As Bruce Fields pointed out, kstrto* is currently lacking kerneldoc
comments. This patch adds kerneldoc comments to common variants of
kstrto*: kstrto(u)l, kstrto(u)ll and kstrto(u)int.
Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Joe Perches <joe@perches.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
keys-ecryptfs.txt was missing from 00-INDEX.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Option parsing code expects an unsigned integer for the codepage option,
but prefixes and stores this option with "cp" before passing to
load_nls(). This makes the displayed option in /proc an invalid one.
Strip the prefix when printing so that the displayed option is valid for
reuse.
Signed-off-by: Dave Reisner <dreisner@archlinux.org>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
parse_options() is supposed to return value < 0 on error however we
returned 0 (success) in a lot of cases. This actually was not a problem
in practice because match_token() used by parse_options() is clever and
catches most of the problems for us.
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
So far FAT either offsets time stamps by sys_tz.minuteswest or leaves them
as they are (when tz=UTC mount option is used). However in some cases it
is useful if one can specify time stamp offset on his own (e.g. when time
zone of the camera connected is different from time zone of the computer,
or when HW clock is in UTC and thus sys_tz.minuteswest == 0).
So provide a mount option time_offset= which allows user to specify offset
in minutes that should be applied to time stamps on the filesystem.
akpm: this code would work incorrectly when used via `mount -o remount',
because cached inodes would not be updated. But fatfs's fat_remount() is
basically a no-op anyway.
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change fatfs so that a warning is emitted when an attempt is made to mount
a filesystem with the unsupported `discard' option.
ext4 aready does this: http://patchwork.ozlabs.org/patch/192668/
Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Amit Sahrawat <amit.sahrawat83@gmail.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A driver for the DA9055 PMIC. This has a dependency upon the DA9055 MFD
core.
Functionally tested on Samsung SMDKV6410.
Signed-off-by: David Dajun Chen <dchen@diasemi.com>
Signed-off-by: Ashish Jangam <ashish.jangam@kpitcummins.com>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This eliminates having an #ifdef returning NULL for the case when OF is
disabled.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Enabling RTC HW block depends on the default value of TPS65910 register.
In some mode, RTC block is disabled by default.(eg. AM3517 Craneboard) In
this case, RTC_PWDN(RTC power down) bit should be cleared to enable the
RTC HW block.
This patch also works in case that RTC block is active by default, because
there is no side effect even if the bit is updated again.
Tested on AM3517 Craneboard.
Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Acked-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Sivaram Nair <sivaramn@nvidia.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This code is under #if 0 and not used.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
rtc-s3c driver is modified to use devm_request_and_ioremap() (combining
request_mem_region and ioremap), devm_clk_get() and devm_request_irq()
APIs. Since this removes the necessity of freeing the related resources
the return path is also simplified.
Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
err_nores label redirects to a simple return statement. Move the return
statement to caller location and remove the label.
Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add an RTC driver for PCF8523 chips by NXP Semiconductors. No support is
currently provided for the alarm and interrupt functions. Only the time
and date functionality is implemented.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use devm_kzalloc() and remove the error path free and the unload free as
devm functions take care of freeing resources.
Signed-off-by: Devendra Naga <devendra.aaru@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Miguel Aguilar <miguel.aguilar@ridgerun.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
rtc_device_register() returns a pointer containing error code in case
of error. Use that in the error return.
Signed-off-by: Devendra Naga <devendra.aaru@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Miguel Aguilar <miguel.aguilar@ridgerun.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A cosmetic change to rename the irq name to match the device name.
Signed-off-by: Sivaram Nair <sivaramn@nvidia.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The applications can set the RTC hardware to trigger interrupts in one
of three modes:
* AIE: Alarm interrupt
* UIE: Update interrupt (ie: once per second)
* PIE: Periodic interrupt (sub-second irqs)
The above defined 3 modes are to be supported in the RTC HW in form of
interrupts. The SPEAr RTC hardware does not support the later two modes.
There have been refinements in the RTC core in mainline related to
use of timer queue infrastructure to manage events in RTC. Please refer
the below mentioned patch for details:
* RTC: Rework RTC code to use timerqueue for events
* SHA ID: 6610e0893b
There have been provisions added to support hardware that do not have
support the UIE mode. Please refer the following patch.
* rtc: Provide flag for rtc devices that don't support UIE
* SHA ID: 4a649903f9
The patch makes use of the provision defined in the above patch to
update the hardware status of UIE mode.
Signed-off-by: Deepak Sikri <deepak.sikri@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
clk_{un}prepare is mandatory for platforms using common clock framework.
Because for SPEAr we don't do anything in clk_{un}prepare() calls, just
call them once in probe/remove.
Signed-off-by: Deepak Sikri <deepak.sikri@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Free the rtc-spear driver from tension of freeing resources :) devm_*
derivatives of multiple routines are used while allocating resources,
which would be freed automatically by kernel.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Deepak Sikri <deepak.sikri@st.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In case of error, test_init() needs to call platform_device_del() instead
of platform_device_unregister(). Otherwise, we may call
platform_device_put() twice.
dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)
[akpm@linux-foundation.org: improve label naming]
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add device tree support to the rtc-imxdi driver.
Signed-off-by: Roland Stigge <stigge@antcom.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Enable support for i.MX53 in addition to i.MX25 by enabling the driver on
ARCH_MXC generally.
Signed-off-by: Roland Stigge <stigge@antcom.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
OMAP1 RTC driver is used in multiple devices like, OMAPL138 and AM33XX.
Driver currently doesn't handle any clocks, which may be right for OMAP1
architecture but in case of AM33XX, the clock/module needs to be enabled
in order to access the registers.
So convert this driver to runtime pm, which internally handles rest.
[afzal@ti.com: handle error path]
Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Afzal Mohammed <afzal@ti.com>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Daniel Mack <zonque@gmail.com>
Cc: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
rtc-omap driver can be reused for AM33xx RTC. Provide dependency in
Kconfig.
Signed-off-by: Afzal Mohammed <afzal@ti.com>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Daniel Mack <zonque@gmail.com>
Cc: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Enhance rtc-omap driver with DT capability
Signed-off-by: Afzal Mohammed <afzal@ti.com>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Daniel Mack <zonque@gmail.com>
Cc: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
rtc-omap driver is now capable of handling kicker mechanism, hence remove
kicker handling at platform level, instead provide proper device name so
that driver can handle kicker mechanism by itself
Signed-off-by: Afzal Mohammed <afzal@ti.com>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Daniel Mack <zonque@gmail.com>
Cc: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
OMAP RTC IP can have kicker feature. This prevents spurious writes to
register. To write to registers kicker lock has to be released.
Procedure to do it as follows,
1. write to kick0 register, 0x83e70b13
2. write to kick1 register, 0x95a4f1e0
Writing value other than 0x83e70b13 to kick0 enables write locking, more
details about kicker mechanism can be found in section 20.3.3.5.3 of
AM335X TRM @www.ti.com/am335x
Here id table information is added and is used to distinguish those that
require kicker handling and the ones that doesn't need it. There are more
features in the newer IP's compared to legacy ones other than kicker,
which driver currently doesn't handle, supporting additional features
would be easier with the addition of id table.
Older IP (of OMAP1) doesn't have revision register as per TRM, so revision
register can't be relied always to find features, hence id table is being
used.
While at it, replace __raw_writeb/__raw_readb with writeb/readb; this
driver is used on ARMv7 (AM335X SoC)
Signed-off-by: Afzal Mohammed <afzal@ti.com>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Daniel Mack <zonque@gmail.com>
Cc: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If elf_core_dump() is called and fill_note_info() fails in the kmalloc()
then it returns 0 but has not yet initialised all the needed fields. As a
result we do a kfree(randomness) after correctly skipping the thread data.
[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Store the camelcase variables in a hash and only emit a warning on the
first use of each new variable.
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Even though the kernel doesn't support using floating point constants,
add a regex for them.
Support forms like: 0x123p1, 123e-1, 1.23, 1.5e23f
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hexadecimal values are current found in 2 parts. A hex constant like
0x123456abcdef is found as 0 and then x123456abcdef and later coalesced.
Instead, reverse the order of the 2 searches in $Constant to find 0x
first, then 0 so that the entire hex constant is found all at once.
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
switch default case is sometimes written as "default:;". This can cause
new cases added below the default to be defective.
Suggest adding a break; after empty default cases to avoid fallthrough
defects.
Fixed indentation in the other semicolon test above it.
Suggested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
spinlock_t should always be used.
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: "Luis R. Rodriguez" <mcgrof@do-not-panic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Blank lines around braces are not unnecessary. Emit a message on the use
of these blank lines only when using --strict.
int foo(int bar)
{
something or other....
