- 23 Mar, 2012 40 commits
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Darrick J. Wong authored
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>
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Bob Pearson authored
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:
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Bob Pearson authored
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:
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Bob Pearson authored
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:
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Bob Pearson authored
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:
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Bob Pearson authored
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:
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Bob Pearson authored
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:
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Bob Pearson authored
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:
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Bob Pearson authored
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:
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Bob Pearson authored
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:
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Josh Triplett authored
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:
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Joe Perches authored
Add blank lines between a few tests, remove an extraneous one. Signed-off-by:
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Joe Perches authored
Using yield() is generally wrong. Warn on its use. Signed-off-by:
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Joe Perches authored
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:
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Andy Whitcroft authored
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:
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Andy Whitcroft authored
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 authored
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 authored
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Andy Whitcroft authored
Handle the [ A ... B ] form deeper into a definition, for example: static const unsigned char pci_irq_swizzle[2][PCI_MAX_DEVICES] = { {0, 0, 0, 0, 0, 0, 0, 27, 27, [9 ... PCI_MAX_DEVICES - 1] = 0 }, {0, 0, 0, 0, 0, 0, 0, 29, 29, [9 ... PCI_MAX_DEVICES - 1] = 0 }, }; Reported-by:Marek Vasut <marek.vasut@gmail.com> Signed-off-by:
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Artem Bityutskiy authored
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:
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Joe Perches authored
Argument alignment across multiple lines should match the open parenthesis. Logical continuations should be at the end of the previous line, not the start of a new line. These are not required by CodingStyle so make the tests active only when using --strict. Improved by some examples from Bruce Allen. Signed-off-by:
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Joe Perches authored
It's equivalent to __printf, so prefer __scanf. Signed-off-by:
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Xiao Guangrong authored
Introduce prio_set_parent() to abstract the operation which is used to attach the node to its parent. Signed-off-by:
Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by:
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Xiao Guangrong authored
In current code, the deleted-node is recorded from first to last, actually, we can directly attach these node on 'node' we will insert as the left child, it can let the code more readable. Signed-off-by:
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Xiao Guangrong authored
Introduce iter_walk_down()/iter_walk_up() to remove the common code between prio_tree_left() and prio_tree_right(). Signed-off-by:
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Xiao Guangrong authored
Remove the code since 'node' has already been initialized in the begin of the function Signed-off-by:
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Akinobu Mita authored
- Generate a 64-bit pattern more efficiently memchr_inv needs to generate a 64-bit pattern filled with a target character. The operation can be done by more efficient way. - Don't call the slow check_bytes() if the memory area is 64-bit aligned memchr_inv compares contiguous 64-bit words with the 64-bit pattern as much as possible. The outside of the region is checked by check_bytes() that scans for each byte. Unfortunately, the first 64-bit word is unexpectedly scanned by check_bytes() even if the memory area is aligned to a 64-bit boundary. Both changes were originally suggested by Eric Dumazet. Signed-off-by:
Akinobu Mita <akinobu.mita@gmail.com> Suggested-by:
Eric Dumazet <eric.dumazet@gmail.com> Cc: Brian Norris <computersforpeace@gmail.com> Signed-off-by:
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Bryan Wu authored
After moving some core functions to led-core.c, led-class.c can be built as module again. Signed-off-by:
Bryan Wu <bryan.wu@canonical.com> Acked-by:
Richard Purdie <richard.purdie@linuxfoundation.org> Acked-by:
Linus Walleij <linus.walleij@linaro.org> Signed-off-by:
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Axel Lin authored
Improve the readability by moving the code setting gen_config to one place. [akpm@linux-foundation.org: fix some patch skew] Signed-off-by:
Axel Lin <axel.lin@gmail.com> Cc: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com> Cc: "Milo(Woogyom) Kim" <milo.kim@ti.com> Cc: Richard Purdie <rpurdie@rpsys.net> Acked-by:
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Axel Lin authored
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Kim, Milo authored
Use 'pdata' rather than 'pltfm' in lm3530_init_registers(). Signed-off-by:
Milo(Woogyom) Kim <milo.kim@ti.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Axel Lin <axel.lin@gmail.com> Signed-off-by:
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Kim, Milo authored
LM3530_ALS_ZONE_REG is read-only register. Writing this register is not necessary. Signed-off-by:
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Kim, Milo authored
* add 'struct lm3530_pwm_data' in the platform data The pwm data is the platform specific functions which generate the pwm. The pwm data is only valid when brightness is pwm input mode. Functions should be implemented by the pwm driver. pwm_set_intensity() : set duty of pwm. pwm_get_intensity() : get current the brightness. * brightness control by pwm If the control mode is pwm, then brightness is changed by the duty of pwm=. So pwm platform function should be called in lm3530_brightness_set(). * do not update brightness register when pwm input mode In pwm input mode, brightness register is not used. If any value is updated in this register, then the led will be off. * when input mode is changed, set duty of pwm to 0 if unnecessary. Signed-off-by:
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Kim, Milo authored
To get members of lm3530_data, use 'struct led_classdev' rather than 'struct i2c_client'. [akpm@linux-foundation.org: fix 80-column fixes more nicely] Signed-off-by:
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Kim, Milo authored
Only 7 bits are used for updating the brightness. (register address : A0h) So the max_brightness property of lm3530 should be set to 127. On initializing registers, maximum initial brightness is limited to 'max_brightness'. Division-by-two is removed on updating the brightness. This arithmetic is not necessary because the range of brightness is 0 ~ 127= . Signed-off-by:
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Mark Brown authored
Direct usage of the asm include has long been deprecated by the introduction of gpiolib. Signed-off-by:
Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by:
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Peter Meerwald authored
Driver for the PCA9633 I2C chip supporting four LEDs and 255 brightness levels. [akpm@linux-foundation.org: fix kcalloc() call] [axel.lin@gmail.com: fix kcalloc parameters swapped] Signed-off-by:
Peter Meerwald <p.meerwald@bct-electronic.com> Signed-off-by:
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Andrew Morton authored
Saves ~50 bytes text and speeds things up. Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by:
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Srinidhi KASAGAR authored
Fix it by assigning the lp5521_read return value. Signed-off-by:
srinidhi kasagar <srinidhi.kasagar@stericsson.com> Cc: Milo(Woogyom) Kim <milo.kim@ti.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Arun MURTHY <arun.murthy@stericsson.com> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by:
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Kim, Milo authored
For better readability, values of LP5521_REG_ENABLE register were redefined= . Additional definitions: LP5521_ENABLE_DEFAULT and LP5521_ENABLE_RUN_PROGRAM= . Use definition rather than hard code value. : 0x3F -> 'LP5521_CMD_DIRECT' Signed-off-by:
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