Mark Brown [Sun, 9 Oct 2011 12:13:58 +0000 (13:13 +0100)]
regmap: Allow caches for devices with no defaults
We only really need the defaults in order to cut down the number of
registers we sync and to satisfy reads while the device is powered off
but not all devices are going to need to do that (always on devices like
PMICs being the prime example) so don't require those devices to supply
a default. Instead only try to fall back to hardware defaults if the
driver told us to.
Devices using LZO won't be able to instantiate with this, that will require
some updates in the LZO code to handle this case.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Mark Brown [Sun, 9 Oct 2011 11:54:25 +0000 (12:54 +0100)]
regmap: Ensure rbtree syncs registers set to zero properly
Simplify the check for registers set at their default value by avoiding
picking a default value in the case where we don't have one. Instead we
only compare the current value to the current value when we looked one
up. This fixes the case where we don't have a default stored but the value
was set to zero when that isn't the chip default.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Mark Brown [Tue, 4 Oct 2011 21:05:47 +0000 (22:05 +0100)]
regmap: Use bsearch() to search the register defaults
Rather than open coding a binary search use the standard bsearch() using
the comparison function we're already using for sort() on insert. This
fixes a lockup I was observing due to iterating on min <= max rather
than min < max when we fail to look up.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
regmap: Optimize the lookup path to use binary search
Since there are more lookups than insertions in a typical
scenario, optimize the linear search into a binary search. For
this to work, we need to keep reg_defaults sorted upon
insertions, for now be lazy and use sort().
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
In preperation for the upcoming patches, modify map->cache_bypass
directly. The helper functions will grab an exclusive lock. Because
we'll have acquired the same lock we need to avoid a deadlock.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
regmap: rbtree-cache: Move cached rbnode handling into lookup function
Move the handling of the cached rbnode into regcache_rbtree_lookup. This allows
us to remove of some duplicated code sections in regcache_rbtree_read and
regcache_rbtree_write.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
In the absence of a sync callback, do it manually. This of course
can't take advantange of the specific optimizations of each
cache type but it will do well enough in most cases.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Mark Brown [Thu, 15 Sep 2011 16:54:53 +0000 (18:54 +0200)]
mfd: Support software initiated shutdown of WM831x PMICs
In systems where there is no hardware signal from the processor to the
PMIC to initiate the final power off sequence we must initiate the
shutdown with a register write to the PMIC. Support such systems in the
driver. Since this may prevent a full shutdown of the system platform
data is used to enable the feature.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This patch adds support for LZO compression when storing the register
cache.
For a typical device whose register map would normally occupy 25kB or 50kB
by using the LZO compression technique, one can get down to ~5-7kB. There
might be a performance penalty associated with each individual read/write
due to decompressing/compressing the underlying cache, however that should not
be noticeable. These memory benefits depend on whether the target architecture
can get rid of the memory occupied by the original register defaults cache
which is marked as __devinitconst. Nevertheless there will be some memory
gain even if the target architecture can't get rid of the original register
map, this should be around ~30-32kB instead of 50kB.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This patch adds support for the rbtree cache compression type.
Each rbnode manages a variable length block of registers. There can be no
two nodes with overlapping blocks. Each block has a base register and a
currently top register, all the other registers, if any, lie in between these
two and in ascending order.
The reasoning behind the construction of this rbtree is simple. In the
snd_soc_rbtree_cache_init() function, we iterate over the register defaults
provided by the regcache core. For each register value that is non-zero we
insert it in the rbtree. In order to determine in which rbnode we need
to add the register, we first look if there is another register already
added that is adjacent to the one we are about to add. If that is the case
we append it in that rbnode block, otherwise we create a new rbnode
with a single register in its block and add it to the tree.
