bitops: use try_cmpxchg in set_mask_bits and bit_clear_unless

Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
set_mask_bits and bit_clear_unless. x86 CMPXCHG instruction returns
success in ZF flag, so this change saves a compare after cmpxchg (and
related move instruction in front of cmpxchg).

Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails, enabling further code simplifications.

Link: https://lkml.kernel.org/r/20220822143851.3290-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib: add find_nth{,_and,_andnot}_bit()

Kernel lacks for a function that searches for Nth bit in a bitmap.
Usually people do it like this:
for_each_set_bit(bit, mask, size)
if (n-- == 0)
return bit;

We can do it more efficiently, if we:
1. find a word containing Nth bit, using hweight(); and
2. find the bit, using a helper fns(), that works similarly to
__ffs() and ffz().

fns() is implemented as a simple loop. For x86_64, there's PDEP instruction
to do that: ret = clz(pdep(1 << idx, num)). However, for large bitmaps the
most of improvement comes from using hweight(), so I kept fns() simple.

New find_nth_bit() is ~70 times faster on x86_64/kvm in find_bit benchmark:
find_nth_bit: 7154190 ns, 16411 iterations
for_each_bit: 505493126 ns, 16315 iterations

With all that, a family of 3 new functions is added, and used where
appropriate in the following patches.

Signed-off-by: Yury Norov <yury.norov@gmail.com>

wait_on_bit: add an acquire memory barrier

There are several places in the kernel where wait_on_bit is not followed
by a memory barrier (for example, in drivers/md/dm-bufio.c:new_read).

On architectures with weak memory ordering, it may happen that memory
accesses that follow wait_on_bit are reordered before wait_on_bit and
they may return invalid data.

Fix this class of bugs by introducing a new function "test_bit_acquire"
that works like test_bit, but has acquire memory ordering semantics.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: let optimize out non-atomic bitops on compile-time constants

Currently, many architecture-specific non-atomic bitop
implementations use inline asm or other hacks which are faster or
more robust when working with "real" variables (i.e. fields from
the structures etc.), but the compilers have no clue how to optimize
them out when called on compile-time constants. That said, the
following code:

DECLARE_BITMAP(foo, BITS_PER_LONG) = { }; // -> unsigned long foo[1];
unsigned long bar = BIT(BAR_BIT);
unsigned long baz = 0;

__set_bit(FOO_BIT, foo);
baz |= BIT(BAZ_BIT);

BUILD_BUG_ON(!__builtin_constant_p(test_bit(FOO_BIT, foo));
BUILD_BUG_ON(!__builtin_constant_p(bar & BAR_BIT));
BUILD_BUG_ON(!__builtin_constant_p(baz & BAZ_BIT));

triggers the first assertion on x86_64, which means that the
compiler is unable to evaluate it to a compile-time initializer
when the architecture-specific bitop is used even if it's obvious.
In order to let the compiler optimize out such cases, expand the
bitop() macro to use the "constant" C non-atomic bitop
implementations when all of the arguments passed are compile-time
constants, which means that the result will be a compile-time
constant as well, so that it produces more efficient and simple
code in 100% cases, comparing to the architecture-specific
counterparts.

The savings are architecture, compiler and compiler flags dependent,
for example, on x86_64 -O2:

GCC 12: add/remove: 78/29 grow/shrink: 332/525 up/down: 31325/-61560 (-30235)
LLVM 13: add/remove: 79/76 grow/shrink: 184/537 up/down: 55076/-141892 (-86816)
LLVM 14: add/remove: 10/3 grow/shrink: 93/138 up/down: 3705/-6992 (-3287)

and ARM64 (courtesy of Mark):

GCC 11: add/remove: 92/29 grow/shrink: 933/2766 up/down: 39340/-82580 (-43240)
LLVM 14: add/remove: 21/11 grow/shrink: 620/651 up/down: 12060/-15824 (-3764)

Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>

bitops: wrap non-atomic bitops with a transparent macro

In preparation for altering the non-atomic bitops with a macro, wrap
them in a transparent definition. This requires prepending one more
'_' to their names in order to be able to do that seamlessly. It is
a simple change, given that all the non-prefixed definitions are now
in asm-generic.
sparc32 already has several triple-underscored functions, so I had
to rename them ('___' -> 'sp32_').

Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>

bitops: define const_*() versions of the non-atomics

Define const_*() variants of the non-atomic bitops to be used when
the input arguments are compile-time constants, so that the compiler
will be always able to resolve those to compile-time constants as
well. Those are mostly direct aliases for generic_*() with one
exception for const_test_bit(): the original one is declared
atomic-safe and thus doesn't discard the `volatile` qualifier, so
in order to let optimize code, define it separately disregarding
the qualifier.
Add them to the compile-time type checks as well just in case.

Suggested-by: Marco Elver <elver@google.com>
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>

bitops: unify non-atomic bitops prototypes across architectures

Currently, there is a mess with the prototypes of the non-atomic
bitops across the different architectures:

ret bool, int, unsigned long
nr int, long, unsigned int, unsigned long
addr volatile unsigned long *, volatile void *

Thankfully, it doesn't provoke any bugs, but can sometimes make
the compiler angry when it's not handy at all.
Adjust all the prototypes to the following standard:

ret bool retval can be only 0 or 1
nr unsigned long native; signed makes no sense
addr volatile unsigned long * bitmaps are arrays of ulongs

Next, some architectures don't define 'arch_' versions as they don't
support instrumentation, others do. To make sure there is always the
same set of callables present and to ease any potential future
changes, make them all follow the rule:
* architecture-specific files define only 'arch_' versions;
* non-prefixed versions can be defined only in asm-generic files;
and place the non-prefixed definitions into a new file in
asm-generic to be included by non-instrumented architectures.

