prio_tree: cleanup prio_tree_left()/prio_tree_right()

Introduce iter_walk_down()/iter_walk_up() to remove the common code
between prio_tree_left() and prio_tree_right().

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
prio_tree: simplify prio_tree_expand()

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: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
prio_tree: introduce prio_set_parent()

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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/ and checkpatch: prefer __scanf to __attribute__((format(scanf,...)

It's equivalent to __printf, so prefer __scanf.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: add some --strict coding style checks

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: Joe Perches <joe@perches.com>
Cc: "Bruce W. Allen" <bruce.w.allan@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch.pl: be silent when -q and --ignore is given

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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: catch [ ... ] usage when not at the beginning of definition

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: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: allow simple character constants in #defines

Signed-off-by: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: handle string concatenation in simple #defines

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 <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: high precedence operators do not require additional parentheses in #defines

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 <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: add [] to type extensions

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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: add --strict tests for braces, comments and casts

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: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
checkpatch: whitespace - add/remove blank lines

Add blank lines between a few tests, remove an extraneous one.

Signed-off-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>
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>
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>
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>
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>
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>
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>