminates the following warning in mm/page_cgroup.c:
mm/page_cgroup.c:177:6: warning: no previous prototype for `__free_page_cgroup' [-Wmissing-prototypes]
mm/page_cgroup.c:190:15: warning: no previous prototype for `online_page_cgroup' [-Wmissing-prototypes]
mm/page_cgroup.c:225:15: warning: no previous prototype for `offline_page_cgroup' [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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