Another old/known problem. If the tracee is killed after it reports
syscall_entry, it starts the syscall and debugger can't control this.
This confuses the users and this creates the security problems for
ptrace jailers.
Change tracehook_report_syscall_entry() to return non-zero if killed,
this instructs syscall_trace_enter() to abort the syscall.
Reported-by: Chris Evans <scarybeasts@gmail.com>
Tested-by: Indan Zupancic <indan@nul.nu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Pedro Alves <palves@redhat.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since '*outlen' is initialized to zero, it is currently possible to
create a filename of length (FAT_LFN_LEN + 1) when utf8 is not enabled.
To enforce the FAT_LFN_LEN limit, we must perform one less iteration.
Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Ravishankar N <cyberax82@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>
xlate_to_uni() is called by vfat_build_slots() with sbi->nls_io as the
final argument. nls_io can never be null at this point because the
check is already being done in fat_fill_super() wherein the mount fails
if it is null.
Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Ravishankar N <cyberax82@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>
Generalise NVRAM to support RAM with other size and offset, such as the
64 bytes of SRAM on the mcp7941x.
[rdunlap@xenotime.net: fix printk format warning]
Signed-off-by: Austin Boyle <Austin.Boyle@aviatnet.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Cc: David Anders <danders.dev@gmail.com>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Do some cleanup of the comment sections as well as correct some
formatting issues reported by checkpatch.pl.
Signed-off-by: David Anders <x0132446@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Austin Boyle <Austin.Boyle@aviatnet.com>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No need to have two seperate if-blocks for setting up the irq.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Tested-by: David Anders <danders.dev@gmail.com>
Cc: Austin Boyle <Austin.Boyle@aviatnet.com>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The chip_desc table is suboptimal. Currently it requires an entry for
every new chip type, even if it is empty. This has already been
forgotten for the ds1388. Refactor the code, so new entries are only
needed, when they chip type really needs a (non-empty) description.
Also make the table visually more appealing.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Austin Boyle <Austin.Boyle@aviatnet.com>
Cc: David Anders <danders.dev@gmail.com>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
max8925_rtc_read_alarm() should set alrm->enabled based on both
ALARM_IRQ_MASK and ALARM_CTRL setting. max8925_rtc_set_alarm() should
enable/disable alarm according to ALARM_CTRL reg setting.
Signed-off-by: Kevin Liu <kliu5@marvell.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.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>
Since commit e58aa3d2d0 ("genirq: run irq handlers with interrupts
disabled") we run all interrupt handlers with interrupts disabled and we
even check and yell when an interrupt handler returns with interrupts
enabled - see commit b738a50a20 ("genirq: warn when handler enables
interrupts").
So now this flag is a NOOP and can be removed.
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Wan ZongShun <mcuos.com@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Following changes are made as part of this change:
1. As TWL RTC supports periodic interrupt, the correct event should be
RTC_PF instead of RTC_UF.
2. No need to initialize variable "events" to 0 & then OR it with the
event values. Hence fixing it.
Signed-off-by: Venu Byravarasu <vbyravarasu@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>
For clearing RTC interrupt, programming ALARM bit only is sufficient, as
all other bits are any way not affected by writing 0 to them.
Hence removed unwanted OR operation.
Signed-off-by: Venu Byravarasu <vbyravarasu@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>
As part of probe, before enabling RTC, RTC_CTRL register is read to check
if it is already running. If RTC is used by kernel alone, then this read
is not required. Even if RTC was enabled already by boot loader, setting
STOP_RTC bit again should not harm. Hence removed unwanted read
operation.
Signed-off-by: Venu Byravarasu <vbyravarasu@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>
As the TWL RTC driver has a cached copy of enabled RTC interrupt bits in
variable rtc_irq_bits, that can be checked before really setting or
masking any of the interrupt bits.