}
is generally written in the kernel as:
int foo(int bar)
{
something or other...
}
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Preprocessor directives and asm statements should be allowed to have a
line continuation.
Signed-off-by: Joe Perches <joe@perches.com>
Tested-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some projects might want a longer line length so allow a command line
--max-line-length=n control over the long line warnings. The default line
length is 80.
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Constantine Shulyupin <const@makelinux.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Consolidate the if (foo) bar(foo) detectors into a single check. Add
debugfs_remove and family.
Based on a patch by Constantine Shulyupin.
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Cc: Constantine Shulyupin <const@MakeLinux.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>
In commit 9c0ece069b ("Get rid of Documentation/feature-removal.txt"),
Linus removes feature-removal-schedule.txt from Documentation, but there
is still some reference to this file. So remove them.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Acked-by: Andy Whitcroft <apw@canonical.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>
This config item has not carried much meaning for a while now and is
almost always enabled by default. As agreed during the Linux kernel
summit, it is being removed. This will discourage future addition of
CONFIG_EXPERIMENTAL while it is being phased out.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Whitcroft <apw@canonical.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>
When the previous line is not a line continuation and the current line has
a line continuation but is not a #define, emit a warning.
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This function is used by sparc, powerpc tile and arm64 for compat support.
The patch adds a generic implementation with a wrapper for PowerPC to do
the u32->int sign extension.
The reason for a single patch covering powerpc, tile, sparc and arm64 is
to keep it bisectable, otherwise kernel building may fail with mismatched
function declarations.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com> [for tile]
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: 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>
Fix this warning:
lib/rbtree_test.c: In function `check':
lib/rbtree_test.c:121: warning: `blacks' may be used uninitialized in this function
Signed-off-by: Cong Ding <dinggnu@gmail.com>
Cc: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add lockdep annotations. Not only this can help to find the potential
problems, we do not want the false warnings if, say, the task takes two
different percpu_rw_semaphore's for reading. IOW, at least ->rw_sem
should not use a single class.
This patch exposes this internal lock to lockdep so that it represents the
whole percpu_rw_semaphore. This way we do not need to add another "fake"
->lockdep_map and lock_class_key. More importantly, this also makes the
output from lockdep much more understandable if it finds the problem.
In short, with this patch from lockdep pov percpu_down_read() and
percpu_up_read() acquire/release ->rw_sem for reading, this matches the
actual semantics. This abuses __up_read() but I hope this is fine and in
fact I'd like to have down_read_no_lockdep() as well,
percpu_down_read_recursive_readers() will need it.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
percpu_rw_semaphore->writer_mutex was only added to simplify the initial
rewrite, the only thing it protects is clear_fast_ctr() which otherwise
could be called by multiple writers. ->rw_sem is enough to serialize the
writers.
Kill this mutex and add "atomic_t write_ctr" instead. The writers
increment/decrement this counter, the readers check it is zero instead of
mutex_is_locked().
Move atomic_add(clear_fast_ctr(), slow_read_ctr) under down_write() to
avoid the race with other writers. This is a bit sub-optimal, only the
first writer needs this and we do not need to exclude the readers at this
stage. But this is simple, we do not want another internal lock until we
add more features.
And this speeds up the write-contended case. Before this patch the racing
writers sleep in synchronize_sched_expedited() sequentially, with this
patch multiple synchronize_sched_expedited's can "overlap" with each
other. Note: we can do more optimizations, this is only the first step.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the writer does msleep() plus synchronize_sched() 3 times to
acquire/release the semaphore, and during this time the readers are
blocked completely. Even if the "write" section was not actually started
or if it was already finished.
With this patch down_write/up_write does synchronize_sched() twice and
down_read/up_read are still possible during this time, just they use the
slow path.
percpu_down_write() first forces the readers to use rw_semaphore and
increment the "slow" counter to take the lock for reading, then it
takes that rw_semaphore for writing and blocks the readers.
Also. With this patch the code relies on the documented behaviour of
synchronize_sched(), it doesn't try to pair synchronize_sched() with
barrier.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is another step towards better standard conformance. Rather than
adding a local buffer to store the specified portion of the string (with
the need to enforce an arbitrary maximum supported width to limit the
buffer size), do a maximum width conversion and then drop as much of it as
is necessary to meet the caller's request.
Also fail on negative field widths.
Uses the deprecated simple_strto*() functions because kstrtoXX() fail on
non-zero terminated strings.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
