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<title>user/sven/linux.git/include/linux/raid, branch v4.14.105</title>
<subtitle>Linux Kernel
</subtitle>
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<updated>2017-11-02T10:10:55Z</updated>
<entry>
<title>License cleanup: add SPDX GPL-2.0 license identifier to files with no license</title>
<updated>2017-11-02T10:10:55Z</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2017-11-01T14:07:57Z</published>
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<id>urn:sha1:b24413180f5600bcb3bb70fbed5cf186b60864bd</id>
<content type='text'>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode &amp; Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained &gt;5
   lines of source
 - File already had some variant of a license header in it (even if &lt;5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart &lt;kstewart@linuxfoundation.org&gt;
Reviewed-by: Philippe Ombredanne &lt;pombredanne@nexb.com&gt;
Reviewed-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>md/raid6: implement recovery using ARM NEON intrinsics</title>
<updated>2017-08-09T17:52:07Z</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ard.biesheuvel@linaro.org</email>
</author>
<published>2017-07-13T17:16:01Z</published>
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<id>urn:sha1:6ec4e2514decd6fb4782a9364fa71d6244d05af4</id>
<content type='text'>
Provide a NEON accelerated implementation of the recovery algorithm,
which supersedes the default byte-by-byte one.

Signed-off-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
</entry>
<entry>
<title>lib/raid6: Add log-of-2 table for RAID6 HW requiring disk position</title>
<updated>2017-05-16T04:31:57Z</updated>
<author>
<name>Anup Patel</name>
<email>anup.patel@broadcom.com</email>
</author>
<published>2017-05-15T05:04:52Z</published>
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<id>urn:sha1:b5dceda1f7ef66cba6f8d766502f242a27f96e6d</id>
<content type='text'>
The raid6_gfexp table represents {2}^n values for 0 &lt;= n &lt; 256. The
Linux async_tx framework pass values from raid6_gfexp as coefficients
for each source to prep_dma_pq() callback of DMA channel with PQ
capability. This creates problem for RAID6 offload engines (such as
Broadcom SBA) which take disk position (i.e. log of {2}) instead of
multiplicative cofficients from raid6_gfexp table.

This patch adds raid6_gflog table having log-of-2 value for any given
x such that 0 &lt;= x &lt; 256. For any given disk coefficient x, the
corresponding disk position is given by raid6_gflog[x]. The RAID6
offload engine driver can use this newly added raid6_gflog table to
get disk position from multiplicative coefficient.

Signed-off-by: Anup Patel &lt;anup.patel@broadcom.com&gt;
Reviewed-by: Scott Branden &lt;scott.branden@broadcom.com&gt;
Reviewed-by: Ray Jui &lt;ray.jui@broadcom.com&gt;
Acked-by: Shaohua Li &lt;shli@fb.com&gt;
Signed-off-by: Vinod Koul &lt;vinod.koul@intel.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'md/4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md</title>
<updated>2016-10-07T16:45:43Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-10-07T16:45:43Z</published>
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<id>urn:sha1:c23112e0395a89c8a52cd955442240de7fba46aa</id>
<content type='text'>
Pull MD updates from Shaohua Li:
 "This update includes:

   - new AVX512 instruction based raid6 gen/recovery algorithm

   - a couple of md-cluster related bug fixes

   - fix a potential deadlock

   - set nonrotational bit for raid array with SSD

   - set correct max_hw_sectors for raid5/6, which hopefuly can improve
     performance a little bit

   - other minor fixes"

