<feed xmlns='http://www.w3.org/2005/Atom'>
<title>user/sven/linux.git/include/linux/minmax.h, branch v6.10.7</title>
<subtitle>Linux Kernel
</subtitle>
<id>https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v6.10.7</id>
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<updated>2023-10-18T21:43:22Z</updated>
<entry>
<title>minmax: relax check to allow comparison between unsigned arguments and signed constants</title>
<updated>2023-10-18T21:43:22Z</updated>
<author>
<name>David Laight</name>
<email>David.Laight@ACULAB.COM</email>
</author>
<published>2023-09-18T08:19:25Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=867046cc7027703f60a46339ffde91a1970f2901'/>
<id>urn:sha1:867046cc7027703f60a46339ffde91a1970f2901</id>
<content type='text'>
Allow (for example) min(unsigned_var, 20).

The opposite min(signed_var, 20u) is still errored.

Since a comparison between signed and unsigned never makes the unsigned
value negative it is only necessary to adjust the __types_ok() test.

Link: https://lkml.kernel.org/r/633b64e2f39e46bb8234809c5595b8c7@AcuMS.aculab.com
Signed-off-by: David Laight &lt;david.laight@aculab.com&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Christoph Hellwig &lt;hch@infradead.org&gt;
Cc: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>minmax: allow comparisons of 'int' against 'unsigned char/short'</title>
<updated>2023-10-18T21:43:22Z</updated>
<author>
<name>David Laight</name>
<email>David.Laight@ACULAB.COM</email>
</author>
<published>2023-09-18T08:18:40Z</published>
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<id>urn:sha1:4ead534fba42fc4fd41163297528d2aa731cd121</id>
<content type='text'>
Since 'unsigned char/short' get promoted to 'signed int' it is safe to
compare them against an 'int' value.

Link: https://lkml.kernel.org/r/8732ef5f809c47c28a7be47c938b28d4@AcuMS.aculab.com
Signed-off-by: David Laight &lt;david.laight@aculab.com&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Christoph Hellwig &lt;hch@infradead.org&gt;
Cc: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>minmax: fix indentation of __cmp_once() and __clamp_once()</title>
<updated>2023-10-18T21:43:22Z</updated>
<author>
<name>David Laight</name>
<email>David.Laight@ACULAB.COM</email>
</author>
<published>2023-09-18T08:17:57Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=f4b84b2ff851f01d0fac619eadef47eb41648534'/>
<id>urn:sha1:f4b84b2ff851f01d0fac619eadef47eb41648534</id>
<content type='text'>
Remove the extra indentation and align continuation markers.

Link: https://lkml.kernel.org/r/bed41317a05c498ea0209eafbcab45a5@AcuMS.aculab.com
Signed-off-by: David Laight &lt;david.laight@aculab.com&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Christoph Hellwig &lt;hch@infradead.org&gt;
Cc: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>minmax: allow min()/max()/clamp() if the arguments have the same signedness.</title>
<updated>2023-10-18T21:43:22Z</updated>
<author>
<name>David Laight</name>
<email>David.Laight@ACULAB.COM</email>
</author>
<published>2023-09-18T08:17:15Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=d03eba99f5bf7cbc6e2fdde3b6fa36954ad58e09'/>
<id>urn:sha1:d03eba99f5bf7cbc6e2fdde3b6fa36954ad58e09</id>
<content type='text'>
The type-check in min()/max() is there to stop unexpected results if a
negative value gets converted to a large unsigned value.  However it also
rejects 'unsigned int' v 'unsigned long' compares which are common and
never problematc.

Replace the 'same type' check with a 'same signedness' check.

The new test isn't itself a compile time error, so use static_assert() to
report the error and give a meaningful error message.

Due to the way builtin_choose_expr() works detecting the error in the
'non-constant' side (where static_assert() can be used) also detects
errors when the arguments are constant.

Link: https://lkml.kernel.org/r/fe7e6c542e094bfca655abcd323c1c98@AcuMS.aculab.com
Signed-off-by: David Laight &lt;david.laight@aculab.com&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Christoph Hellwig &lt;hch@infradead.org&gt;
Cc: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>minmax: add umin(a, b) and umax(a, b)</title>
<updated>2023-10-18T21:43:22Z</updated>
<author>
<name>David Laight</name>
<email>David.Laight@ACULAB.COM</email>
</author>
<published>2023-09-18T08:16:30Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=80fcac55385ccb710d33a20dc1caaef29bd5a921'/>
<id>urn:sha1:80fcac55385ccb710d33a20dc1caaef29bd5a921</id>
<content type='text'>
Patch series "minmax: Relax type checks in min() and max()", v4.

The min() (etc) functions in minmax.h require that the arguments have
exactly the same types.

However when the type check fails, rather than look at the types and fix
the type of a variable/constant, everyone seems to jump on min_t().  In
reality min_t() ought to be rare - when something unusual is being done,
not normality.

The orginal min() (added in 2.4.9) replaced several inline functions and
included the type - so matched the implicit casting of the function call. 
This was renamed min_t() in 2.4.10 and the current min() added.  There is
no actual indication that the conversion of negatve values to large
unsigned values has ever been an actual problem.

A quick grep shows 5734 min() and 4597 min_t().  Having the casts on
almost half of the calls shows that something is clearly wrong.

If the wrong type is picked (and it is far too easy to pick the type of
the result instead of the larger input) then significant bits can get
discarded.

Pretty much the worst example is in the derived clamp_val(), consider:
        unsigned char x = 200u;
        y = clamp_val(x, 10u, 300u);

I also suspect that many of the min_t(u16, ...) are actually wrong.  For
example copy_data() in printk_ringbuffer.c contains:

        data_size = min_t(u16, buf_size, len);

Here buf_size is 'unsigned int' and len 'u16', pass a 64k buffer (can you
prove that doesn't happen?) and no data is returned.  Apparantly it did -
and has since been fixed.

The only reason that most of the min_t() are 'fine' is that pretty much
all the values in the kernel are between 0 and INT_MAX.

Patch 1 adds umin(), this uses integer promotions to convert both
arguments to 'unsigned long long'.  It can be used to compare a signed
type that is known to contain a non-negative value with an unsigned type. 
The compiler typically optimises it all away.  Added first so that it can
be referred to in patch 2.

Patch 2 replaces the 'same type' check with a 'same signedness' one.  This
makes min(unsigned_int_var, sizeof()) be ok.  The error message is also
improved and will contain the expanded form of both arguments (useful for
seeing how constants are defined).

Patch 3 just fixes some whitespace.

Patch 4 allows comparisons of 'unsigned char' and 'unsigned short' to
signed types.  The integer promotion rules convert them both to 'signed
int' prior to the comparison so they can never cause a negative value be
converted to a large positive one.

Patch 5 (rewritted for v4) allows comparisons of unsigned values against
non-negative constant integer expressions.  This makes
min(unsigned_int_var, 4) be ok.

The only common case that is still errored is the comparison of signed
values against unsigned constant integer expressions below __INT_MAX__. 
Typcally min(int_val, sizeof (foo)), the real fix for this is casting the
constant: min(int_var, (int)sizeof (foo)).

With all the patches applied pretty much all the min_t() could be replaced
by min(), and most of the rest by umin().  However they all need careful
inspection due to code like:

        sz = min_t(unsigned char, sz - 1, LIM - 1) + 1;

which converts 0 to LIM.


This patch (of 6):

umin() and umax() can be used when min()/max() errors a signed v unsigned
compare when the signed value is known to be non-negative.

Unlike min_t(some_unsigned_type, a, b) umin() will never mask off high
bits if an inappropriate type is selected.

The '+ 0u + 0ul + 0ull' may look strange.
The '+ 0u' is needed for 'signed int' on 64bit systems.
The '+ 0ul' is needed for 'signed long' on 32bit systems.
The '+ 0ull' is needed for 'signed long long'.

Link: https://lkml.kernel.org/r/b97faef60ad24922b530241c5d7c933c@AcuMS.aculab.com
Link: https://lkml.kernel.org/r/41d93ca827a248698ec64bf57e0c05a5@AcuMS.aculab.com
Signed-off-by: David Laight &lt;david.laight@aculab.com&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Christoph Hellwig &lt;hch@infradead.org&gt;
Cc: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>minmax: fix header inclusions</title>
<updated>2023-10-04T17:41:57Z</updated>
<author>
<name>Andy Shevchenko</name>
<email>andriy.shevchenko@linux.intel.com</email>
</author>
<published>2023-09-12T09:23:55Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=f6e9d38f8eb00ac8b52e6d15f6aa9bcecacb081b'/>
<id>urn:sha1:f6e9d38f8eb00ac8b52e6d15f6aa9bcecacb081b</id>
<content type='text'>
BUILD_BUG_ON*() macros are defined in build_bug.h.  Include it.  Replace
compiler_types.h by compiler.h, which provides the former, to have a
definition of the __UNIQUE_ID().

Link: https://lkml.kernel.org/r/20230912092355.79280-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Reviewed-by: Herve Codina &lt;herve.codina@bootlin.com&gt;
Cc: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;

Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>minmax: deduplicate __unconst_integer_typeof()</title>
<updated>2023-10-04T17:41:57Z</updated>
<author>
<name>Andy Shevchenko</name>
<email>andriy.shevchenko@linux.intel.com</email>
</author>
<published>2023-09-11T15:49:13Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=5e57418a2031cd5e1863efdf3d7447a16a368172'/>
<id>urn:sha1:5e57418a2031cd5e1863efdf3d7447a16a368172</id>
<content type='text'>
It appears that compiler_types.h already have an implementation of the
__unconst_integer_typeof() called __unqual_scalar_typeof().  Use it
instead of the copy.

Link: https://lkml.kernel.org/r/20230911154913.4176033-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Acked-by: Herve Codina &lt;herve.codina@bootlin.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 'sound-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound</title>
<updated>2023-08-30T20:45:05Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-08-30T20:45:05Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=4fb0dacb78c6a041bbd38ddd998df806af5c2c69'/>
<id>urn:sha1:4fb0dacb78c6a041bbd38ddd998df806af5c2c69</id>
<content type='text'>
Pull sound updates from Takashi Iwai:
 "We've received a fairly wide range of changes at this time, including
  for ALSA and ASoC core, but all of them are rather small changes.

  Here are some highlights:

  ALSA / ASoC Core:
   - Fixes of inconsistent locking around control API helpers
   - A few new control API functions and cleanups
   - Workarounds for potential UAFs by delayed kobj releases
   - Unified PCM copy ops with iov_iter
   - Continued efforts for ASoC API cleanups

  ASoC:
   - An adaptor to allow use of IIO DACs and ADCs in ASoC which pulls in
     some IIO changes
   - Create a library function for intlog10() and use it in the NAU8825
     driver
   - Convert drivers to use the more modern maple tree register cache
   - Lots of work on the SOF framework, AMD and Intel drivers, including
     a lot of cleanup and new device support
   - Standardization of the presentation of jacks from drivers
   - Provision of some generic sound card DT properties
   - Support for AMD Van Gogh, AMD machines with MAX98388 and NAU8821,
     AWInic AW88261, Cirrus Logic CS35L36 and CS42L43, various Intel
     platforms including AVS machines with ES8336 and RT5663, Mediatek
     MT7986, NXP i.MX93, RealTek RT1017 and StarFive JH7110

  Others:
   - New test coverage including ASoC and topology tests in KUnit; this
     also involves enabling UML builds of ALSA since that's the default
     KUnit test environment which pulls in the addition of some stubs to
     the driver
   - More enhancement of pcmtest driver
   - A few fixes / enhancements of MIDI 2.0 UMP core
   - Using PCI definitions in allover HD-audio code
   - Support for Cirrus CS35L56 and TI TAS2781 HD-audio sub-codecs
   - CS35L41 HD-audio sub-codec improvements
   - Continued emu10k1 improvements"

