[media] staging: as102: Remove redundant NULL check before release_firmware() and pointless comments
release_firmware() deals gracefullt with NULL pointers - it's
redundant to check for them before calling the function.
Also remove a few pointless comments - it's rather obvious from the
code that kfree() free's a buffer and that release_firmware() releases
firmware - comments just stating that add no value.
Xi Wang [Fri, 6 Apr 2012 12:32:37 +0000 (09:32 -0300)]
[media] v4l2-ctrls: fix integer overflow in try_set_ext_ctrls()
A large cs->count from userspace may overflow the allocation size,
leading to memory corruption. try_set_ext_ctrls() can be reached
from subdev_do_ioctl() or __video_do_ioctl().
Use kmalloc_array() to avoid the overflow.
Signed-off-by: Xi Wang <xi.wang@gmail.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Xi Wang [Fri, 6 Apr 2012 12:32:36 +0000 (09:32 -0300)]
[media] v4l2-ctrls: fix integer overflow in v4l2_g_ext_ctrls()
A large cs->count from userspace may overflow the allocation size,
leading to memory corruption. v4l2_g_ext_ctrls() can be reached
from subdev_do_ioctl() or __video_do_ioctl().
Use kmalloc_array() to avoid the overflow.
Signed-off-by: Xi Wang <xi.wang@gmail.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
kfifo_avail expands to __kfifo_max_r which is not an exported symbol.
Any kernel module using kfifo_avail will result in build failures
because of this.
This patch just exports __kfifo_max_r symbol to fix such problems in
future.
Alan McIvor [Mon, 2 Apr 2012 00:11:08 +0000 (21:11 -0300)]
[media] Default bt878 contrast value
The default_value for the Bt878 V4L2_CID_CONTRAST control is currently
set to 32768. Internally this gets translated to an analog input
circuit gain of 1.19. However, the default gain should be 1.0. This
patch alters the default value to 27648 which corresponds to a gain of
1.0. It also alters the probe routine so that the correct value is
written on board initialisation.
[mchehab@redhat.com: behavior confirmed via Fusion 878a datasheet] Signed-off-by: Alan McIvor <alan.mcivor@reveal.co.nz> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
[media] ati_remote: add support for Medion X10 Digitainer remote
Add support for another Medion X10 remote. This was apparently
originally used with the Medion Digitainer box, but is now sold
separately without any Digitainer labeling.
A peculiarity of this remote is a scrollwheel in place of up/down
buttons. Each direction is mapped to 8 different scancodes, each
corresponding to 1..8 notches, allowing multiple notches to the same
direction to be transmitted in a single scancode. The driver transforms
the multi-notch scancodes to multiple events of the single-notch
scancode.
(0x70..0x77 = 1..8 notches down, 0x78..0x7f = 1..8 notches up)
Since the scrollwheel scancodes are the same that are used for mouse on
some other X10 (ati_remote) remotes, the driver will now check whether
the active keymap has a keycode defined for the single-notch scancode
when a mouse/scrollwheel scancode (0x70..0x7f) is received. If set,
scrollwheel is assumed, otherwise mouse is assumed.
This remote ships with a different receiver than the already supported
Medion X10 remote, but they share the same USB ID. The only difference
in the USB descriptors is that the Digitainer receiver has the Remote
Wakeup bit set in bmAttributes of the Configuration Descriptor.
Therefore that is used to select the default keymap.
Thanks to Stephan Raue from OpenELEC (www.openelec.tv) for providing me
both a Medion X10 Digitainer remote+receiver and an already supported
Medion X10 remote+receiver. Thanks to Martin Beyss for providing some
useful information about the remote (including the "Digitainer" name).
This patch has been tested by both of them and myself.
Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi> Tested-by: Stephan Raue <stephan@openelec.tv> Tested-by: Martin Beyss <Martin.Beyss@rwth-aachen.de> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Uwe Kleine-König [Fri, 30 Mar 2012 19:05:03 +0000 (16:05 -0300)]
[media] s5p-tv: mark const init data with __initconst instead of __initdata
As long as there is no other non-const variable marked __initdata in the
same compilation unit it doesn't hurt. If there were one however
compilation would fail with
error: $variablename causes a section type conflict
because a section containing const variables is marked read only and so
cannot contain non-const variables.
Ezequiel García [Mon, 26 Mar 2012 12:13:34 +0000 (09:13 -0300)]
[media] em28xx: Change scope of em28xx-input local functions to static
This functions are no longer used from another file,
so they should be declared as static.