There are various optimizations across the implementation to speed up lookups
by caching the most recently used rbnode.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> Tested-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This is the simplest form of a cache available in regcache. Any
registers whose default value is 0 are ignored. If any of those
registers are modified in the future, they will be placed in the
cache on demand. The cache layout is essentially using the provided
register defaults by the regcache core directly and does not re-map
it to another representation.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This patch introduces caching support for regmap. The regcache API
has evolved essentially out of ASoC soc-cache so most of the actual
caching types (except LZO) have been tested in the past.
The purpose of regcache is to optimize in time and space the handling
of register caches. Time optimization is achieved by not having to go
over a slow bus like I2C to read the value of a register, instead it is
cached locally in memory and can be retrieved faster. Regarding space
optimization, some of the cache types are better at packing the caches,
for e.g. the rbtree and the LZO caches. By doing this the sacrifice in
time still wins over doing I2C transactions.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> Tested-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Mark Brown [Mon, 5 Sep 2011 18:46:32 +0000 (20:46 +0200)]
regmap: Provide device read and write map interface for merging
Add the externally visible interface introduced by Lars-Peter's commit
6f3064 (regmap: Add support for device specific write and read flag
masks) separately in order to allow merge into other subsystems for
integration with drivers. Drivers relying on this feature will not be
functional until they are merged with the implementation.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Make the debugfs stubs static inline to avoid future compilation issues due to
duplicated symbols when CONFIG_DEBUG_FS=n once internal.h is included by
multiple source files.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
regmap: Add support for device specific write and read flag masks.
Some buses like SPI have no standard notation of read or write operations.
The general scheme here is to set or clear specific bits in the register
address to indicate whether the operation is a read or write. We already
support having a read flag mask per bus, but as there is no standard
the bits which need to be set or cleared differ between devices and vendors,
thus we need a mechanism to specify them per device.
This patch adds two new entries to the regmap_config struct, read_flag_mask and
write_flag_mask. These will be or'ed onto the top byte when doing a read or
write operation. If both masks are empty the device will fallback to the
regmap_bus masks.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Mark Brown [Mon, 5 Sep 2011 15:07:47 +0000 (08:07 -0700)]
regmap: Remove bitrotted module_put()s
The conversion to per bus type registration functions means we don't need
to do module_get()s to hold the bus types in memory (their users will link
to them) so we removed all those calls. This left module_put() calls in
the cleanup paths which aren't needed and which cause unbalanced puts if
we ever try to unload anything.
Reported-by: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Mark Brown [Fri, 10 Jun 2011 18:28:10 +0000 (19:28 +0100)]
mfd: Convert WM831x to use regmap API
Factor out the register read/write code to use the register map API. We
still need some wm831x specific code and locking in place to check that
the user key is handled correctly but only on the write side, reads are
not affected by the key.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Mark Brown [Fri, 19 Aug 2011 09:09:38 +0000 (18:09 +0900)]
regmap: Allow drivers to specify register defaults
It is useful for the register cache code to be able to specify the
default values for the device registers. The major use is when restoring
the register cache after suspend, knowing the register defaults allows
us to skip registers that are at their default values when we resume which
can be a substantial win on larger modern devices. For some devices
(mostly older ones) the hardware does not support readback so the only way we
can know the values is from code and so initializing the cache with default
values makes it much easier for drivers work with read/modify/write
updates.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Mark Brown [Wed, 10 Aug 2011 08:28:04 +0000 (17:28 +0900)]
regmap: Provide access information via debugfs
Let userspace know what the access map for the device is. This is helpful
for verifying that the access map is correctly configured and could also
be useful for programs that try to work with the data. File format is:
register: R W V P
where R, W, V and P are 'y' or 'n' showing readable, writable, volatile
and precious respectively.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Stephen Warren [Thu, 11 Aug 2011 17:59:10 +0000 (11:59 -0600)]
regmap: Specify a module license
CONFIG_REGMAP_I2C/SPI are set to m when selected by a tristate config
option that's set to m. The regmap modules don't specify a license, so
fail to link to regmap_init at load time, since that is EXPORT_SYMBOL_GPL.
Fix this by specifying a license for the regmap modules.
Signed-off-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Mark Brown [Wed, 20 Jul 2011 21:56:53 +0000 (22:56 +0100)]
regmap: Provide register map dump via debugfs
Copy over the read parts of the ASoC debugfs implementation into regmap,
allowing users to see what the register values the device has are at
runtime. The implementation, especially the support for seeking, is
mostly due to Dimitris Papastamos' work in ASoC.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Mark Brown [Sun, 24 Jul 2011 10:46:20 +0000 (11:46 +0100)]
regmap: Implement writable register checks
This is mainly intended to be used by devices which can dynamically
block register writes at runtime, for other devices there is usually
limited value.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Mark Brown [Sun, 24 Jul 2011 20:30:55 +0000 (21:30 +0100)]
regmap: Add basic tracepoints
Trace single register reads and writes, plus start/stop tracepoints for
the actual I/O to see where we're spending time. This makes it easy to
have always on logging without overwhelming the logs and also lets us take
advantage of all the context and time information that the trace subsystem
collects for us.
We don't currently trace register values for bulk operations as this would
add complexity and overhead parsing the cooked data that's being worked
with.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Mark Brown [Wed, 20 Jul 2011 20:47:22 +0000 (21:47 +0100)]
regmap: Just send the buffer directly for single register writes
When doing a single register write we use work_buf for both the register
and the value with the buffer formatted for sending directly to the device
so we can just do a write() directly. This saves allocating a temporary
buffer if we can't do gather writes and is likely to be faster than doing
a gather write.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Mark Brown [Mon, 8 Aug 2011 06:40:22 +0000 (15:40 +0900)]
regmap: Add precious registers to the driver interface
Some devices are sensitive to reads on their registers, especially for
things like clear on read interrupt status registers. Avoid creating
problems with these with things like debugfs by allowing drivers to tell
the core about them. If a register is marked as precious then the core
will not internally generate any reads of it.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Mark Brown [Wed, 20 Jul 2011 21:33:39 +0000 (22:33 +0100)]
regmap: Allow devices to specify which registers are accessible
This is currently unused but we need to know which registers exist and
their properties in order to implement diagnostics like register map
dumps and the cache features.
We use callbacks partly because properties can vary at runtime (eg, through
access locks on registers) and partly because big switch statements are a
good compromise between readable code and small data size for providing
information on big register maps.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Commit d006199e72a9 ("serial: sh-sci: Regtype probing doesn't need to be
fatal.") made sci_init_single() return when sci_probe_regmap() succeeds,
although it should return when sci_probe_regmap() fails. This causes
systems using the serial sh-sci driver to crash during boot.
Fix the problem by using the right return condition.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Sun, 7 Aug 2011 21:07:03 +0000 (14:07 -0700)]
arm: remove "optimized" SHA1 routines
Since commit 1eb19a12bd22 ("lib/sha1: use the git implementation of
SHA-1"), the ARM SHA1 routines no longer work. The reason? They
depended on the larger 320-byte workspace, and now the sha1 workspace is
just 16 words (64 bytes). So the assembly version would overwrite the
stack randomly.
The optimized asm version is also probably slower than the new improved
C version, so there's no reason to keep it around. At least that was
the case in git, where what appears to be the same assembly language
version was removed two years ago because the optimized C BLK_SHA1 code
was faster.
Reported-and-tested-by: Joachim Eastwood <manabian@gmail.com> Cc: Andreas Schwab <schwab@linux-m68k.org> Cc: Nicolas Pitre <nico@fluxnic.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Al Viro [Sun, 7 Aug 2011 17:55:11 +0000 (18:55 +0100)]
fix rcu annotations noise in cred.h
task->cred is declared as __rcu, and access to other tasks' ->cred is,
indeed, protected. Access to current->cred does not need rcu_dereference()
at all, since only the task itself can change its ->cred. sparse, of
course, has no way of knowing that...