Finally, add some static assertions in order to prevent people from
making a mess in this room again.
I also used the %__always_inline attribute consistently, so that
they always get resolved to the actual operations.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>

include/linux: move for_each_bit() macros from bitops.h to find.h

for_each_bit() macros depend on find_bit() machinery, and so the
proper place for them is the find.h header.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

bitops: Add non-atomic bitops for pointers

cpumap needs to set, clear, and test the lowest bit in skb pointer in
various places. To make these checks less noisy, add pointer friendly
bitop macros that also do some typechecking to sanitize the argument.

These wrap the non-atomic bitops __set_bit, __clear_bit, and test_bit
but for pointer arguments. Pointer's address has to be passed in and it
is treated as an unsigned long *, since width and representation of
pointer and unsigned long match on targets Linux supports. They are
prefixed with double underscore to indicate lack of atomicity.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210702111825.491065-3-memxor@gmail.com

lib: add fast path for find_first_*_bit() and find_last_bit()

Similarly to bitmap functions, users would benefit if we'll handle a case
of small-size bitmaps that fit into a single word.

While here, move the find_last_bit() declaration to bitops/find.h where
other find_*_bit() functions sit.

Link: https://lkml.kernel.org/r/20210401003153.97325-11-yury.norov@gmail.com
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Alexey Klimov <aklimov@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Sterba <dsterba@suse.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jianpeng Ma <jianpeng.ma@intel.com>
Cc: Joe Perches <joe@perches.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Stefano Brivio <sbrivio@redhat.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/bitops.h: spelling s/synomyn/synonym/

Fix a misspelling of "synonym".

Link: https://lkml.kernel.org/r/20210108105305.2028120-1-geert+renesas@glider.be
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel.h: split out mathematical helpers

kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out
mathematical helpers.

At the same time convert users in header and lib folder to use new
header. Though for time being include new header back to kernel.h to
avoid twisted indirected includes for existing users.

[sfr@canb.auug.org.au: fix powerpc build]
Link: https://lkml.kernel.org/r/20201029150809.13059608@canb.auug.org.au

Link: https://lkml.kernel.org/r/20201028173212.41768-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: use the same mechanism for get_count_order[_long]

These two functions share the same logic.

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lkml.kernel.org/r/20200807085837.11697-3-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: simplify get_count_order_long()

These two cases could be unified into one.

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lkml.kernel.org/r/20200807085837.11697-2-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/bitops.h: avoid clang shift-count-overflow warnings

Clang normally does not warn about certain issues in inline functions when
it only happens in an eliminated code path. However if something else
goes wrong, it does tend to complain about the definition of hweight_long()
on 32-bit targets:

include/linux/bitops.h:75:41: error: shift count >= width of type [-Werror,-Wshift-count-overflow]
return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
^~~~~~~~~~~~
include/asm-generic/bitops/const_hweight.h:29:49: note: expanded from macro 'hweight64'
define hweight64(w) (__builtin_constant_p(w) ? __const_hweight64(w) : __arch_hweight64(w))
^~~~~~~~~~~~~~~~~~~~
include/asm-generic/bitops/const_hweight.h:21:76: note: expanded from macro '__const_hweight64'
define __const_hweight64(w) (__const_hweight32(w) + __const_hweight32((w) >> 32))
^ ~~
include/asm-generic/bitops/const_hweight.h:20:49: note: expanded from macro '__const_hweight32'
define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16))
^
include/asm-generic/bitops/const_hweight.h:19:72: note: expanded from macro '__const_hweight16'
define __const_hweight16(w) (__const_hweight8(w) + __const_hweight8((w) >> 8 ))
^
include/asm-generic/bitops/const_hweight.h:12:9: note: expanded from macro '__const_hweight8'
(!!((w) & (1ULL << 2))) + \

Adding an explicit cast to __u64 avoids that warning and makes it easier
to read other output.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Link: http://lkml.kernel.org/r/20200505135513.65265-1-arnd@arndb.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: always inline sign extension helpers

With CONFIG_CC_OPTIMIZE_FOR_SIZE, objtool reports:

drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: i915_gem_execbuffer2_ioctl()+0x5b7: call to gen8_canonical_addr() with UACCESS enabled

This means i915_gem_execbuffer2_ioctl() is calling gen8_canonical_addr()
from the user_access_begin/end critical region (i.e, with SMAP disabled).

While it's probably harmless in this case, in general we like to avoid
extra function calls in SMAP-disabled regions because it can open up
inadvertent security holes.

Fix the warning by changing the sign extension helpers to __always_inline.
This convinces GCC to inline gen8_canonical_addr().

The sign extension functions are trivial anyway, so it makes sense to
always inline them. With my test optimize-for-size-based config, this
actually shrinks the text size of i915_gem_execbuffer.o by 45 bytes -- and
no change for vmlinux.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://lkml.kernel.org/r/740179324b2b18b750b16295c48357f00b5fa9ed.1582982020.git.jpoimboe@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: more BITS_TO_* macros

Introduce BITS_TO_U64, BITS_TO_U32 and BITS_TO_BYTES as they are handy in
the following patches (BITS_TO_U32 specifically). Reimplement tools/
version of the macros according to the kernel implementation.

Also fix indentation for BITS_PER_TYPE definition.

Link: http://lkml.kernel.org/r/20200102043031.30357-3-yury.norov@gmail.com
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Amritha Nambiar <amritha.nambiar@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: "Tobin C . Harding" <tobin@kernel.org>
Cc: Vineet Gupta <vineet.gupta1@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ocfs2/dlm: move BITS_TO_BYTES() to bitops.h for wider use

There are users already and will be more of BITS_TO_BYTES() macro. Move
it to bitops.h for wider use.