Also is it necessary to move some of them before they
are used, since they are no longer header-declared.
Jesper Juhl [Sat, 24 Mar 2012 21:39:18 +0000 (18:39 -0300)]
[media] staging/media/as102: Don't call release_firmware() on uninitialized variable
If, in drivers/staging/media/as102/as102_fw.c::as102_fw_upload(), the call
cmd_buf = kzalloc(MAX_FW_PKT_SIZE, GFP_KERNEL);
should fail and return NULL so that we jump to the 'error:' label,
then we'll end up calling 'release_firmware(firmware);' with
'firmware' still uninitialized - not good.
The easy fix is to just initialize 'firmware' to NULL when we declare
it, since release_firmware() deals gracefully with being passed NULL
pointers.
Bhupesh Sharma [Thu, 22 Mar 2012 03:50:37 +0000 (00:50 -0300)]
[media] usb: gadget/uvc: Remove non-required locking from 'uvc_queue_next_buffer' routine
This patch removes the non-required spinlock acquire/release calls on
'queue_irqlock' from 'uvc_queue_next_buffer' routine.
This routine is called from 'video->encode' function (which translates to either
'uvc_video_encode_bulk' or 'uvc_video_encode_isoc') in 'uvc_video.c'.
As, the 'video->encode' routines are called with 'queue_irqlock' already held,
so acquiring a 'queue_irqlock' again in 'uvc_queue_next_buffer' routine causes
a spin lock recursion.
copy_in_user() already checks for write permission, so we don't need to
do it here. This was added in 1a5e4c867c "[media] uvcvideo: Implement
compat_ioctl32 for custom ioctls".
[media] [3.3.0] ir-raw: remove BUG_ON in ir_raw_event_thread
This patch removes BUG_ON in ir_raw_event_thread which IMO is a
over-kill, and this kills the ir_raw_event_thread too. With a bit of
additional logic in this patch, we nomore need to kill this thread.
Other disadvantage of having a BUG-ON is,
wake_up_process(dev->raw->thread) called on dead thread via
ir_raw_event_handle will result in total lockup in SMP system.
Advantage of this patch is ir-raw event thread is left in a usable state
even if the fifo does not have enough bytes.
This patch sets the thread into TASK_INTERRUPTIBLE if raw-fifo has less
then sizeof(struct ir_raw_event) bytes.
Javier Martin [Tue, 20 Mar 2012 14:33:59 +0000 (11:33 -0300)]
[media] i.MX2: eMMa-PrP: Allow userptr IO mode
Userptr can be very useful if this device
is requested to use video buffers allocated
by another processing device. So that
buffers don't need to be copied.
Signed-off-by: Javier Martin <javier.martin@vista-silicon.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Gianluca Gennari [Tue, 20 Mar 2012 13:10:39 +0000 (10:10 -0300)]
[media] lirc: delete unused init/exit function prototypes
The lirc sasem and imon drivers now use the module_usb_driver macro, so the old
init/exit function prototypes are useless.
This patch eliminates this warnings:
media_build/v4l/lirc_imon.c:74:19: warning: 'imon_init' declared 'static' but never defined [-Wunused-function]
media_build/v4l/lirc_imon.c:75:20: warning: 'imon_exit' declared 'static' but never defined [-Wunused-function]
media_build/v4l/lirc_sasem.c:84:19: warning: 'sasem_init' declared 'static' but never defined [-Wunused-function]
media_build/v4l/lirc_sasem.c:85:20: warning: 'sasem_exit' declared 'static' but never defined [-Wunused-function]
[media] s5p-fimc: Handle sub-device interdependencies using deferred probing
In this driver there are several entities associated with separate
platform or I2C client devices, which may get probed in random order.
When the platform device bound to the media device driver is probed
all other entity drivers need to be already in place and initialized.
If any of them is not, fail the media device probe and return an error
indicating we need to be retried once any new driver gets registered.
The media device driver probe will not succeed until there are available
all needed sub-drivers, as specified in the platform data.
While at it, make sure the s5p-csis module (MIPI-CSI receiver driver)
does not get unloaded when in use, by guarding its usage with
try_module_get/module_put.
This patch is a prerequisite for adding the device tree support.
It now also allows again to unbind/bind the driver at runtime from
user space via sysfs.