Add force-cast in current_cred(), make current_fsuid() et.al. use it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Sun, 7 Aug 2011 16:53:20 +0000 (09:53 -0700)]
vfs: rename 'do_follow_link' to 'should_follow_link'
Al points out that the do_follow_link() helper function really is
misnamed - it's about whether we should try to follow a symlink or not,
not about actually doing the following.
Ari Savolainen [Sat, 6 Aug 2011 16:43:07 +0000 (19:43 +0300)]
Fix POSIX ACL permission check
After commit 3567866bf261: "RCUify freeing acls, let check_acl() go ahead in
RCU mode if acl is cached" posix_acl_permission is being called with an
unsupported flag and the permission check fails. This patch fixes the issue.
Signed-off-by: Ari Savolainen <ari.m.savolainen@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Linus Torvalds [Sun, 7 Aug 2011 05:56:03 +0000 (22:56 -0700)]
Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osd
* 'for-linus' of git://git.open-osd.org/linux-open-osd:
ore: Make ore its own module
exofs: Rename raid engine from exofs/ios.c => ore
exofs: ios: Move to a per inode components & device-table
exofs: Move exofs specific osd operations out of ios.c
exofs: Add offset/length to exofs_get_io_state
exofs: Fix truncate for the raid-groups case
exofs: Small cleanup of exofs_fill_super
exofs: BUG: Avoid sbi realloc
exofs: Remove pnfs-osd private definitions
nfs_xdr: Move nfs4_string definition out of #ifdef CONFIG_NFS_V4
Linus Torvalds [Sun, 7 Aug 2011 05:45:50 +0000 (22:45 -0700)]
vfs: optimize inode cache access patterns
The inode structure layout is largely random, and some of the vfs paths
really do care. The path lookup in particular is already quite D$
intensive, and profiles show that accessing the 'inode->i_op->xyz'
fields is quite costly.
We already optimized the dcache to not unnecessarily load the d_op
structure for members that are often NULL using the DCACHE_OP_xyz bits
in dentry->d_flags, and this does something very similar for the inode
ops that are used during pathname lookup.
It also re-orders the fields so that the fields accessed by 'stat' are
together at the beginning of the inode structure, and roughly in the
order accessed.
The effect of this seems to be in the 1-2% range for an empty kernel
"make -j" run (which is fairly kernel-intensive, mostly in filename
lookup), so it's visible. The numbers are fairly noisy, though, and
likely depend a lot on exact microarchitecture. So there's more tuning
to be done.
Linus Torvalds [Sun, 7 Aug 2011 05:41:50 +0000 (22:41 -0700)]
vfs: renumber DCACHE_xyz flags, remove some stale ones
Gcc tends to generate better code with small integers, including the
DCACHE_xyz flag tests - so move the common ones to be first in the list.
Also just remove the unused DCACHE_INOTIFY_PARENT_WATCHED and
DCACHE_AUTOFS_PENDING values, their users no longer exists in the source
tree.
And add a "unlikely()" to the DCACHE_OP_COMPARE test, since we want the
common case to be a nice straight-line fall-through.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
net: Compute protocol sequence numbers and fragment IDs using MD5.
crypto: Move md5_transform to lib/md5.c
Boaz Harrosh [Sun, 7 Aug 2011 02:26:31 +0000 (19:26 -0700)]
exofs: Rename raid engine from exofs/ios.c => ore
ORE stands for "Objects Raid Engine"
This patch is a mechanical rename of everything that was in ios.c
and its API declaration to an ore.c and an osd_ore.h header. The ore
engine will later be used by the pnfs objects layout driver.
* File ios.c => ore.c
* Declaration of types and API are moved from exofs.h to a new
osd_ore.h
* All used types are prefixed by ore_ from their exofs_ name.
* Shift includes from exofs.h to osd_ore.h so osd_ore.h is
independent, include it from exofs.h.