In the case of ocfs2 the replacement is identical.

As for bnx2x, there are two places where floor version is used. In the
first case to calculate the amount of structures that can fit one memory
page. In this case obviously the ceiling variant is correct and
original code might have a potential bug, if amount of bits % 8 is not
0. In the second case the macro is used to calculate bytes transmitted
in one microsecond. This will work for all speeds which is multiply of
1Gbps without any change, for the rest new code will give ceiling value,
for instance 100Mbps will give 13 bytes, while old code gives 12 bytes
and the arithmetically correct one is 12.5 bytes. Further the value is
used to setup timer threshold which in any case has its own margins due
to certain resolution. I don't see here an issue with slightly shifting
thresholds for low speed connections, the card is supposed to utilize
highest available rate, which is usually 10Gbps.

Link: http://lkml.kernel.org/r/20200108121316.22411-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Acked-by: Sudarsana Reddy Kalluru <skalluru@marvell.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: introduce the for_each_set_clump8 macro

Pach series "Introduce the for_each_set_clump8 macro", v18.

While adding GPIO get_multiple/set_multiple callback support for various
drivers, I noticed a pattern of looping manifesting that would be useful
standardized as a macro.

This patchset introduces the for_each_set_clump8 macro and utilizes it
in several GPIO drivers. The for_each_set_clump macro8 facilitates a
for-loop syntax that iterates over a memory region entire groups of set
bits at a time.

For example, suppose you would like to iterate over a 32-bit integer 8
bits at a time, skipping over 8-bit groups with no set bit, where
XXXXXXXX represents the current 8-bit group:

Example: 10111110 00000000 11111111 00110011
First loop: 10111110 00000000 11111111 XXXXXXXX
Second loop: 10111110 00000000 XXXXXXXX 00110011
Third loop: XXXXXXXX 00000000 11111111 00110011

Each iteration of the loop returns the next 8-bit group that has at
least one set bit.

The for_each_set_clump8 macro has four parameters:

* start: set to the bit offset of the current clump
* clump: set to the current clump value
* bits: bitmap to search within
* size: bitmap size in number of bits

In this version of the patchset, the for_each_set_clump macro has been
reimplemented and simplified based on the suggestions provided by Rasmus
Villemoes and Andy Shevchenko in the version 4 submission.

In particular, the function of the for_each_set_clump macro has been
restricted to handle only 8-bit clumps; the drivers that use the
for_each_set_clump macro only handle 8-bit ports so a generic
for_each_set_clump implementation is not necessary. Thus, a solution
for large clumps (i.e. those larger than the width of a bitmap word)
can be postponed until a driver appears that actually requires such a
generic for_each_set_clump implementation.

For what it's worth, a semi-generic for_each_set_clump (i.e. for clumps
smaller than the width of a bitmap word) can be implemented by simply
replacing the hardcoded '8' and '0xFF' instances with respective
variables. I have not yet had a need for such an implementation, and
since it falls short of a true generic for_each_set_clump function, I
have decided to forgo such an implementation for now.

In addition, the bitmap_get_value8 and bitmap_set_value8 functions are
introduced to get and set 8-bit values respectively. Their use is based
on the behavior suggested in the patchset version 4 review.

This patch (of 14):

This macro iterates for each 8-bit group of bits (clump) with set bits,
within a bitmap memory region. For each iteration, "start" is set to
the bit offset of the found clump, while the respective clump value is
stored to the location pointed by "clump". Additionally, the
bitmap_get_value8 and bitmap_set_value8 functions are introduced to
respectively get and set an 8-bit value in a bitmap memory region.

[gustavo@embeddedor.com: fix potential sign-extension overflow]
Link: http://lkml.kernel.org/r/20191015184657.GA26541@embeddedor
[akpm@linux-foundation.org: s/ULL/UL/, per Joe]
[vilhelm.gray@gmail.com: add for_each_set_clump8 documentation]
Link: http://lkml.kernel.org/r/20191016161825.301082-1-vilhelm.gray@gmail.com
Link: http://lkml.kernel.org/r/893c3b4f03266c9496137cc98ac2b1bd27f92c73.1570641097.git.vilhelm.gray@gmail.com
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Suggested-by: Lukas Wunner <lukas@wunner.de>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Phil Reid <preid@electromag.com.au>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Cc: Morten Hein Tiljeset <morten.tiljeset@prevas.dk>
Cc: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib: introduce copy_struct_from_user() helper

A common pattern for syscall extensions is increasing the size of a
struct passed from userspace, such that the zero-value of the new fields
result in the old kernel behaviour (allowing for a mix of userspace and
kernel vintages to operate on one another in most cases).

While this interface exists for communication in both directions, only
one interface is straightforward to have reasonable semantics for
(userspace passing a struct to the kernel). For kernel returns to
userspace, what the correct semantics are (whether there should be an
error if userspace is unaware of a new extension) is very
syscall-dependent and thus probably cannot be unified between syscalls
(a good example of this problem is [1]).

Previously there was no common lib/ function that implemented
the necessary extension-checking semantics (and different syscalls
implemented them slightly differently or incompletely[2]). Future
patches replace common uses of this pattern to make use of
copy_struct_from_user().

Some in-kernel selftests that insure that the handling of alignment and
various byte patterns are all handled identically to memchr_inv() usage.

[1]: commit 1251201c0d34 ("sched/core: Fix uclamp ABI bug, clean up and
robustify sched_read_attr() ABI logic and code")

[2]: For instance {sched_setattr,perf_event_open,clone3}(2) all do do
similar checks to copy_struct_from_user() while rt_sigprocmask(2)
always rejects differently-sized struct arguments.

Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20191001011055.19283-2-cyphar@cyphar.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

include/linux/bitops.h: sanitize rotate primitives

The ror32 implementation (word >> shift) | (word << (32 - shift) has
undefined behaviour if shift is outside the [1, 31] range. Similarly
for the 64 bit variants. Most callers pass a compile-time constant
(naturally in that range), but there's an UBSAN report that these may
actually be called with a shift count of 0.

Instead of special-casing that, we can make them DTRT for all values of
shift while also avoiding UB. For some reason, this was already partly
done for rol32 (which was well-defined for [0, 31]). gcc 8 recognizes
these patterns as rotates, so for example

__u32 rol32(__u32 word, unsigned int shift)
{
return (word << (shift & 31)) | (word >> ((-shift) & 31));
}

compiles to

0000000000000020 <rol32>:
20: 89 f8 mov %edi,%eax
22: 89 f1 mov %esi,%ecx
24: d3 c0 rol %cl,%eax
26: c3 retq

Older compilers unfortunately do not do as well, but this only affects
the small minority of users that don't pass constants.

Due to integer promotions, ro[lr]8 were already well-defined for shifts
in [0, 8], and ro[lr]16 were mostly well-defined for shifts in [0, 16]
(only mostly - u16 gets promoted to _signed_ int, so if bit 15 is set,
word << 16 is undefined). For consistency, update those as well.

Link: http://lkml.kernel.org/r/20190410211906.2190-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reported-by: Ido Schimmel <idosch@mellanox.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Cc: Vadim Pasternak <vadimp@mellanox.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/bitops.h: set_mask_bits() to return old value

| > Also, set_mask_bits is used in fs quite a bit and we can possibly come up
| > with a generic llsc based implementation (w/o the cmpxchg loop)
|
| May I also suggest changing the return value of set_mask_bits() to old.
|
| You can compute the new value given old, but you cannot compute the old
| value given new, therefore old is the better return value. Also, no
| current user seems to use the return value, so changing it is without
| risk.

Link: http://lkml.kernel.org/g/20150807110955.GH16853@twins.programming.kicks-ass.net
Link: http://lkml.kernel.org/r/1548275584-18096-4-git-send-email-vgupta@synopsys.com
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: protect variables in bit_clear_unless() macro

Unprotected naming of local variables within bit_clear_unless() can easily
lead to using the wrong scope.

Noticed this by code review after having hit this issue in set_mask_bits()

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 85ad1d13ee9b ("md: set MD_CHANGE_PENDING in a atomic region")
Cc: Guoqing Jiang <gqjiang@suse.com>

bitops: protect variables in set_mask_bits() macro

Unprotected naming of local variables within the set_mask_bits() can easily
lead to using the wrong scope.

Noticed this when "set_mask_bits(&foo->bar, 0, mask)" behaved as no-op.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 00a1a053ebe5 ("ext4: atomically set inode->i_flags in ext4_set_inode_flags()")
Cc: Theodore Ts'o <tytso@mit.edu>

include/linux/bitops.h: introduce BITS_PER_TYPE

net_dim.h has a rather useful extension to BITS_PER_BYTE to compute the
number of bits in a type (BITS_PER_BYTE * sizeof(T)), so promote the macro
to bitops.h, alongside BITS_PER_BYTE, for wider usage.

Link: http://lkml.kernel.org/r/20180706094458.14116-1-chris@chris-wilson.co.uk
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andy Gospodarek <gospo@broadcom.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

locking/atomics, asm-generic: Move some macros from <linux/bitops.h> to a new <linux/bits.h> file

In preparation for implementing the asm-generic atomic bitops in terms
of atomic_long_*(), we need to prevent <asm/atomic.h> implementations from
pulling in <linux/bitops.h>. A common reason for this include is for the
BITS_PER_BYTE definition, so move this and some other BIT() and masking
macros into a new header file, <linux/bits.h>.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: yamada.masahiro@socionext.com
Link: https://lore.kernel.org/lkml/1529412794-17720-4-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

bitops: Revert cbe96375025e ("bitops: Add clear/set_bit32() to linux/bitops.h")

These ops are not endian safe and may break on architectures which have
aligment requirements.

Reverts: cbe96375025e ("bitops: Add clear/set_bit32() to linux/bitops.h")
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@linux.intel.com>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

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 & 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 >5
lines of source
- File already had some variant of a license header in it (even if <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 <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()

Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.

For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.

However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:

----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()

// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch

virtual patch

@ depends on patch @
expression E1, E2;
@@

- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)

@ depends on patch @
expression E;
@@

- ACCESS_ONCE(E)
+ READ_ONCE(E)
----

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

bitops: Introduce assign_bit()

A common idiom is to assign a value to a bit with:

if (value)
set_bit(nr, addr);
else
clear_bit(nr, addr);

Likewise common is the one-line expression variant:

value ? set_bit(nr, addr) : clear_bit(nr, addr);

Commit 9a8ac3ae682e ("dm mpath: cleanup QUEUE_IF_NO_PATH bit
manipulation by introducing assign_bit()") introduced assign_bit()
to the md subsystem for brevity.

Make it available to others, specifically gpiolib and the upcoming
driver for Maxim MAX3191x industrial serializer chips.

As requested by Peter Zijlstra, change the argument order to reflect
traditional "dst = src" in C, hence "assign_bit(nr, addr, value)".

Cc: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Neil Brown <neilb@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

bitops: Add clear/set_bit32() to linux/bitops.h

Add two simple wrappers around set_bit/clear_bit() that accept
the common case of an u32 array. This avoids writing
casts in all callers.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171013215645.23166-2-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

bitops: avoid integer overflow in GENMASK(_ULL)

GENMASK(_ULL) performs a left-shift of ~0UL(L), which technically
results in an integer overflow. clang raises a warning if the overflow
occurs in a preprocessor expression. Clear the low-order bits through a
substraction instead of the left-shift to avoid the overflow.