Signed-off-by: Venu Byravarasu <vbyravarasu@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>
Factor out some boilerplate code for spi driver registration into
module_spi_driver.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Cc: Mark Jackson <mpfj@mimc.co.uk>
Cc: Dennis Aberilla <denzzzhome@yahoo.com>
Cc: Nikolaus Voss <n.voss@weinmann.de>
Cc: "Kim B. Heino" <Kim.Heino@bluegiga.com>
Cc: Raphael Assenat <raph@raphnet.net>
Cc: Chris Verges <chrisv@cyberswitching.com>
Cc: Magnus Damm <damm@opensource.se>
Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
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_device_register() calls rtc-spear routines internally. These
routines call dev_get_drvdata() to get struct spear_rtc_config.
Currently, platform_set_drvdata is called after rtc device is
registered. This causes system to crash, as dev_get_drvdata returns
NULL.
For this we need to call platform_set_drvdata() before registering rtc
device. This requires further cleanup, that leads to removal of
dev_set_drvdata on rtc->dev, which was just not required at all.
Also, we change the parameter to request_irq and pass pointer to config
instead of pointer to rtc struct.
This patch brings all above changes.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Cc: Shiraz Hashim <shiraz.hashim@st.com>
Cc: Deepak Sikri <deepak.sikri@st.com>
Acked-by: Rajeev Kumar <rajeev-dlh.kumar@st.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Define API for '.alarm_irq_enable' to enable and disable alarm irq. This
is required by the framework else RTC_AIE_ON and RTC_AIE_OFF ioctls
return errors.
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Cc: Deepak Sikri <deepak.sikri@st.com>
Acked-by: Rajeev Kumar <rajeev-dlh.kumar@st.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Handle the fix for unbalanced irq for the cases when enable_irq_wake
fails, and a warning related to same is displayed on the console. The
workaround is handled at the driver level.
Signed-off-by: Deepak Sikri <deepak.sikri@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Acked-by: Rajeev Kumar <rajeev-dlh.kumar@st.com>
Cc: Shiraz Hashim <shiraz.hashim@st.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Printing the error code makes it easier to debug the cause of a mount
failure. For example I had the problem that the root file system could
not be mounted read-writeable because my SD card was write-protected.
Without an error code it looks like the SD card was not detected at all.
Signed-off-by: Bernhard Walle <bernhard@bwalle.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Otherwise the 'Calibration skipped' message gets printed everytime a CPU
is hotplugged in, cluttering console for systems that frequently hotplug
CPUs.
Signed-off-by: Diwakar Tundlam <dtundlam@nvidia.com>
Cc: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Greg KH <greg@kroah.com>
Cc: Sameer Nanda <snanda@chromium.org>
Cc: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We never use the length variable.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Looking for a bug in -rt, I stumbled across this code here from: commit
2dfa4eeab0 ("epoll keyed wakeups: teach epoll about hints coming with
the wakeup key"), specifically:
#ifdef CONFIG_DEBUG_LOCK_ALLOC
static inline void ep_wake_up_nested(wait_queue_head_t *wqueue,
unsigned long events, int subclass)
{
unsigned long flags;
spin_lock_irqsave_nested(&wqueue->lock, flags, subclass);
wake_up_locked_poll(wqueue, events);
spin_unlock_irqrestore(&wqueue->lock, flags);
}
#else
static inline void ep_wake_up_nested(wait_queue_head_t *wqueue,
unsigned long events, int subclass)
{
wake_up_poll(wqueue, events);
}
#endif
You change the function of ep_wake_up_nested() depending on whether
CONFIG_DEBUG_LOCK_ALLOC is set or not. This looks awfully suspicious,
and there's no comment to explain why. I initially thought that this
was trying to fool lockdep, and hiding a real bug.
Investigating it, I found the creation of wake_up_nested() (which no
longer exists) but was created for the sole purpose of epoll and its
strange wake ups, as explained in commit 0ccf831cbe ("lockdep:
annotate epoll")
Although the commit message says "annotate epoll" the change log is much
better at explaining what is happening than what is in the actual code.
Thus a comment is really necessary here. And to save the time of other
developers from having to go trudging through the git logs trying to
figure out why this code exists.
I took parts of the change log and placed it into a comment above the
affected code. This will make the description of what is happening more
visible to new developers that have to look at this code for the first
time.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In some cases the poll() implementation in a driver has to do different
things depending on the events the caller wants to poll for. An example
is when a driver needs to start a DMA engine if the caller polls for
POLLIN, but doesn't want to do that if POLLIN is not requested but instead
only POLLOUT or POLLPRI is requested. This is something that can happen
in the video4linux subsystem among others.