Other than a pure rename there are no other changes. Next patch
will move the ore into it's own module and will export the API
to be used by exofs and later the layout driver
Boaz Harrosh [Fri, 5 Aug 2011 22:06:04 +0000 (15:06 -0700)]
exofs: ios: Move to a per inode components & device-table
Exofs raid engine was saving on memory space by having a single layout-info,
single pid, and a single device-table, global to the filesystem. Then passing
a credential and object_id info at the io_state level, private for each
inode. It would also devise this contraption of rotating the device table
view for each inode->ino to spread out the device usage.
This is not compatible with the pnfs-objects standard, demanding that
each inode can have it's own layout-info, device-table, and each object
component it's own pid, oid and creds.
So: Bring exofs raid engine to be usable for generic pnfs-objects use by:
* Define an exofs_comp structure that holds obj_id and credential info.
* Break up exofs_layout struct to an exofs_components structure that holds a
possible array of exofs_comp and the array of devices + the size of the
arrays.
* Add a "comps" parameter to get_io_state() that specifies the ids creds
and device array to use for each IO.
This enables to keep the layout global, but the device-table view, creds
and IDs at the inode level. It only adds two 64bit to each inode, since
some of these members already existed in another form.
* ios raid engine now access layout-info and comps-info through the passed
pointers. Everything is pre-prepared by caller for generic access of
these structures and arrays.
At the exofs Level:
* Super block holds an exofs_components struct that holds the device
array, previously in layout. The devices there are in device-table
order. The device-array is twice bigger and repeats the device-table
twice so now each inode's device array can point to a random device
and have a round-robin view of the table, making it compatible to
previous exofs versions.
* Each inode has an exofs_components struct that is initialized at
load time, with it's own view of the device table IDs and creds.
When doing IO this gets passed to the io_state together with the
layout.
While preforming this change. Bugs where found where credentials with the
wrong IDs where used to access the different SB objects (super.c). As well
as some dead code. It was never noticed because the target we use does not
check the credentials.
Boaz Harrosh [Tue, 16 Nov 2010 18:09:58 +0000 (20:09 +0200)]
exofs: Add offset/length to exofs_get_io_state
In future raid code we will need to know the IO offset/length
and if it's a read or write to determine some of the array
sizes we'll need.
So add a new exofs_get_rw_state() API for use when
writeing/reading. All other simple cases are left using the
old way.
The major change to this is that now we need to call
exofs_get_io_state later at inode.c::read_exec and
inode.c::write_exec when we actually know these things. So this
patch is kept separate so I can test things apart from other
changes.
David S. Miller [Thu, 4 Aug 2011 03:50:44 +0000 (20:50 -0700)]
net: Compute protocol sequence numbers and fragment IDs using MD5.
Computers have become a lot faster since we compromised on the
partial MD4 hash which we use currently for performance reasons.
MD5 is a much safer choice, and is inline with both RFC1948 and
other ISS generators (OpenBSD, Solaris, etc.)
Furthermore, only having 24-bits of the sequence number be truly
unpredictable is a very serious limitation. So the periodic
regeneration and 8-bit counter have been removed. We compute and
use a full 32-bit sequence number.
For ipv6, DCCP was found to use a 32-bit truncated initial sequence
number (it needs 43-bits) and that is fixed here as well.
Reported-by: Dan Kaminsky <dan@doxpara.com> Tested-by: Willy Tarreau <w@1wt.eu> Signed-off-by: David S. Miller <davem@davemloft.net>
* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
cifs: cope with negative dentries in cifs_get_root
cifs: convert prefixpath delimiters in cifs_build_path_to_root
CIFS: Fix missing a decrement of inFlight value
cifs: demote DFS referral lookup errors to cFYI
Revert "cifs: advertise the right receive buffer size to the server"
Linus Torvalds [Sat, 6 Aug 2011 19:22:30 +0000 (12:22 -0700)]
Merge branch 'stable/bug.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
* 'stable/bug.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen/trace: Fix compile error when CONFIG_XEN_PRIVILEGED_GUEST is not set
xen: Fix misleading WARN message at xen_release_chunk
xen: Fix printk() format in xen/setup.c
xen/tracing: it looks like we wanted CONFIG_FTRACE
xen/self-balloon: Add dependency on tmem.