(akpm: no change in .text size in my testing)

Link: http://lkml.kernel.org/r/20170803212020.24939-1-mka@chromium.org
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c: fix align value calculation error

It causes double align requirement for __get_vm_area_node() if parameter
size is power of 2 and VM_IOREMAP is set in parameter flags, for example
size=0x10000 -> fls_long(0x10000)=17 -> align=0x20000

get_count_order_long() is implemented and can be used instead of
fls_long() for fixing the bug, for example size=0x10000 ->
get_count_order_long(0x10000)=16 -> align=0x10000

[akpm@linux-foundation.org: s/get_order_long()/get_count_order_long()/]
[zijun_hu@zoho.com: fixes]
Link: http://lkml.kernel.org/r/57AABC8B.1040409@zoho.com
[akpm@linux-foundation.org: locate get_count_order_long() next to get_count_order()]
[akpm@linux-foundation.org: move get_count_order[_long] definitions to pick up fls_long()]
[zijun_hu@htc.com: move out get_count_order[_long]() from __KERNEL__ scope]
Link: http://lkml.kernel.org/r/57B2C4CE.80303@zoho.com
Link: http://lkml.kernel.org/r/fc045ecf-20fa-0722-b3ac-9a6140488fad@zoho.com
Signed-off-by: zijun_hu <zijun_hu@htc.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: zijun_hu <zijun_hu@htc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

md: set MD_CHANGE_PENDING in a atomic region

Some code waits for a metadata update by:

1. flagging that it is needed (MD_CHANGE_DEVS or MD_CHANGE_CLEAN)
2. setting MD_CHANGE_PENDING and waking the management thread
3. waiting for MD_CHANGE_PENDING to be cleared

If the first two are done without locking, the code in md_update_sb()
which checks if it needs to repeat might test if an update is needed
before step 1, then clear MD_CHANGE_PENDING after step 2, resulting
in the wait returning early.

So make sure all places that set MD_CHANGE_PENDING are atomicial, and
bit_clear_unless (suggested by Neil) is introduced for the purpose.

Cc: Martin Kepplinger <martink@posteo.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: <linux-kernel@vger.kernel.org>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

bitops.h: correctly handle rol32 with 0 byte shift

ROL on a 32 bit integer with a shift of 32 or more is undefined and the
result is arch-dependent. Avoid this by handling the trivial case of
roling by 0 correctly.

The trivial solution of checking if shift is 0 breaks gcc's detection
of this code as a ROL instruction, which is unacceptable.

This bug was reported and fixed in GCC
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57157):

The standard rotate idiom,

(x << n) | (x >> (32 - n))

is recognized by gcc (for concreteness, I discuss only the case that x
is an uint32_t here).

However, this is portable C only for n in the range 0 < n < 32. For n
== 0, we get x >> 32 which gives undefined behaviour according to the
C standard (6.5.7, Bitwise shift operators). To portably support n ==
0, one has to write the rotate as something like

(x << n) | (x >> ((-n) & 31))

And this is apparently not recognized by gcc.

Note that this is broken on older GCCs and will result in slower ROL.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops.h: add sign_extend64()

Months back, this was discussed, see https://lkml.org/lkml/2015/1/18/289
The result was the 64-bit version being "likely fine", "valuable" and
"correct". The discussion fell asleep but since there are possible users,
let's add it.

Signed-off-by: Martin Kepplinger <martin.kepplinger@theobroma-systems.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: George Spelvin <linux@horizon.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Maxime Coquelin <maxime.coquelin@st.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops.h: improve sign_extend32()'s documentation

It is often overlooked that sign_extend32(), despite its name, is safe to
use for 16 and 8 bit types as well. This should help prevent sign
extension being done manually some other way.

Signed-off-by: Martin Kepplinger <martin.kepplinger@theobroma-systems.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: George Spelvin <linux@horizon.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Maxime Coquelin <maxime.coquelin@st.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

linux/bitmap: Force inlining of bitmap weight functions

With this config:

http://busybox.net/~vda/kernel_config_OPTIMIZE_INLINING_and_Os

gcc-4.7.2 generates many copies of these tiny functions:

bitmap_weight (55 copies):
55 push %rbp
48 89 e5 mov %rsp,%rbp
e8 3f 3a 8b 00 callq __bitmap_weight
5d pop %rbp
c3 retq

hweight_long (23 copies):
55 push %rbp
e8 b5 65 8e 00 callq __sw_hweight64
48 89 e5 mov %rsp,%rbp
5d pop %rbp
c3 retq

See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66122

This patch fixes this via s/inline/__always_inline/

While at it, replaced two "__inline__" with usual "inline"
(the rest of the source file uses the latter).

text data bss dec filename
86971357 17195880 36659200 140826437 vmlinux.before
86971120 17195912 36659200 140826232 vmlinux

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1438697716-28121-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

lib: find_*_bit reimplementation

This patchset does rework to find_bit function family to achieve better
performance, and decrease size of text. All rework is done in patch 1.
Patches 2 and 3 are about code moving and renaming.

It was boot-tested on x86_64 and MIPS (big-endian) machines.
Performance tests were ran on userspace with code like this:

/* addr[] is filled from /dev/urandom */
start = clock();
while (ret < nbits)
ret = find_next_bit(addr, nbits, ret + 1);

end = clock();
printf("%ld\t", (unsigned long) end - start);

On Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz measurements are: (for
find_next_bit, nbits is 8M, for find_first_bit - 80K)

find_next_bit: find_first_bit:
new current new current
26932 43151 14777 14925
26947 43182 14521 15423
26507 43824 15053 14705
27329 43759 14473 14777
26895 43367 14847 15023
26990 43693 15103 15163
26775 43299 15067 15232
27282 42752 14544 15121
27504 43088 14644 14858
26761 43856 14699 15193
26692 43075 14781 14681
27137 42969 14451 15061
... ...

find_next_bit performance gain is 35-40%;
find_first_bit - no measurable difference.