Unfortunately, the current epoll/poll/select implementation doesn't
provide that information reliably. The poll_table_struct does have it: it
has a key field with the event mask. But once a poll() call matches one
or more bits of that mask any following poll() calls are passed a NULL
poll_table pointer.
Also, the eventpoll implementation always left the key field at ~0 instead
of using the requested events mask.
This was changed in eventpoll.c so the key field now contains the actual
events that should be polled for as set by the caller.
The solution to the NULL poll_table pointer is to set the qproc field to
NULL in poll_table once poll() matches the events, not the poll_table
pointer itself. That way drivers can obtain the mask through a new
poll_requested_events inline.
The poll_table_struct can still be NULL since some kernel code calls it
internally (netfs_state_poll() in ./drivers/staging/pohmelfs/netfs.h). In
that case poll_requested_events() returns ~0 (i.e. all events).
Very rarely drivers might want to know whether poll_wait will actually
wait. If another earlier file descriptor in the set already matched the
events the caller wanted to wait for, then the kernel will return from the
select() call without waiting. This might be useful information in order
to avoid doing expensive work.
A new helper function poll_does_not_wait() is added that drivers can use
to detect this situation. This is now used in sock_poll_wait() in
include/net/sock.h. This was the only place in the kernel that needed
this information.
Drivers should no longer access any of the poll_table internals, but use
the poll_requested_events() and poll_does_not_wait() access functions
instead. In order to enforce that the poll_table fields are now prepended
with an underscore and a comment was added warning against using them
directly.
This required a change in unix_dgram_poll() in unix/af_unix.c which used
the key field to get the requested events. It's been replaced by a call
to poll_requested_events().
For qproc it was especially important to change its name since the
behavior of that field changes with this patch since this function pointer
can now be NULL when that wasn't possible in the past.
Any driver accessing the qproc or key fields directly will now fail to compile.
Some notes regarding the correctness of this patch: the driver's poll()
function is called with a 'struct poll_table_struct *wait' argument. This
pointer may or may not be NULL, drivers can never rely on it being one or
the other as that depends on whether or not an earlier file descriptor in
the select()'s fdset matched the requested events.
There are only three things a driver can do with the wait argument:
1) obtain the key field:
events = wait ? wait->key : ~0;
This will still work although it should be replaced with the new
poll_requested_events() function (which does exactly the same).
This will now even work better, since wait is no longer set to NULL
unnecessarily.
2) use the qproc callback. This could be deadly since qproc can now be
NULL. Renaming qproc should prevent this from happening. There are no
kernel drivers that actually access this callback directly, BTW.
3) test whether wait == NULL to determine whether poll would return without
waiting. This is no longer sufficient as the correct test is now
wait == NULL || wait->_qproc == NULL.
However, the worst that can happen here is a slight performance hit in
the case where wait != NULL and wait->_qproc == NULL. In that case the
driver will assume that poll_wait() will actually add the fd to the set
of waiting file descriptors. Of course, poll_wait() will not do that
since it tests for wait->_qproc. This will not break anything, though.
There is only one place in the whole kernel where this happens
(sock_poll_wait() in include/net/sock.h) and that code will be replaced
by a call to poll_does_not_wait() in the next patch.
Note that even if wait->_qproc != NULL drivers cannot rely on poll_wait()
actually waiting. The next file descriptor from the set might match the
event mask and thus any possible waits will never happen.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow the kernel builder to choose a crc32* algorithm for the kernel.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add self-test code for crc32c.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since lib/crc32.c now provides crc32c, remove the software implementation
here and call the library function instead.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reuse the existing crc32 code to stamp out a crc32c implementation.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a comment at the top of crc32.c
[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add two changes that improve the performance of x86 systems
1. replace main loop with incrementing counter this change improves
the performance of the selftest by about 5-6% on Nehalem CPUs. The
apparent reason is that the compiler can use the loop index to perform
an indexed memory access. This is reported to make the performance of
PowerPC CPUs to get worse.