xen/balloon: Fix compile errors - missing header files.
xen/grant: Fix compile warning.
xen/pciback: remove duplicated #include
John Stanley [Thu, 4 Aug 2011 00:41:00 +0000 (20:41 -0400)]
savagedb: Fix typo causing regression in savage4 series video chip detection
Two additional savage4 variants were added, but the S3_SAVAGE4_SERIES
macro was incompletely modified, resulting in a false positive detection
of a savage4 card regardless of which savage card is actually present.
For non-savage4 series cards, such as a Savage/IX-MV card, this results
in garbled video and/or a hard-hang at boot time. Fix this by changing
an '||' to an '&&' in the S3_SAVAGE4_SERIES macro.
Signed-off-by: John P. Stanley <jpsinthemix@verizon.net> Reviewed-by: Tormod Volden <debian.tormod@gmail.com>
[ The macros have incomplete parenthesis too, but whatever .. -Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Josh Triplett [Wed, 3 Aug 2011 19:19:07 +0000 (12:19 -0700)]
CodingStyle: Document the exception of not splitting user-visible strings, for grepping
Patch reviewers now recommend not splitting long user-visible strings,
such as printk messages, even if they exceed 80 columns. This avoids
breaking grep. However, that recommendation did not actually appear
anywhere in Documentation/CodingStyle.
See, for example, the thread at
http://news.gmane.org/find-root.php?message_id=%3c1312215262.11635.15.camel%40Joe%2dLaptop%3e
Linus Torvalds [Sat, 6 Aug 2011 18:51:33 +0000 (11:51 -0700)]
vfs: show O_CLOEXE bit properly in /proc/<pid>/fdinfo/<fd> files
The CLOEXE bit is magical, and for performance (and semantic) reasons we
don't actually maintain it in the file descriptor itself, but in a
separate bit array. Which means that when we show f_flags, the CLOEXE
status is shown incorrectly: we show the status not as it is now, but as
it was when the file was opened.
Fix that by looking up the bit properly in the 'fdt->close_on_exec' bit
array.
Uli needs this in order to re-implement the pfiles program:
"For normal file descriptors (not sockets) this was the last piece of
information which wasn't available. This is all part of my 'give
Solaris users no reason to not switch' effort. I intend to offer the
code to the util-linux-ng maintainers."
Linus Torvalds [Sat, 6 Aug 2011 18:43:08 +0000 (11:43 -0700)]
oom_ajd: don't use WARN_ONCE, just use printk_once
WARN_ONCE() is very annoying, in that it shows the stack trace that we
don't care about at all, and also triggers various user-level "kernel
oopsed" logic that we really don't care about. And it's not like the
user can do anything about the applications (sshd) in question, it's a
distro issue.
For ChromiumOS, we use SHA-1 to verify the integrity of the root
filesystem. The speed of the kernel sha-1 implementation has a major
impact on our boot performance.
To improve boot performance, we investigated using the heavily optimized
sha-1 implementation used in git. With the git sha-1 implementation, we
see a 11.7% improvement in boot time.
10 reboots, remove slowest/fastest.
Before:
Mean: 6.58 seconds Stdev: 0.14
After (with git sha-1, this patch):
Mean: 5.89 seconds Stdev: 0.07
The other cool thing about the git SHA-1 implementation is that it only
needs 64 bytes of stack for the workspace while the original kernel
implementation needed 320 bytes.
Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Cc: Ramsay Jones <ramsay@ramsay1.demon.co.uk> Cc: Nicolas Pitre <nico@cam.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: David S. Miller <davem@davemloft.net> Cc: linux-crypto@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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