[media] s5p-fimc: Reinitialize the pipeline properly after VIDIOC_STREAMOFF
This patch prevents blocking on DQBUF at a video capture node in some
conditions, after STREAOMOFF/STREAMON sequence. The ST_CAPT_SUSPEND
flag should not be set during normal stream off, otherwise the
capture engine is not properly enabled at stream on.
Reported-by: Bernard Debbasch <b.debbasch@ssi.samsung.com> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
[media] s5p-fimc: Don't use platform data for CSI data alignment configuration
The MIPI-CSI2 data alignment parameter can be derived from media bus
pixel code, so it can be now dropped from the platform data structure.
This is a prerequisite for adding the device tree support. Once this
patch is merged the corresponding fields will be removed from the
drivers' public headers and corresponding board files.
Sakari Ailus [Fri, 14 Oct 2011 17:14:26 +0000 (14:14 -0300)]
[media] v4l: VIDIOC_SUBDEV_S_SELECTION and VIDIOC_SUBDEV_G_SELECTION IOCTLs
Add support for VIDIOC_SUBDEV_S_SELECTION and VIDIOC_SUBDEV_G_SELECTION
IOCTLs. They replace functionality provided by VIDIOC_SUBDEV_S_CROP and
VIDIOC_SUBDEV_G_CROP IOCTLs and also add new functionality (composing).
VIDIOC_SUBDEV_G_CROP and VIDIOC_SUBDEV_S_CROP continue to be supported.
Sakari Ailus [Thu, 4 Aug 2011 16:51:11 +0000 (13:51 -0300)]
[media] v4l: Introduce integer menu controls
Create a new control type called V4L2_CTRL_TYPE_INTEGER_MENU. Integer menu
controls are just like menu controls but the menu items are 64-bit integers
rather than strings.
Antti Palosaari [Fri, 6 Apr 2012 10:09:23 +0000 (07:09 -0300)]
[media] af9035: disable frontend0 I2C-gate control
Seems like tuners used for frontend0 are not behind demodulator
I2C-gate thus gate control is not needed. Disable it for sure as
it can cause problems some situations.
Signed-off-by: Antti Palosaari <crope@iki.fi> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Antti Palosaari [Fri, 6 Apr 2012 00:58:09 +0000 (21:58 -0300)]
[media] af9035: reorganise USB ID and device list
Add and rename "Afatech AF9035 reference design" as a first
device in the list since it sounds logical to keep reference
design IDs on top of the list.
Signed-off-by: Antti Palosaari <crope@iki.fi> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Antti Palosaari [Thu, 5 Apr 2012 23:28:51 +0000 (20:28 -0300)]
[media] af9035: initial support for IT9135 chip
AF9035 code needed for IT9135 chip support. Needs still small
changes for AF9033 and totally new tuner driver in order to
get that chip version working.
Signed-off-by: Antti Palosaari <crope@iki.fi> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Antti Palosaari [Mon, 2 Apr 2012 23:18:59 +0000 (20:18 -0300)]
[media] af9035: fix and enhance I2C adapter
There was a bug I2C adapter writes and reads one byte too much.
As the most I2C clients has auto-increment register addressing
this leads next register from the target register overwritten by
garbage data.
As a change remove whole register address byte usage and write
data directly to the I2C bus without saying what are register
address bytes to firmware.
Signed-off-by: Antti Palosaari <crope@iki.fi> Cc: Michael Buesch <m@bues.ch> Cc: Hans-Frieder Vogt <hfvogt@gmx.net> Cc: Gianluca Gennari <gennarone@gmail.com> Tested-by: Michael Buesch <m@bues.ch> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
af9035.c: In function 'af9035_download_firmware':
af9035.c:446:3: warning: format '%lu' expects argument of type 'long unsigned
int', but argument 3 has type 'unsigned int' [-Wformat]
%zu avoids any warning on both 32 and 64 bit systems.
Michael Büsch [Sun, 1 Apr 2012 19:33:48 +0000 (16:33 -0300)]
[media] af9035: Add USB read checksumming
This adds USB message read checksumming to protect against
device and bus errors.
It also adds a read length check to avoid returning garbage from
the buffer, if the device truncated the message.
Signed-off-by: Michael Buesch <m@bues.ch> Signed-off-by: Antti Palosaari <crope@iki.fi> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Hans de Goede [Sun, 9 Oct 2011 13:28:27 +0000 (10:28 -0300)]
[media] pwc: poll(): Check that the device has not beem claimed for streaming already
Some apps which use read() start the streaming through a call to poll(),
this means that if another app has already claimed the device for streaming
(through for example a s_fmt, or a reqbufs), that the poll should fail instead
of getting passed through to vb2_poll.
