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<title>user/sven/linux.git/include/linux/bitops.h, branch v5.15.26</title>
<subtitle>Linux Kernel
</subtitle>
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<updated>2021-07-08T03:01:45Z</updated>
<entry>
<title>bitops: Add non-atomic bitops for pointers</title>
<updated>2021-07-08T03:01:45Z</updated>
<author>
<name>Kumar Kartikeya Dwivedi</name>
<email>memxor@gmail.com</email>
</author>
<published>2021-07-02T11:18:22Z</published>
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<id>urn:sha1:cb0f80039fb7ec9981a74d22019daaa85ff51a3d</id>
<content type='text'>
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 &lt;memxor@gmail.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Reviewed-by: Toke Høiland-Jørgensen &lt;toke@redhat.com&gt;
Link: https://lore.kernel.org/bpf/20210702111825.491065-3-memxor@gmail.com
</content>
</entry>
<entry>
<title>lib: add fast path for find_first_*_bit() and find_last_bit()</title>
<updated>2021-05-07T02:24:12Z</updated>
<author>
<name>Yury Norov</name>
<email>yury.norov@gmail.com</email>
</author>
<published>2021-05-07T01:03:14Z</published>
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<id>urn:sha1:2cc7b6a44ac21d31b398b03f4845c53152070416</id>
<content type='text'>
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 &lt;yury.norov@gmail.com&gt;
Acked-by: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Acked-by: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Cc: Alexey Klimov &lt;aklimov@redhat.com&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: David Sterba &lt;dsterba@suse.com&gt;
Cc: Dennis Zhou &lt;dennis@kernel.org&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Jianpeng Ma &lt;jianpeng.ma@intel.com&gt;
Cc: Joe Perches &lt;joe@perches.com&gt;
Cc: John Paul Adrian Glaubitz &lt;glaubitz@physik.fu-berlin.de&gt;
Cc: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: Stefano Brivio &lt;sbrivio@redhat.com&gt;
Cc: Wei Yang &lt;richard.weiyang@linux.alibaba.com&gt;
Cc: Wolfram Sang &lt;wsa+renesas@sang-engineering.com&gt;
Cc: Yoshinori Sato &lt;ysato@users.osdn.me&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>include/linux/bitops.h: spelling s/synomyn/synonym/</title>
<updated>2021-02-26T17:41:04Z</updated>
<author>
<name>Geert Uytterhoeven</name>
<email>geert+renesas@glider.be</email>
</author>
<published>2021-02-26T01:21:37Z</published>
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<id>urn:sha1:4945cca232ce8bc699b8743f2436af664c471b96</id>
<content type='text'>
Fix a misspelling of "synonym".

Link: https://lkml.kernel.org/r/20210108105305.2028120-1-geert+renesas@glider.be
Signed-off-by: Geert Uytterhoeven &lt;geert+renesas@glider.be&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>kernel.h: split out mathematical helpers</title>
<updated>2020-12-16T06:46:15Z</updated>
<author>
<name>Andy Shevchenko</name>
<email>andriy.shevchenko@linux.intel.com</email>
</author>
<published>2020-12-16T04:42:48Z</published>
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<id>urn:sha1:aa6159ab99a9ab5df835b4750b66cf132a5aa292</id>
<content type='text'>
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 &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: "Paul E. McKenney" &lt;paulmck@kernel.org&gt;
Cc: Trond Myklebust &lt;trond.myklebust@hammerspace.com&gt;
Cc: Jeff Layton &lt;jlayton@kernel.org&gt;
Cc: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>bitops: use the same mechanism for get_count_order[_long]</title>
<updated>2020-10-16T18:11:20Z</updated>
<author>
<name>Wei Yang</name>
<email>richard.weiyang@linux.alibaba.com</email>
</author>
<published>2020-10-16T03:11:46Z</published>
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<id>urn:sha1:004fba1ae6ddd66ba0faa4f60c603b3ca77b3554</id>
<content type='text'>
These two functions share the same logic.