2. replace the rem_len loop with incrementing counter this change
improves the performance of the selftest, which has more than the usual
number of occurances, by about 1-2% on x86 CPUs. In actual work loads
the length is most often a multiple of 4 bytes and this code does not
get executed as often if at all. Again this change is reported to make
the performance of PowerPC get worse.
[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add slicing-by-8 algorithm to the existing slicing-by-4 algorithm. This
consists of:
- extend largest BITS size from 32 to 64
- extend tables from tab[4][256] to up to tab[8][256]
- Add code for inner loop.
[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
crc32.c provides a choice of one of several algorithms for computing the
LSB and LSB versions of the CRC32 checksum based on the parameters
CRC_LE_BITS and CRC_BE_BITS.
In the original version the values 1, 2, 4 and 8 respectively selected
versions of the alrogithm that computed the crc 1, 2, 4 and 32 bits as a
time.
This patch series adds a new version that computes the CRC 64 bits at a
time. To make things easier to understand the parameter has been
reinterpreted to actually stand for the number of bits processed in each
step of the algorithm so that the old value 8 has been replaced with the
value 32.
This also allows us to add in a widely used crc algorithm that computes
the crc 8 bits at a time called the Sarwate algorithm.
[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
crc32.c in its original version freely mixed u32, __le32 and __be32 types
which caused warnings from sparse with __CHECK_ENDIAN__. This patch fixes
these by forcing the types to u32.
[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Misc cleanup of lib/crc32.c and related files.
- remove unnecessary header files.
- straighten out some convoluted ifdef's
- rewrite some references to 2 dimensional arrays as 1 dimensional
arrays to make them correct. I.e. replace tab[i] with tab[0][i].
- a few trivial whitespace changes
- fix a warning in gen_crc32tables.c caused by a mismatch in the type of
the pointer passed to output table. Since the table is only used at
kernel compile time, it is simpler to make the table big enough to hold
the largest column size used. One cannot make the column size smaller
in output_table because it has to be used by both the le and be tables
and they can have different column sizes.
[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace the unit test provided in crc32.c, which doesn't have a makefile
and doesn't compile with current headers, with a simpler self test
routine that also gives a measure of performance and runs at module init
time. The self test option can be enabled through a configuration
option CONFIG_CRC32_SELFTEST.
The test stresses the pre and post loops and is thus not very realistic
since actual uses will likely have addresses and lengths that are at
least 4 byte aligned. However, the main loop is long enough so that the
performance is dominated by that loop.
The expected values for crc32_le and crc32_be were generated with the
original version of crc32.c using CRC_BITS_LE = 8 and CRC_BITS_BE = 8.
These values were then used to check all the values of the BITS
parameters in both the original and new versions.
The performance results show some variability from run to run in spite
of attempts to both warm the cache and reduce the amount of OS noise by
limiting interrutps during the test. To get comparable results and to
analyse options wrt performance the best time reported over a small
sample of runs has been taken.
[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move a long comment from lib/crc32.c to Documentation/crc32.txt where it
will more likely get read.
Edited the resulting document to add an explanation of the slicing-by-n
algorithm.
[djwong@us.ibm.com: minor changelog tweaks]
[akpm@linux-foundation.org: fix typo, per George]
Signed-off-by: George Spelvin <linux@horizon.com>
Signed-off-by: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patchset (re)uses Bob Pearson's crc32 slice-by-8 code to stamp out
a software crc32c implementation. It removes the crc32c implementation
in crypto/ in favor of using the stamped-out one in lib/. There is also
a change to Kconfig so that the kernel builder can pick an
implementation best suited for the hardware.
The motivation for this patchset is that I am working on adding full
metadata checksumming to ext4. As far as performance impact of adding
checksumming goes, I see nearly no change with a standard mail server
ffsb simulation. On a test that involves only file creation and
deletion and extent tree writes, I see a drop of about 50 pcercent with
the current kernel crc32c implementation; this improves to a drop of
about 20 percent with the enclosed crc32c code.