* tag 'md/4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md:
  md: set rotational bit
  raid6/test/test.c: bug fix: Specify aligned(alignment) attributes to the char arrays
  raid5: handle register_shrinker failure
  raid5: fix to detect failure of register_shrinker
  md: fix a potential deadlock
  md/bitmap: fix wrong cleanup
  raid5: allow arbitrary max_hw_sectors
  lib/raid6: Add AVX512 optimized xor_syndrome functions
  lib/raid6/test/Makefile: Add avx512 gen_syndrome and recovery functions
  lib/raid6: Add AVX512 optimized recovery functions
  lib/raid6: Add AVX512 optimized gen_syndrome functions
  md-cluster: make resync lock also could be interruptted
  md-cluster: introduce dlm_lock_sync_interruptible to fix tasks hang
  md-cluster: convert the completion to wait queue
  md-cluster: protect md_find_rdev_nr_rcu with rcu lock
  md-cluster: clean related infos of cluster
  md: changes for MD_STILL_CLOSED flag
  md-cluster: remove some unnecessary dlm_unlock_sync
  md-cluster: use FORCEUNLOCK in lockres_free
  md-cluster: call md_kick_rdev_from_array once ack failed
</content>
</entry>
<entry>
<title>lib/raid6: Add AVX512 optimized recovery functions</title>
<updated>2016-09-21T16:09:44Z</updated>
<author>
<name>Gayatri Kammela</name>
<email>gayatri.kammela@intel.com</email>
</author>
<published>2016-08-13T01:03:20Z</published>
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<id>urn:sha1:13c520b2993c9faae6770264d33ff1e1ea4c2ceb</id>
<content type='text'>
Optimize RAID6 recovery functions to take advantage of
the 512-bit ZMM integer instructions introduced in AVX512.

AVX512 optimized recovery functions, which is simply based
on recov_avx2.c written by Jim Kukunas

This patch was tested and benchmarked before submission on
a hardware that has AVX512 flags to support such instructions

Cc: Jim Kukunas &lt;james.t.kukunas@linux.intel.com&gt;
Cc: H. Peter Anvin &lt;hpa@zytor.com&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Signed-off-by: Megha Dey &lt;megha.dey@linux.intel.com&gt;
Signed-off-by: Gayatri Kammela &lt;gayatri.kammela@intel.com&gt;
Reviewed-by: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Signed-off-by: Shaohua Li &lt;shli@fb.com&gt;
</content>
</entry>
<entry>
<title>lib/raid6: Add AVX512 optimized gen_syndrome functions</title>
<updated>2016-09-21T16:09:44Z</updated>
<author>
<name>Gayatri Kammela</name>
<email>gayatri.kammela@intel.com</email>
</author>
<published>2016-08-13T01:03:19Z</published>
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<id>urn:sha1:e0a491c1296874a1aca51cc68452f12a4d950029</id>
<content type='text'>
Optimize RAID6 gen_syndrom functions to take advantage of
the 512-bit ZMM integer instructions introduced in AVX512.

AVX512 optimized gen_syndrom functions, which is simply based
on avx2.c written by Yuanhan Liu and sse2.c written by hpa.

The patch was tested and benchmarked before submission on
a hardware that has AVX512 flags to support such instructions

Cc: H. Peter Anvin &lt;hpa@zytor.com&gt;
Cc: Jim Kukunas &lt;james.t.kukunas@linux.intel.com&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Signed-off-by: Megha Dey &lt;megha.dey@linux.intel.com&gt;
Signed-off-by: Gayatri Kammela &lt;gayatri.kammela@intel.com&gt;
Reviewed-by: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Signed-off-by: Shaohua Li &lt;shli@fb.com&gt;
</content>
</entry>
<entry>
<title>RAID/s390: provide raid6 recovery optimization</title>
<updated>2016-09-01T14:13:25Z</updated>
<author>
<name>Martin Schwidefsky</name>
<email>schwidefsky@de.ibm.com</email>
</author>
<published>2016-08-31T07:27:35Z</published>
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<id>urn:sha1:f5b55fa1f81d518925d68b50d2316850c525d1ad</id>
<content type='text'>
The XC instruction can be used to improve the speed of the raid6
recovery. The loops now operate on blocks of 256 bytes.

Signed-off-by: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
</content>
</entry>
<entry>
<title>RAID/s390: add SIMD implementation for raid6 gen/xor</title>
<updated>2016-08-29T09:05:04Z</updated>
<author>
<name>Martin Schwidefsky</name>
<email>schwidefsky@de.ibm.com</email>
</author>
<published>2016-08-23T11:30:24Z</published>
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<id>urn:sha1:474fd6e80fe529e9adeeb7ea9d4e5d6c4da0b7fe</id>
<content type='text'>
Using vector registers is slightly faster:

raid6: vx128x8  gen() 19705 MB/s
raid6: vx128x8  xor() 11886 MB/s
raid6: using algorithm vx128x8 gen() 19705 MB/s
raid6: .... xor() 11886 MB/s, rmw enabled

vs the software algorithms:

raid6: int64x1  gen()  3018 MB/s
raid6: int64x1  xor()  1429 MB/s
raid6: int64x2  gen()  4661 MB/s
raid6: int64x2  xor()  3143 MB/s
raid6: int64x4  gen()  5392 MB/s
raid6: int64x4  xor()  3509 MB/s
raid6: int64x8  gen()  4441 MB/s
raid6: int64x8  xor()  3207 MB/s
raid6: using algorithm int64x4 gen() 5392 MB/s
raid6: .... xor() 3509 MB/s, rmw enabled