On ARM machine, there is arch-specific implementation for find_bit.

Thanks a lot to George Spelvin and Rasmus Villemoes for hints and
helpful discussions.

This patch (of 3):

New implementations takes less space in source file (see diffstat) and in
object. For me it's 710 vs 453 bytes of text. It also shows better
performance.

find_last_bit description fixed due to obvious typo.

[akpm@linux-foundation.org: include linux/bitmap.h, per Rasmus]
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: George Spelvin <linux@horizon.com>
Cc: Alexey Klimov <klimov.linux@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Valentin Rothberg <valentinrothberg@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: Fix shift overflow in GENMASK macros

On some 32 bits architectures, including x86, GENMASK(31, 0) returns 0
instead of the expected ~0UL.

This is the same on some 64 bits architectures with GENMASK_ULL(63, 0).

This is due to an overflow in the shift operand, 1 << 32 for GENMASK,
1 << 64 for GENMASK_ULL.

Reported-by: Eric Paire <eric.paire@st.com>
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.13+
Cc: linux@rasmusvillemoes.dk
Cc: gong.chen@linux.intel.com
Cc: John Sullivan <jsrhbz@kanargh.force9.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Fixes: 10ef6b0dffe4 ("bitops: Introduce a more generic BITMASK macro")
Link: http://lkml.kernel.org/r/1415267659-10563-1-git-send-email-maxime.coquelin@st.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

locking: Remove deprecated smp_mb__() barriers

Its been a while and there are no in-tree users left, so remove the
deprecated barriers.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chen, Gong <gong.chen@linux.intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Joe Perches <joe@perches.com>
Cc: John Sullivan <jsrhbz@kanargh.force9.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch: Prepare for smp_mb__{before,after}_atomic()

Since the smp_mb__{before,after}*() ops are fundamentally dependent on
how an arch can implement atomics it doesn't make sense to have 3
variants of them. They must all be the same.

Furthermore, the 3 variants suggest they're only valid for those 3
atomic ops, while we have many more where they could be applied.

So move away from
smp_mb__{before,after}_{atomic,clear}_{dec,inc,bit}() and reduce the
interface to just the two: smp_mb__{before,after}_atomic().

This patch prepares the way by introducing default implementations in
asm-generic/barrier.h that default to a full barrier and providing
__deprecated inlines for the previous 6 barriers if they're not
provided by the arch.

This should allow for a mostly painless transition (lots of deprecated
warns in the interim).

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-wr59327qdyi9mbzn6x937s4e@git.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Chen, Gong" <gong.chen@linux.intel.com>
Cc: John Sullivan <jsrhbz@kanargh.force9.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

ext4: atomically set inode->i_flags in ext4_set_inode_flags()

Use cmpxchg() to atomically set i_flags instead of clearing out the
S_IMMUTABLE, S_APPEND, etc. flags and then setting them from the
EXT4_IMMUTABLE_FL, EXT4_APPEND_FL flags, since this opens up a race
where an immutable file has the immutable flag cleared for a brief
window of time.

Reported-by: John Sullivan <jsrhbz@kanargh.force9.co.uk>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: Introduce a more generic BITMASK macro

GENMASK is used to create a contiguous bitmask([hi:lo]). It is
implemented twice in current kernel. One is in EDAC driver, the other
is in SiS/XGI FB driver. Move it to a more generic place for other
usage.

Signed-off-by: Chen, Gong <gong.chen@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

bitops: Introduce BIT_ULL

Adding BIT(x) equivalent for unsigned long long type, BIT_ULL(x). Also
added BIT_ULL_MASK and BIT_ULL_WORD.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

bitops: introduce for_each_clear_bit()

Introduce for_each_clear_bit() and for_each_clear_bit_from(). They are
similar to for_each_set_bit() and list_for_each_set_bit_from(), but they
iterate over all the cleared bits in a memory region.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Stefano Panella <stefano.panella@csr.com>
Cc: David Vrabel <david.vrabel@csr.com>
Cc: Sergei Shtylyov <sshtylyov@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: remove for_each_set_bit_cont()

Remove for_each_set_bit_cont() after confirming that no one uses
for_each_set_bit_cont() anymore.

[sfr@canb.auug.org.au: regmap: cope with bitops API change]
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: rename for_each_set_bit_cont() in favor of analogous list.h function

This renames for_each_set_bit_cont() to for_each_set_bit_from() because
it is analogous to list_for_each_entry_from() in list.h rather than
list_for_each_entry_continue().

This doesn't remove for_each_set_bit_cont() for now.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

crypto: sha512 - use standard ror64()

Use standard ror64() instead of hand-written.
There is no standard ror64, so create it.

The difference is shift value being "unsigned int" instead of uint64_t
(for which there is no reason). gcc starts to emit native ROR instructions
which it doesn't do for some reason currently. This should make the code
faster.

Patch survives in-tree crypto test and ping flood with hmac(sha512) on.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: sha512 - use standard ror64()

Use standard ror64() instead of hand-written.
There is no standard ror64, so create it.

The difference is shift value being "unsigned int" instead of uint64_t
(for which there is no reason). gcc starts to emit native ROR instructions
which it doesn't do for some reason currently. This should make the code
faster.