We only check for this when the app is polling for reads, so that ctrl events
still work.
Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Hans Verkuil [Wed, 13 Jul 2011 07:28:27 +0000 (04:28 -0300)]
[media] vivi: let vb2_poll handle events
The vb2_poll function now tests for events and sets POLLPRI accordingly.
So there it is no longer necessary to test for it in the vivi driver.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Hans Verkuil [Wed, 13 Jul 2011 07:03:52 +0000 (04:03 -0300)]
[media] videobuf: only start streaming in poll() if so requested by the poll mask
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Hans Verkuil [Fri, 3 Feb 2012 08:12:18 +0000 (05:12 -0300)]
[media] ivtv: only start streaming in poll() if polling for input
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Andy Walls <awalls@md.metrocast.net> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
* poll: (5970 commits)
poll: add poll_requested_events() and poll_does_not_wait() functions
crc32: select an algorithm via Kconfig
crc32: add self-test code for crc32c
crypto: crc32c should use library implementation
crc32: bolt on crc32c
crc32: add note about this patchset to crc32.c
crc32: optimize loop counter for x86
crc32: add slice-by-8 algorithm to existing code
crc32: make CRC_*_BITS definition correspond to actual bit counts
crc32: fix mixing of endian-specific types
crc32: miscellaneous cleanups
crc32: simplify unit test code
crc32: move long comment about crc32 fundamentals to Documentation/
crc32: remove two instances of trailing whitespaces
checkpatch: check for quoted strings broken across lines
checkpatch: whitespace - add/remove blank lines
checkpatch: warn on use of yield()
checkpatch: add --strict tests for braces, comments and casts
checkpatch: add [] to type extensions
checkpatch: high precedence operators do not require additional parentheses in #defines
...
Hans Verkuil [Fri, 23 Mar 2012 22:02:27 +0000 (15:02 -0700)]
poll: add poll_requested_events() and poll_does_not_wait() functions
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>
Darrick J. Wong [Fri, 23 Mar 2012 22:02:26 +0000 (15:02 -0700)]
crc32: select an algorithm via Kconfig
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>
Darrick J. Wong [Fri, 23 Mar 2012 22:02:26 +0000 (15:02 -0700)]
crc32: add self-test code for crc32c
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>
Darrick J. Wong [Fri, 23 Mar 2012 22:02:25 +0000 (15:02 -0700)]
crypto: crc32c should use library implementation
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>
Darrick J. Wong [Fri, 23 Mar 2012 22:02:25 +0000 (15:02 -0700)]
crc32: bolt on crc32c
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>
Bob Pearson [Fri, 23 Mar 2012 22:02:24 +0000 (15:02 -0700)]
crc32: add note about this patchset to crc32.c
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>
Bob Pearson [Fri, 23 Mar 2012 22:02:24 +0000 (15:02 -0700)]
crc32: optimize loop counter for x86
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>
Bob Pearson [Fri, 23 Mar 2012 22:02:24 +0000 (15:02 -0700)]
crc32: add slice-by-8 algorithm to existing code
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>
Bob Pearson [Fri, 23 Mar 2012 22:02:23 +0000 (15:02 -0700)]
crc32: make CRC_*_BITS definition correspond to actual bit counts
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>
Bob Pearson [Fri, 23 Mar 2012 22:02:23 +0000 (15:02 -0700)]
crc32: fix mixing of endian-specific types
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>
Bob Pearson [Fri, 23 Mar 2012 22:02:22 +0000 (15:02 -0700)]
crc32: miscellaneous cleanups
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>
Bob Pearson [Fri, 23 Mar 2012 22:02:22 +0000 (15:02 -0700)]
crc32: simplify unit test code
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>
Bob Pearson [Fri, 23 Mar 2012 22:02:22 +0000 (15:02 -0700)]
crc32: move long comment about crc32 fundamentals to Documentation/
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>
Bob Pearson [Fri, 23 Mar 2012 22:02:21 +0000 (15:02 -0700)]
crc32: remove two instances of trailing whitespaces
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>
Josh Triplett [Fri, 23 Mar 2012 22:02:21 +0000 (15:02 -0700)]
checkpatch: check for quoted strings broken across lines
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>
Joe Perches [Fri, 23 Mar 2012 22:02:20 +0000 (15:02 -0700)]
checkpatch: warn on use of yield()
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>
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