Signed-off-by: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
</content>
</entry>
<entry>
<title>raid6/algos.c : bug fix : Add the missing definitions to the pq.h file</title>
<updated>2016-01-21T22:47:08Z</updated>
<author>
<name>Gayatri Kammela</name>
<email>gayatri.kammela@intel.com</email>
</author>
<published>2016-01-21T22:02:39Z</published>
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<id>urn:sha1:6a84f57241e1fb9fb6772256f538d1073359a32d</id>
<content type='text'>
Adding these pr_info and pr_err definitions so as to allow code to be
compiled successfully for testing in userspace, since the printk has
been replaced by pr_info and pr_err in algos.c

Absence of these definitions result in the compilation errors
such as ' undefined reference to `pr_info' ' ' undefined reference to
`pr_err' '

Cc: NeilBrown &lt;neilb@suse.com&gt;
Cc: Anton Blanchard &lt;anton@samba.org&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Signed-off-by: Gayatri Kammela &lt;gayatri.kammela@intel.com&gt;
Signed-off-by: Shaohua Li &lt;shli@fb.com&gt;
</content>
</entry>
<entry>
<title>md/raid6 algorithms: delta syndrome functions</title>
<updated>2015-04-21T22:00:41Z</updated>
<author>
<name>Markus Stockhausen</name>
<email>stockhausen@collogia.de</email>
</author>
<published>2014-12-15T01:57:04Z</published>
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<id>urn:sha1:fe5cbc6e06c7d8b3a86f6f5491d74766bb5c2827</id>
<content type='text'>
v3: s-o-b comment, explanation of performance and descision for
the start/stop implementation

Implementing rmw functionality for RAID6 requires optimized syndrome
calculation. Up to now we can only generate a complete syndrome. The
target P/Q pages are always overwritten. With this patch we provide
a framework for inplace P/Q modification. In the first place simply
fill those functions with NULL values.

xor_syndrome() has two additional parameters: start &amp; stop. These
will indicate the first and last page that are changing during a
rmw run. That makes it possible to avoid several unneccessary loops
and speed up calculation. The caller needs to implement the following
logic to make the functions work.

1) xor_syndrome(disks, start, stop, ...): "Remove" all data of source
blocks inside P/Q between (and including) start and end.

2) modify any block with start &lt;= block &lt;= stop

3) xor_syndrome(disks, start, stop, ...): "Reinsert" all data of
source blocks into P/Q between (and including) start and end.

Pages between start and stop that won't be changed should be filled
with a pointer to the kernel zero page. The reasons for not taking NULL
pages are:

1) Algorithms cross the whole source data line by line. Thus avoid
additional branches.

2) Having a NULL page avoids calculating the XOR P parity but still
need calulation steps for the Q parity. Depending on the algorithm
unrolling that might be only a difference of 2 instructions per loop.

The benchmark numbers of the gen_syndrome() functions are displayed in
the kernel log. Do the same for the xor_syndrome() functions. This
will help to analyze performance problems and give an rough estimate
how well the algorithm works. The choice of the fastest algorithm will
still depend on the gen_syndrome() performance.

With the start/stop page implementation the speed can vary a lot in real
life. E.g. a change of page 0 &amp; page 15 on a stripe will be harder to
compute than the case where page 0 &amp; page 1 are XOR candidates. To be not
to enthusiatic about the expected speeds we will run a worse case test
that simulates a change on the upper half of the stripe. So we do:

1) calculation of P/Q for the upper pages

2) continuation of Q for the lower (empty) pages

Signed-off-by: Markus Stockhausen &lt;stockhausen@collogia.de&gt;
Signed-off-by: NeilBrown &lt;neilb@suse.de&gt;
</content>
</entry>
</feed>