Patch survives in-tree crypto test and ping flood with hmac(sha512) on.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

perf, x86: Implement event scheduler helper functions

This patch introduces x86 perf scheduler code helper functions. We
need this to later add more complex functionality to support
overlapping counter constraints (next patch).

The algorithm is modified so that the range of weight values is now
generated from the constraints. There shouldn't be other functional
changes.

With the helper functions the scheduler is controlled. There are
functions to initialize, traverse the event list, find unused counters
etc. The scheduler keeps its own state.

V3:
* Added macro for_each_set_bit_cont().
* Changed functions interfaces of perf_sched_find_counter() and
perf_sched_next_event() to use bool as return value.
* Added some comments to make code better understandable.

V4:
* Fix broken event assignment if weight of the first event is not
wmin (perf_sched_init()).

Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1321616122-1533-2-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch: remove CONFIG_GENERIC_FIND_{NEXT_BIT,BIT_LE,LAST_BIT}

By the previous style change, CONFIG_GENERIC_FIND_NEXT_BIT,
CONFIG_GENERIC_FIND_BIT_LE, and CONFIG_GENERIC_FIND_LAST_BIT are not used
to test for existence of find bitops anymore.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: add #ifndef for each of find bitops

The style that we normally use in asm-generic is to test the macro itself
for existence, so in asm-generic, do:

#ifndef find_next_zero_bit_le
extern unsigned long find_next_zero_bit_le(const void *addr,
unsigned long size, unsigned long offset);
#endif

and in the architectures, write

static inline unsigned long find_next_zero_bit_le(const void *addr,
unsigned long size, unsigned long offset)
#define find_next_zero_bit_le find_next_zero_bit_le

This adds the #ifndef for each of the find bitops in the generic header
and source files.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: Provide generic sign_extend32 function

This patch moves code out from wireless drivers where two different
functions are defined in three code locations for the same purpose and
provides a common function to sign extend a 32-bit value.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

bitops: remove duplicated extern declarations

If CONFIG_GENERIC_FIND_NEXT_BIT is enabled, find_next_bit() and
find_next_zero_bit() are doubly declared in asm-generic/bitops/find.h
and linux/bitops.h.

asm/bitops.h includes asm-generic/bitops/find.h if and only if the
architecture enables CONFIG_GENERIC_FIND_NEXT_BIT. And asm/bitops.h
is included by linux/bitops.h

So we can just remove the extern declarations of find_next_bit() and
find_next_zero_bit() in linux/bitops.h.

Also we can remove unneeded #ifndef CONFIG_GENERIC_FIND_NEXT_BIT in
asm-generic/bitops/find.h.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

bitops: make asm-generic/bitops/find.h more generic

asm-generic/bitops/find.h has the extern declarations of find_next_bit()
and find_next_zero_bit() and the macro definitions of find_first_bit()
and find_first_zero_bit(). It is only usable by the architectures which
enables CONFIG_GENERIC_FIND_NEXT_BIT and disables
CONFIG_GENERIC_FIND_FIRST_BIT.

x86 and tile enable both CONFIG_GENERIC_FIND_NEXT_BIT and
CONFIG_GENERIC_FIND_FIRST_BIT. These architectures cannot include
asm-generic/bitops/find.h in their asm/bitops.h. So ifdefed extern
declarations of find_first_bit and find_first_zero_bit() are put in
linux/bitops.h.

This makes asm-generic/bitops/find.h usable by these architectures
and use it. Also this change is needed for the forthcoming duplicated
extern declarations cleanup.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Chris Metcalf <cmetcalf@tilera.com>

arch, hweight: Fix compilation errors

Fix function prototype visibility issues when compiling for non-x86
architectures. Tested with crosstool
(ftp://ftp.kernel.org/pub/tools/crosstool/) with alpha, ia64 and sparc
targets.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <20100503130736.GD26107@aftab>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

bitops: remove temporary for_each_bit()

Migration has been completed so remove this now. There's one straggler in
linux-next's drivers/mtd/sm_ftl.c. A patch has been sent.

Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: Optimize hweight() by making use of compile-time evaluation

Rename the extisting runtime hweight() implementations to
__arch_hweight(), rename the compile-time versions to __const_hweight()
and then have hweight() pick between them.

Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100318111929.GB11152@aftab>
Acked-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <1265028224.24455.154.camel@laptop>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

bitops: rename for_each_bit() to for_each_set_bit()

Rename for_each_bit to for_each_set_bit in the kernel source tree. To
permit for_each_clear_bit(), should that ever be added.

The patch includes a macro to map the old for_each_bit() onto the new
for_each_set_bit(). This is a (very) temporary thing to ease the migration.

[akpm@linux-foundation.org: add temporary for_each_bit()]
Suggested-by: Alexey Dobriyan <adobriyan@gmail.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bitops: Ensure the compile time HWEIGHT is only used for such

Avoid accidental misuse by failing to compile things

Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

bitops: Provide compile time HWEIGHT{8,16,32,64}

Provide compile time versions of hweight.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <20100122155535.797688466@chello.nl>
[ Remove some whitespace damage while we are at it ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

bitops: Add __ffs64 bitop

Finds the first set bit in a 64 bit word. This is required in order
to fix a bug in GFS2, but I think it should be a generic function
in case of future users.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Willy Tarreau <w@1wt.eu>

bitmap: find_last_bit()

Impact: New API

As the name suggests. For the moment everyone uses the generic one.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

bitops: remove "optimizations"

The mapsize optimizations which were moved from x86 to the generic
code in commit 64970b68d2b3ed32b964b0b30b1b98518fde388e increased the
binary size on non x86 architectures.

Looking into the real effects of the "optimizations" it turned out
that they are not used in find_next_bit() and find_next_zero_bit().

The ones in find_first_bit() and find_first_zero_bit() are used in a
couple of places but none of them is a real hot path.