Signed-off-by: Wei Yang &lt;richard.weiyang@linux.alibaba.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Christian Brauner &lt;christian.brauner@ubuntu.com&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Link: https://lkml.kernel.org/r/20200807085837.11697-3-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>bitops: simplify get_count_order_long()</title>
<updated>2020-10-16T18:11:20Z</updated>
<author>
<name>Wei Yang</name>
<email>richard.weiyang@linux.alibaba.com</email>
</author>
<published>2020-10-16T03:11:41Z</published>
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<id>urn:sha1:a9eb63705e379f10a3c9d13fc6aee8b50805e862</id>
<content type='text'>
These two cases could be unified into one.

Signed-off-by: Wei Yang &lt;richard.weiyang@linux.alibaba.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Christian Brauner &lt;christian.brauner@ubuntu.com&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Link: https://lkml.kernel.org/r/20200807085837.11697-2-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>include/linux/bitops.h: avoid clang shift-count-overflow warnings</title>
<updated>2020-06-05T02:06:25Z</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@arndb.de</email>
</author>
<published>2020-06-04T23:50:30Z</published>
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<id>urn:sha1:bd93f003b7462ae39a43c531abca37fe7073b866</id>
<content type='text'>
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 &gt;= 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) &gt;&gt; 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) &gt;&gt; 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)  &gt;&gt; 8 ))
                                                                         ^
  include/asm-generic/bitops/const_hweight.h:12:9: note: expanded from macro '__const_hweight8'
            (!!((w) &amp; (1ULL &lt;&lt; 2))) +     \

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

Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Acked-by: Christian Brauner &lt;christian.brauner@ubuntu.com&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Cc: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Cc: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Link: http://lkml.kernel.org/r/20200505135513.65265-1-arnd@arndb.de
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>bitops: always inline sign extension helpers</title>
<updated>2020-04-07T17:43:42Z</updated>
<author>
<name>Josh Poimboeuf</name>
<email>jpoimboe@redhat.com</email>
</author>
<published>2020-04-07T03:09:43Z</published>
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<id>urn:sha1:f80ac98a641a03097cbc9fdfd4b6a41a8dd3b7ae</id>
<content type='text'>
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 &lt;rdunlap@infradead.org&gt;
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Link: http://lkml.kernel.org/r/740179324b2b18b750b16295c48357f00b5fa9ed.1582982020.git.jpoimboe@redhat.com
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>bitops: more BITS_TO_* macros</title>
<updated>2020-02-04T03:05:26Z</updated>
<author>
<name>Yury Norov</name>
<email>yury.norov@gmail.com</email>
</author>
<published>2020-02-04T01:37:24Z</published>
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<id>urn:sha1:0bddc1bd05d6973fee9303005abab6567f743ea7</id>
<content type='text'>
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 &lt;yury.norov@gmail.com&gt;
Reviewed-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Amritha Nambiar &lt;amritha.nambiar@intel.com&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Matthew Wilcox &lt;willy@infradead.org&gt;
Cc: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
Cc: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Cc: Steffen Klassert &lt;steffen.klassert@secunet.com&gt;
Cc: "Tobin C . Harding" &lt;tobin@kernel.org&gt;
Cc: Vineet Gupta &lt;vineet.gupta1@synopsys.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Willem de Bruijn &lt;willemb@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>ocfs2/dlm: move BITS_TO_BYTES() to bitops.h for wider use</title>
<updated>2020-01-31T18:30:36Z</updated>
<author>
<name>Andy Shevchenko</name>
<email>andriy.shevchenko@linux.intel.com</email>
</author>
<published>2020-01-31T06:11:47Z</published>
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<id>urn:sha1:dd3e7cba16274831f5a69f071ed3cf13ffb352ea</id>
<content type='text'>
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 &lt;andriy.shevchenko@linux.intel.com&gt;
Reviewed-by: Joseph Qi &lt;joseph.qi@linux.alibaba.com&gt;
Acked-by: Sudarsana Reddy Kalluru &lt;skalluru@marvell.com&gt;
Cc: Mark Fasheh &lt;mark@fasheh.com&gt;
Cc: Joel Becker &lt;jlbec@evilplan.org&gt;
Cc: Junxiao Bi &lt;junxiao.bi@oracle.com&gt;
Cc: Changwei Ge &lt;gechangwei@live.cn&gt;
Cc: Gang He &lt;ghe@suse.com&gt;
Cc: Jun Piao &lt;piaojun@huawei.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
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