* tag 'sound-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (693 commits)
  ALSA: pcm: Fix missing fixup call in compat hw_refine ioctl
  ASoC: dwc: i2s: Fix unused functions
  ALSA: usb-audio: Don't try to submit URBs after disconnection
  ALSA: emu10k1: add separate documentation for E-MU cards
  ALSA: emu10k1: more documentation updates
  ALSA: emu10k1: de-duplicate audigy-mixer.rst vs. sb-live-mixer.rst
  ALSA: ump: Fix -Wformat-truncation warnings
  ALSA: hda: Add missing dependency on CONFIG_EFI for Cirrus/TI sub-codecs
  ALSA: doc: Fix missing backquote in midi-2.0.rst
  ALSA: hda/realtek: Add quirk for mute LEDs on HP ENVY x360 15-eu0xxx
  ALSA: hda/tas2781: Switch back to use struct i2c_driver's .probe()
  ASoC: soc-core.c: Do not error if a DAI link component is not found
  ASoC: codecs: Fix error code in aw88261_i2c_probe()
  ASoC: audio-graph-card.c: move audio_graph_parse_of()
  ASoC: cs42l43: Use new-style PM runtime macros
  ALSA: documentation: Add description for USB MIDI 2.0 gadget driver
  ALSA: ump: Don't create unused substreams for static blocks
  ALSA: ump: Fill group names for legacy rawmidi substreams
  ALSA: usb-audio: Attach legacy rawmidi after probing all UMP EPs
  ALSA: ac97: Fix possible error value of *rac97
  ...
</content>
</entry>
<entry>
<title>minmax: add in_range() macro</title>
<updated>2023-08-24T23:20:18Z</updated>
<author>
<name>Matthew Wilcox (Oracle)</name>
<email>willy@infradead.org</email>
</author>
<published>2023-08-02T15:13:29Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=f9bff0e31881d03badf191d3b0005839391f5f2b'/>
<id>urn:sha1:f9bff0e31881d03badf191d3b0005839391f5f2b</id>
<content type='text'>
Patch series "New page table range API", v6.

This patchset changes the API used by the MM to set up page table entries.
The four APIs are:

    set_ptes(mm, addr, ptep, pte, nr)
    update_mmu_cache_range(vma, addr, ptep, nr)
    flush_dcache_folio(folio) 
    flush_icache_pages(vma, page, nr)

flush_dcache_folio() isn't technically new, but no architecture
implemented it, so I've done that for them.  The old APIs remain around
but are mostly implemented by calling the new interfaces.

The new APIs are based around setting up N page table entries at once. 
The N entries belong to the same PMD, the same folio and the same VMA, so
ptep++ is a legitimate operation, and locking is taken care of for you. 
Some architectures can do a better job of it than just a loop, but I have
hesitated to make too deep a change to architectures I don't understand
well.

One thing I have changed in every architecture is that PG_arch_1 is now a
per-folio bit instead of a per-page bit when used for dcache clean/dirty
tracking.  This was something that would have to happen eventually, and it
makes sense to do it now rather than iterate over every page involved in a
cache flush and figure out if it needs to happen.

The point of all this is better performance, and Fengwei Yin has measured
improvement on x86.  I suspect you'll see improvement on your architecture
too.  Try the new will-it-scale test mentioned here:
https://lore.kernel.org/linux-mm/20230206140639.538867-5-fengwei.yin@intel.com/
You'll need to run it on an XFS filesystem and have
CONFIG_TRANSPARENT_HUGEPAGE set.

This patchset is the basis for much of the anonymous large folio work
being done by Ryan, so it's received quite a lot of testing over the last
few months.


This patch (of 38):

Determine if a value lies within a range more efficiently (subtraction +
comparison vs two comparisons and an AND).  It also has useful (under some
circumstances) behaviour if the range exceeds the maximum value of the
type.  Convert all the conflicting definitions of in_range() within the
kernel; some can use the generic definition while others need their own
definition.

Link: https://lkml.kernel.org/r/20230802151406.3735276-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230802151406.3735276-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>minmax: Introduce {min,max}_array()</title>
<updated>2023-07-09T21:48:14Z</updated>
<author>
<name>Herve Codina</name>
<email>herve.codina@bootlin.com</email>
</author>
<published>2023-06-23T08:58:24Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=c952c748c7a983a8bda9112984e6f2c1f6e441a5'/>
<id>urn:sha1:c952c748c7a983a8bda9112984e6f2c1f6e441a5</id>
<content type='text'>
Introduce min_array() (resp max_array()) in order to get the
minimal (resp maximum) of values present in an array.

Signed-off-by: Herve Codina &lt;herve.codina@bootlin.com&gt;
Reviewed-by: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Reviewed-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Link: https://lore.kernel.org/r/20230623085830.749991-8-herve.codina@bootlin.com
Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
</content>
</entry>
</feed>