Remove the "optimizations" all together and call the library functions
unconditionally.

Boot-tested on x86 and compile tested on every cross compiler I have.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Avoid divides in BITS_TO_LONGS

BITS_PER_LONG is a signed value (32 or 64)

DIV_ROUND_UP(nr, BITS_PER_LONG) performs signed arithmetic if "nr" is signed too.

Converting BITS_TO_LONGS(nr) to DIV_ROUND_UP(nr, BITS_PER_BYTE *
sizeof(long)) makes sure compiler can perform a right shift, even if "nr"
is a signed value, instead of an expensive integer divide.

Applying this patch saves 141 bytes on x86 when CONFIG_CC_OPTIMIZE_FOR_SIZE=y
and speedup bitmap operations.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86: optimize find_first_bit for small bitmaps

Avoid a call to find_first_bit if the bitmap size is know at
compile time and small enough to fit in a single long integer.
Modeled after an optimization in the original x86_64-specific
code.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: generic versions of find_first_(zero_)bit, convert i386

Generic versions of __find_first_bit and __find_first_zero_bit
are introduced as simplified versions of __find_next_bit and
__find_next_zero_bit. Their compilation and use are guarded by
a new config variable GENERIC_FIND_FIRST_BIT.

The generic versions of find_first_bit and find_first_zero_bit
are implemented in terms of the newly introduced __find_first_bit
and __find_first_zero_bit.

This patch does not remove the i386-specific implementation,
but it does switch i386 to use the generic functions by setting
GENERIC_FIND_FIRST_BIT=y for X86_32.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, generic: optimize find_next_(zero_)bit for small constant-size bitmaps

This moves an optimization for searching constant-sized small
bitmaps form x86_64-specific to generic code.

On an i386 defconfig (the x86#testing one), the size of vmlinux hardly
changes with this applied. I have observed only four places where this
optimization avoids a call into find_next_bit:

In the functions return_unused_surplus_pages, alloc_fresh_huge_page,
and adjust_pool_surplus, this patch avoids a call for a 1-bit bitmap.
In __next_cpu a call is avoided for a 32-bit bitmap. That's it.

On x86_64, 52 locations are optimized with a minimal increase in
code size:

Current #testing defconfig:
146 x bsf, 27 x find_next_*bit
text data bss dec hex filename
5392637 846592 724424 6963653 6a41c5 vmlinux

After removing the x86_64 specific optimization for find_next_*bit:
94 x bsf, 79 x find_next_*bit
text data bss dec hex filename
5392358 846592 724424 6963374 6a40ae vmlinux

After this patch (making the optimization generic):
146 x bsf, 27 x find_next_*bit
text data bss dec hex filename
5392396 846592 724424 6963412 6a40d4 vmlinux

[ tglx@linutronix.de: build fixes ]

Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel: add bit rotation helpers for 16 and 8 bit

Will replace open-coded variants elsewhere. Done in the same
style as the 32-bit versions.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John W. Linville <linville@tuxdriver.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jiri Benc <jbenc@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

remove BITS_TO_TYPE macro

remove BITS_TO_TYPE macro

I realized, that it is actually the same as DIV_ROUND_UP, use it instead.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

define global BIT macro

define global BIT macro

move all local BIT defines to the new globally define macro.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

define first set of BIT* macros

define first set of BIT* macros

- move BITOP_MASK and BITOP_WORD from asm-generic/bitops/atomic.h to
include/linux/bitops.h and rename it to BIT_MASK and BIT_WORD
- move BITS_TO_LONGS and BITS_PER_BYTE to bitops.h too and allow easily
define another BITS_TO_something (e.g. in event.c) by BITS_TO_TYPE macro
Remaining (and common) BIT macro will be defined after all occurences and
conflicts will be sorted out in the patches.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

I/OAT: Add support for MSI and MSI-X

Add support for MSI and MSI-X interrupt handling, including the ability
to choose the desired interrupt method.

Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>
[bunk@kernel.org: drivers/dma/ioat_dma.c: make 3 functions static]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] fix various kernel-doc in header files

Fix a number of kernel-doc entries for header files in include/linux by
making sure they begin with the appropriate '/**' notation and use @var
notation.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] bitops: remove unused generic bitops in include/linux/bitops.h

generic_{ffs,fls,fls64,hweight{64,32,16,8}}() were moved into
include/asm-generic/bitops.h. So all architectures don't use them.

Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] roundup_pow_of_two() 64-bit fix

fls() takes an integer, so roundup_pow_of_two() is busted for ulongs larger
than 2^32-1.

Fix this by implementing and using fls_long().

(Why does roundup_pow_of_two() return a long?)

(Why is roundup_pow_of_two() __attribute_const__ whereas long_log2() is
__attribute_pure__?)

(Why does long_log2() suck so much? Because we were missing fls_long()?)

Cc: Roland Dreier <rdreier@cisco.com>
Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Cc: John Hawkes <hawkes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] fix generic_fls64()

Noticed by Rune Torgersen.

Fix generic_fls64(). tcp_cubic is using fls64().

Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[FLS64]: generic version

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[PATCH] x86-64/i386: Intel HT, Multi core detection fixes

Fields obtained through cpuid vector 0x1(ebx[16:23]) and
vector 0x4(eax[14:25], eax[26:31]) indicate the maximum values and might not
always be the same as what is available and what OS sees. So make sure
"siblings" and "cpu cores" values in /proc/cpuinfo reflect the values as seen
by OS instead of what cpuid instruction says. This will also fix the buggy BIOS
cases (for example where cpuid on a single core cpu says there are "2" siblings,
even when HT is disabled in the BIOS.
http://bugzilla.kernel.org/show_bug.cgi?id=4359)

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!