When metadata is usually a small fraction of total IO, this new
implementation doesn't help much because metadata is usually a small
fraction of total IO. However, when we are doing IO that is almost all
metadata (such as rm -rf'ing a tree), then this patch speeds up the
operation substantially.
Incidentally, given that iscsi, sctp, and btrfs also use crc32c, this
patchset should improve their speed as well. I have not yet quantified
that, however. This latest submission combines Bob's patches from late
August 2011 with mine so that they can be one coherent patch set.
Please excuse my inability to combine some of the patches; I've been
advised to leave Bob's patches alone and build atop them instead. :/
Since the last posting, I've also collected some crc32c test results on
a bunch of different x86/powerpc/sparc platforms. The results can be
viewed here: http://goo.gl/sgt3i ; the "crc32-kern-le" and "crc32c"
columns describe the performance of the kernel's current crc32 and
crc32c software implementations. The "crc32c-by8-le" column shows
crc32c performance with this patchset applied. I expect crc32
performance to be roughly the same.
The two _boost columns at the right side of the spreadsheet shows how much
faster the new implementation is over the old one. As you can see, crc32
rises substantially, and crc32c experiences a huge increase.
This patch:
- remove trailing whitespace from lib/crc32.c
- remove trailing whitespace from lib/crc32defs.h
[djwong@us.ibm.com: changelog tweaks]
Signed-off-by: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch already makes an exception to the 80-column rule for quoted
strings, and Documentation/CodingStyle recommends not splitting quoted
strings across lines, because it breaks the ability to grep for the
string. Rather than just permitting this, actively warn about quoted
strings split across lines.
Test case:
void context(void)
{
struct { unsigned magic; const char *strdata; } foo[] = {
{ 42, "these strings"
"do not produce warnings" },
{ 256, "though perhaps"
"they should" },
};
pr_err("this string"
" should produce a warning\n");
pr_err("this multi-line string\n"
"should not produce a warning\n");
asm ("this asm\n\t"
"should not produce a warning");
}
Results of checkpatch on that test case:
WARNING: quoted string split across lines
+ " should produce a warning\n");
total: 0 errors, 1 warnings, 15 lines checked
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Acked-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>
Add blank lines between a few tests, remove an extraneous one.
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>
Using yield() is generally wrong. Warn on its use.
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add some more subjective --strict tests.
Add a test for block comments that start with a blank line followed only
by a line with just the comment block initiator. Prefer a blank line
followed by /* comment...
Add a test for unnecessary spaces after a cast.
Add a test for symmetric uses of braces in if/else blocks.
If one branch needs braces, then all branches should use braces.
Signed-off-by: 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>
Add [] to a type extensions. Fixes false positives on:
.attrs = (struct attribute *[]) {
Signed-off-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>
With any very high precedence operator it is not necessary to enforce
additional parentheses around simple negated expressions. This prevents
us requesting further perentheses around the following:
#define PMEM_IS_FREE(id, index) !(pmem[id].bitmap[index].allocated)
For now add logical and bitwise not and unary minus.
Signed-off-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>
Adjacent strings indicate concatentation, therefore look at identifiers
directly adjacent to literal strings as strings too. This allows us to
better detect the form below and accept it as a simple constant:
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
Signed-off-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>
Fix checkpatch.pl when both -q and --ignore are given and prevents it from
printing a
NOTE: Ignored message types: blah
messages.
E.g., if I use -q --ignore PREFER_PACKED,PREFER_ALIGNED, i see:
NOTE: Ignored message types: PREFER_ALIGNED PREFER_PACKED
It makes no sense to print this when -q is given.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
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>
Oleg Nesterov
Namjae Jeon
Austin Boyle
David Anders
Wolfram Sang
Ashish Jangam
Kevin Liu
Navin P
Yong Zhang
Venu Byravarasu
zhao zhang
Axel Lin
Viresh Kumar
Shiraz Hashim
Deepak Sikri
Bernhard Walle
Diwakar Tundlam
Dan Carpenter
Steven Rostedt
Hans Verkuil
Darrick J. Wong
Bob Pearson
Josh Triplett
Joe Perches
Andy Whitcroft
Artem Bityutskiy