linux-toradex.git/lib/crc32.c, branch v4.4.93

lib: crc32: Add some additional __pure annotations

2014-06-25T23:04:00+00:00

In case they help the compiler.

Signed-off-by: George Spelvin 
Signed-off-by: Daniel Borkmann 
Signed-off-by: David S. Miller

lib: crc32: Mark test data __initconst

2014-06-25T23:03:59+00:00

So it gets discarded after the selftest.

Signed-off-by: George Spelvin 
Signed-off-by: Daniel Borkmann 
Signed-off-by: David S. Miller

lib: crc32: Greatly shrink CRC combining code

2014-06-25T23:03:59+00:00

There's no need for a full 32x32 matrix, when rows before the last are
just shifted copies of the rows after them.

There's still room for improvement (especially on X86 processors with
CRC32 and PCLMUL instructions), but this is a large step in the
right direction [which is in particular useful for its current user,
namely SCTP checksumming over multiple skb frags[] entries, i.e. in
IPVS balancing when other CRC32 offloads are not available].

The internal primitive is now called crc32_generic_shift and takes one
less argument; the XOR with crc2 is done in inline wrappers.

Signed-off-by: George Spelvin 
Signed-off-by: Daniel Borkmann 
Signed-off-by: David S. Miller

lib/crc32.c: remove unnecessary __constant

2014-06-04T23:54:19+00:00

Use cpu_to_le32 instead of __constant_cpu_to_le32.

Signed-off-by: Fabian Frederick 
Cc: "David S. Miller" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib: crc32: reduce number of cases for crc32{, c}_combine

2013-11-04T20:27:08+00:00

We can safely reduce the number of test cases by a tenth.
There is no particular need to run as many as we're running
now for crc32{,c}_combine, that gives us still ~8000 tests
we're doing if people run kernels with crc selftests enabled
which is perfectly fine.

Signed-off-by: Daniel Borkmann 
Signed-off-by: David S. Miller

lib: crc32: conditionally resched when running testcases

2013-11-04T20:27:08+00:00

Fengguang reports that when crc32 selftests are running on startup, on
some e.g. 32bit systems, we can get a CPU stall like "INFO: rcu_sched
self-detected stall on CPU { 0} (t=2101 jiffies g=4294967081 c=4294967080
q=41)". As this is not intended, add a cond_resched() at the end of a
test case to fix it. Introduced by efba721f63 ("lib: crc32: add test cases
for crc32{, c}_combine routines").

Reported-by: Fengguang Wu 
Signed-off-by: Daniel Borkmann 
Signed-off-by: David S. Miller

lib: crc32: add test cases for crc32{, c}_combine routines

2013-11-04T04:04:56+00:00

We already have 100 test cases for crcs itself, so split the test
buffer with a-prio known checksums, and test crc of two blocks
against crc of the whole block for the same results.

Output/result with CONFIG_CRC32_SELFTEST=y:

  [    2.687095] crc32: CRC_LE_BITS = 64, CRC_BE BITS = 64
  [    2.687097] crc32: self tests passed, processed 225944 bytes in 278177 nsec
  [    2.687383] crc32c: CRC_LE_BITS = 64
  [    2.687385] crc32c: self tests passed, processed 225944 bytes in 141708 nsec
  [    7.336771] crc32_combine: 113072 self tests passed
  [   12.050479] crc32c_combine: 113072 self tests passed
  [   17.633089] alg: No test for crc32 (crc32-pclmul)

Signed-off-by: Daniel Borkmann 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller

lib: crc32: add functionality to combine two crc32{, c}s in GF(2)

2013-11-04T04:04:56+00:00

This patch adds a combinator to merge two or more crc32{,c}s
into a new one. This is useful for checksum computations of
fragmented skbs that use crc32/crc32c as checksums.

The arithmetics for combining both in the GF(2) was taken and
slightly modified from zlib. Only passing two crcs is insufficient
as two crcs and the length of the second piece is needed for
merging. The code is made generic, so that only polynomials
need to be passed for crc32_le resp. crc32c_le.

Signed-off-by: Daniel Borkmann 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller

lib: crc32: clean up spacing in test cases

2013-11-04T04:04:56+00:00

This is nothing more but a whitepace cleanup, as 80 chars is not a
hard but soft limit, and otherwise makes the test cases array really
look ugly. So fix it up.

Signed-off-by: Daniel Borkmann 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller

lib/crc32: update the comments of crc32_{be,le}_generic()

2013-09-11T22:58:38+00:00

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Gu Zheng 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds