<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/include/linux, branch v6.3-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4</title>
<updated>2023-03-12T15:55:55+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-03-12T15:55:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=40d0c0901e6c19cf268d2f505bce0b50319c5653'/>
<id>40d0c0901e6c19cf268d2f505bce0b50319c5653</id>
<content type='text'>
Pull ext4 fixes from Ted Ts'o:
 "Bug fixes and regressions for ext4, the most serious of which is a
  potential deadlock during directory renames that was introduced during
  the merge window discovered by a combination of syzbot and lockdep"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: zero i_disksize when initializing the bootloader inode
  ext4: make sure fs error flag setted before clear journal error
  ext4: commit super block if fs record error when journal record without error
  ext4, jbd2: add an optimized bmap for the journal inode
  ext4: fix WARNING in ext4_update_inline_data
  ext4: move where set the MAY_INLINE_DATA flag is set
  ext4: Fix deadlock during directory rename
  ext4: Fix comment about the 64BIT feature
  docs: ext4: modify the group desc size to 64
  ext4: fix another off-by-one fsmap error on 1k block filesystems
  ext4: fix RENAME_WHITEOUT handling for inline directories
  ext4: make kobj_type structures constant
  ext4: fix cgroup writeback accounting with fs-layer encryption
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull ext4 fixes from Ted Ts'o:
 "Bug fixes and regressions for ext4, the most serious of which is a
  potential deadlock during directory renames that was introduced during
  the merge window discovered by a combination of syzbot and lockdep"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: zero i_disksize when initializing the bootloader inode
  ext4: make sure fs error flag setted before clear journal error
  ext4: commit super block if fs record error when journal record without error
  ext4, jbd2: add an optimized bmap for the journal inode
  ext4: fix WARNING in ext4_update_inline_data
  ext4: move where set the MAY_INLINE_DATA flag is set
  ext4: Fix deadlock during directory rename
  ext4: Fix comment about the 64BIT feature
  docs: ext4: modify the group desc size to 64
  ext4: fix another off-by-one fsmap error on 1k block filesystems
  ext4: fix RENAME_WHITEOUT handling for inline directories
  ext4: make kobj_type structures constant
  ext4: fix cgroup writeback accounting with fs-layer encryption
</pre>
</div>
</content>
</entry>
<entry>
<title>cpumask: relax sanity checking constraints</title>
<updated>2023-03-12T15:52:03+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-03-12T15:52:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e7304080e0e50d979ce9eaf694ad8283e2e539ea'/>
<id>e7304080e0e50d979ce9eaf694ad8283e2e539ea</id>
<content type='text'>
The cpumask_check() was unnecessarily tight, and causes problems for the
users of cpumask_next().

We have a number of users that take the previous return value of one of
the bit scanning functions and subtract one to keep it in "range".  But
since the scanning functions end up returning up to 'small_cpumask_bits'
instead of the tighter 'nr_cpumask_bits', the range really needs to be
using that widened form.

[ This "previous-1" behavior is also the reason we have all those
  comments about /* -1 is a legal arg here. */ and separate checks for
  that being ok.  So we could have just made "small_cpumask_bits-1"
  be a similar special "don't check this" value.

  Tetsuo Handa even suggested a patch that only does that for
  cpumask_next(), since that seems to be the only actual case that
  triggers, but that all makes it even _more_ magical and special. So
  just relax the check ]

One example of this kind of pattern being the 'c_start()' function in
arch/x86/kernel/cpu/proc.c, but also duplicated in various forms on
other architectures.

Reported-by: syzbot+96cae094d90877641f32@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=96cae094d90877641f32
Reported-by: Tetsuo Handa &lt;penguin-kernel@i-love.sakura.ne.jp&gt;
Link: https://lore.kernel.org/lkml/c1f4cc16-feea-b83c-82cf-1a1f007b7eb9@I-love.SAKURA.ne.jp/
Fixes: 596ff4a09b89 ("cpumask: re-introduce constant-sized cpumask optimizations")
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The cpumask_check() was unnecessarily tight, and causes problems for the
users of cpumask_next().

We have a number of users that take the previous return value of one of
the bit scanning functions and subtract one to keep it in "range".  But
since the scanning functions end up returning up to 'small_cpumask_bits'
instead of the tighter 'nr_cpumask_bits', the range really needs to be
using that widened form.

[ This "previous-1" behavior is also the reason we have all those
  comments about /* -1 is a legal arg here. */ and separate checks for
  that being ok.  So we could have just made "small_cpumask_bits-1"
  be a similar special "don't check this" value.

  Tetsuo Handa even suggested a patch that only does that for
  cpumask_next(), since that seems to be the only actual case that
  triggers, but that all makes it even _more_ magical and special. So
  just relax the check ]

One example of this kind of pattern being the 'c_start()' function in
arch/x86/kernel/cpu/proc.c, but also duplicated in various forms on
other architectures.

Reported-by: syzbot+96cae094d90877641f32@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=96cae094d90877641f32
Reported-by: Tetsuo Handa &lt;penguin-kernel@i-love.sakura.ne.jp&gt;
Link: https://lore.kernel.org/lkml/c1f4cc16-feea-b83c-82cf-1a1f007b7eb9@I-love.SAKURA.ne.jp/
Fixes: 596ff4a09b89 ("cpumask: re-introduce constant-sized cpumask optimizations")
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'i2c-for-6.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux</title>
<updated>2023-03-11T17:24:05+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-03-11T17:24:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=81ff855485a366a391dc3aed3942715e676ed132'/>
<id>81ff855485a366a391dc3aed3942715e676ed132</id>
<content type='text'>
Pull i2c updates from Wolfram Sang:
 "This marks the end of a transition to let I2C have the same probe
  semantics as other subsystems. Uwe took care that no drivers in the
  current tree nor in -next use the deprecated .probe call. So, it is a
  good time to switch to the new, standard semantics now.

  There is also a regression fix:

   - regression fix for the notifier handling of the I2C core

   - final coversions of drivers away from deprecated .probe

   - make .probe_new the standard probe and convert I2C core to use it

* tag 'i2c-for-6.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: dev: Fix bus callback return values
  i2c: Convert drivers to new .probe() callback
  i2c: mux: Convert all drivers to new .probe() callback
  i2c: Switch .probe() to not take an id parameter
  media: i2c: ov2685: convert to i2c's .probe_new()
  media: i2c: ov5695: convert to i2c's .probe_new()
  w1: ds2482: Convert to i2c's .probe_new()
  serial: sc16is7xx: Convert to i2c's .probe_new()
  mtd: maps: pismo: Convert to i2c's .probe_new()
  misc: ad525x_dpot-i2c: Convert to i2c's .probe_new()
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull i2c updates from Wolfram Sang:
 "This marks the end of a transition to let I2C have the same probe
  semantics as other subsystems. Uwe took care that no drivers in the
  current tree nor in -next use the deprecated .probe call. So, it is a
  good time to switch to the new, standard semantics now.

  There is also a regression fix:

   - regression fix for the notifier handling of the I2C core

   - final coversions of drivers away from deprecated .probe

   - make .probe_new the standard probe and convert I2C core to use it

* tag 'i2c-for-6.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: dev: Fix bus callback return values
  i2c: Convert drivers to new .probe() callback
  i2c: mux: Convert all drivers to new .probe() callback
  i2c: Switch .probe() to not take an id parameter
  media: i2c: ov2685: convert to i2c's .probe_new()
  media: i2c: ov5695: convert to i2c's .probe_new()
  w1: ds2482: Convert to i2c's .probe_new()
  serial: sc16is7xx: Convert to i2c's .probe_new()
  mtd: maps: pismo: Convert to i2c's .probe_new()
  misc: ad525x_dpot-i2c: Convert to i2c's .probe_new()
</pre>
</div>
</content>
</entry>
<entry>
<title>ext4, jbd2: add an optimized bmap for the journal inode</title>
<updated>2023-03-11T05:44:24+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2023-03-08T04:15:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=62913ae96de747091c4dacd06d158e7729c1a76d'/>
<id>62913ae96de747091c4dacd06d158e7729c1a76d</id>
<content type='text'>
The generic bmap() function exported by the VFS takes locks and does
checks that are not necessary for the journal inode.  So allow the
file system to set a journal-optimized bmap function in
journal-&gt;j_bmap.

Reported-by: syzbot+9543479984ae9e576000@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=e4aaa78795e490421c79f76ec3679006c8ff4cf0
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The generic bmap() function exported by the VFS takes locks and does
checks that are not necessary for the journal inode.  So allow the
file system to set a journal-optimized bmap function in
journal-&gt;j_bmap.

Reported-by: syzbot+9543479984ae9e576000@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=e4aaa78795e490421c79f76ec3679006c8ff4cf0
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'pull-highmem' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs</title>
<updated>2023-03-11T03:09:18+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-03-11T03:09:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d33d4c9e0888e9ee7666813b3f9ecc244a64d127'/>
<id>d33d4c9e0888e9ee7666813b3f9ecc244a64d127</id>
<content type='text'>
Pull put_and_unmap_page() helper from Al Viro:
 "kmap_local_page() conversions in local filesystems keep running into
  kunmap_local_page()+put_page() combinations.  We can keep inventing
  names for identical inline helpers, but it's getting rather
  inconvenient. I've added a trivial helper to linux/highmem.h instead.

  I would've held that back until the merge window, if not for the mess
  it causes in tree topology - I've several branches merging from that
  one, and it's only going to get worse if e.g. ext2 stuff gets picked
  by Jan"

* tag 'pull-highmem' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  new helper: put_and_unmap_page()
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull put_and_unmap_page() helper from Al Viro:
 "kmap_local_page() conversions in local filesystems keep running into
  kunmap_local_page()+put_page() combinations.  We can keep inventing
  names for identical inline helpers, but it's getting rather
  inconvenient. I've added a trivial helper to linux/highmem.h instead.

  I would've held that back until the merge window, if not for the mess
  it causes in tree topology - I've several branches merging from that
  one, and it's only going to get worse if e.g. ext2 stuff gets picked
  by Jan"

* tag 'pull-highmem' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  new helper: put_and_unmap_page()
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: Switch .probe() to not take an id parameter</title>
<updated>2023-03-09T20:59:11+00:00</updated>
<author>
<name>Uwe Kleine-König</name>
<email>u.kleine-koenig@pengutronix.de</email>
</author>
<published>2023-02-26T22:26:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=03c835f498b540087244a6757e87dfe7ef10999b'/>
<id>03c835f498b540087244a6757e87dfe7ef10999b</id>
<content type='text'>
Commit b8a1a4cd5a98 ("i2c: Provide a temporary .probe_new() call-back
type") introduced a new probe callback to convert i2c init routines to
not take an i2c_device_id parameter. Now that all in-tree drivers are
converted to the temporary .probe_new() callback, .probe() can be
modified to match the desired prototype.

Now that .probe() and .probe_new() have the same semantic, they can be
defined as members of an anonymous union to save some memory and
simplify the core code a bit.

Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@pengutronix.de&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit b8a1a4cd5a98 ("i2c: Provide a temporary .probe_new() call-back
type") introduced a new probe callback to convert i2c init routines to
not take an i2c_device_id parameter. Now that all in-tree drivers are
converted to the temporary .probe_new() callback, .probe() can be
modified to match the desired prototype.

Now that .probe() and .probe_new() have the same semantic, they can be
defined as members of an anonymous union to save some memory and
simplify the core code a bit.

Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@pengutronix.de&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus-2023030901' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid</title>
<updated>2023-03-09T18:17:23+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-03-09T18:17:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2653e3fe33f411227296552b2e5f9c2640924900'/>
<id>2653e3fe33f411227296552b2e5f9c2640924900</id>
<content type='text'>
Pull HID fixes from Benjamin Tissoires:

 - fix potential out of bound write of zeroes in HID core with a
   specially crafted uhid device (Lee Jones)

 - fix potential use-after-free in work function in intel-ish-hid (Reka
   Norman)

 - selftests config fixes (Benjamin Tissoires)

 - few device small fixes and support

* tag 'for-linus-2023030901' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid:
  HID: intel-ish-hid: ipc: Fix potential use-after-free in work function
  HID: logitech-hidpp: Add support for Logitech MX Master 3S mouse
  HID: cp2112: Fix driver not registering GPIO IRQ chip as threaded
  selftest: hid: fix hid_bpf not set in config
  HID: uhid: Over-ride the default maximum data buffer value with our own
  HID: core: Provide new max_buffer_size attribute to over-ride the default
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull HID fixes from Benjamin Tissoires:

 - fix potential out of bound write of zeroes in HID core with a
   specially crafted uhid device (Lee Jones)

 - fix potential use-after-free in work function in intel-ish-hid (Reka
   Norman)

 - selftests config fixes (Benjamin Tissoires)

 - few device small fixes and support

* tag 'for-linus-2023030901' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid:
  HID: intel-ish-hid: ipc: Fix potential use-after-free in work function
  HID: logitech-hidpp: Add support for Logitech MX Master 3S mouse
  HID: cp2112: Fix driver not registering GPIO IRQ chip as threaded
  selftest: hid: fix hid_bpf not set in config
  HID: uhid: Over-ride the default maximum data buffer value with our own
  HID: core: Provide new max_buffer_size attribute to over-ride the default
</pre>
</div>
</content>
</entry>
<entry>
<title>cpumask: be more careful with 'cpumask_setall()'</title>
<updated>2023-03-07T20:16:18+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-03-07T20:16:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=63355b9884b3d1677de6bd1517cd2b8a9bf53978'/>
<id>63355b9884b3d1677de6bd1517cd2b8a9bf53978</id>
<content type='text'>
Commit 596ff4a09b89 ("cpumask: re-introduce constant-sized cpumask
optimizations") changed cpumask_setall() to use "bitmap_set()" instead
of "bitmap_fill()", because bitmap_fill() would explicitly set all the
bits of a constant sized small bitmap, and that's exactly what we don't
want: we want to only set bits up to 'nr_cpu_ids', which is what
"bitmap_set()" does.

However, Yury correctly points out that while "bitmap_set()" does indeed
only set bits up to the required bitmap size, it doesn't _clear_ bits
above that size, so the upper bits would still not have well-defined
values.

Now, none of this should really matter, since any bits set past
'nr_cpu_ids' should always be ignored in the first place.  Yes, the bit
scanning functions might return them as a result, but since users should
always consider the "&gt;= nr_cpu_ids" condition to mean "no more bits",
that shouldn't have any actual effect (see previous commit 8ca09d5fa354
"cpumask: fix incorrect cpumask scanning result checks").

But let's just do it right, the way the code was _intended_ to work.  We
have had enough lazy code that works but bites us in the *rse later
(again, see previous commit) that there's no reason to not just do this
properly.

It turns out that "bitmap_fill()" gets this all right for the complex
case, and really only fails for the inlined optimized case that just
fills the whole word.  And while we could just fix bitmap_fill() to use
the proper last word mask, there's two issues with that:

 - the cpumask case wants to do the _optimization_ based on "NR_CPUS is
   a small constant", but then wants to do the actual bit _fill_ based
   on "nr_cpu_ids" that isn't necessarily that same constant

 - we have lots of non-cpumask users of bitmap_fill(), and while they
   hopefully don't care, and probably would want the proper semantics
   anyway ("only set bits up to the limit"), I do not want the cpumask
   changes to impact other parts

So this ends up just doing the single-word optimization by hand in the
cpumask code.  If our cpumask is fundamentally limited to a single word,
just do the proper "fill in that word" exactly.  And if it's the more
complex multi-word case, then the generic bitmap_fill() will DTRT.

This is all an example of how our bitmap function optimizations really
are somewhat broken.  They conflate the "this is size of the bitmap"
optimizations with the actual bit(s) we want to set.

In many cases we really want to have the two be separate things:
sometimes we base our optimizations on the size of the whole bitmap ("I
know this whole bitmap fits in a single word, so I'll just use
single-word accesses"), and sometimes we base them on the bit we are
looking at ("this is just acting on bits that are in the first word, so
I'll use single-word accesses").

Notice how the end result of the two optimizations are the same, but the
way we get to them are quite different.

And all our cpumask optimization games are really about that fundamental
distinction, and we'd often really want to pass in both the "this is the
bit I'm working on" (which _can_ be a small constant but might be
variable), and "I know it's in this range even if it's variable" (based
on CONFIG_NR_CPUS).

So this cpumask_setall() implementation just makes that explicit.  It
checks the "I statically know the size is small" using the known static
size of the cpumask (which is what that 'small_cpumask_bits' is all
about), but then sets the actual bits using the exact number of cpus we
have (ie 'nr_cpumask_bits')

Of course, in a perfect world, the compiler would have done all the
range analysis (possibly with help from us just telling it that
"this value is always in this range"), and would do all of this for us.
But that is not the world we live in.

While we dream of that perfect world, this does that manual logic to
make it all work out.  And this was a very long explanation for a small
code change that shouldn't even matter.

Reported-by: Yury Norov &lt;yury.norov@gmail.com&gt;
Link: https://lore.kernel.org/lkml/ZAV9nGG9e1%2FrV+L%2F@yury-laptop/
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 596ff4a09b89 ("cpumask: re-introduce constant-sized cpumask
optimizations") changed cpumask_setall() to use "bitmap_set()" instead
of "bitmap_fill()", because bitmap_fill() would explicitly set all the
bits of a constant sized small bitmap, and that's exactly what we don't
want: we want to only set bits up to 'nr_cpu_ids', which is what
"bitmap_set()" does.

However, Yury correctly points out that while "bitmap_set()" does indeed
only set bits up to the required bitmap size, it doesn't _clear_ bits
above that size, so the upper bits would still not have well-defined
values.

Now, none of this should really matter, since any bits set past
'nr_cpu_ids' should always be ignored in the first place.  Yes, the bit
scanning functions might return them as a result, but since users should
always consider the "&gt;= nr_cpu_ids" condition to mean "no more bits",
that shouldn't have any actual effect (see previous commit 8ca09d5fa354
"cpumask: fix incorrect cpumask scanning result checks").

But let's just do it right, the way the code was _intended_ to work.  We
have had enough lazy code that works but bites us in the *rse later
(again, see previous commit) that there's no reason to not just do this
properly.

It turns out that "bitmap_fill()" gets this all right for the complex
case, and really only fails for the inlined optimized case that just
fills the whole word.  And while we could just fix bitmap_fill() to use
the proper last word mask, there's two issues with that:

 - the cpumask case wants to do the _optimization_ based on "NR_CPUS is
   a small constant", but then wants to do the actual bit _fill_ based
   on "nr_cpu_ids" that isn't necessarily that same constant

 - we have lots of non-cpumask users of bitmap_fill(), and while they
   hopefully don't care, and probably would want the proper semantics
   anyway ("only set bits up to the limit"), I do not want the cpumask
   changes to impact other parts

So this ends up just doing the single-word optimization by hand in the
cpumask code.  If our cpumask is fundamentally limited to a single word,
just do the proper "fill in that word" exactly.  And if it's the more
complex multi-word case, then the generic bitmap_fill() will DTRT.

This is all an example of how our bitmap function optimizations really
are somewhat broken.  They conflate the "this is size of the bitmap"
optimizations with the actual bit(s) we want to set.

In many cases we really want to have the two be separate things:
sometimes we base our optimizations on the size of the whole bitmap ("I
know this whole bitmap fits in a single word, so I'll just use
single-word accesses"), and sometimes we base them on the bit we are
looking at ("this is just acting on bits that are in the first word, so
I'll use single-word accesses").

Notice how the end result of the two optimizations are the same, but the
way we get to them are quite different.

And all our cpumask optimization games are really about that fundamental
distinction, and we'd often really want to pass in both the "this is the
bit I'm working on" (which _can_ be a small constant but might be
variable), and "I know it's in this range even if it's variable" (based
on CONFIG_NR_CPUS).

So this cpumask_setall() implementation just makes that explicit.  It
checks the "I statically know the size is small" using the known static
size of the cpumask (which is what that 'small_cpumask_bits' is all
about), but then sets the actual bits using the exact number of cpus we
have (ie 'nr_cpumask_bits')

Of course, in a perfect world, the compiler would have done all the
range analysis (possibly with help from us just telling it that
"this value is always in this range"), and would do all of this for us.
But that is not the world we live in.

While we dream of that perfect world, this does that manual logic to
make it all work out.  And this was a very long explanation for a small
code change that shouldn't even matter.

Reported-by: Yury Norov &lt;yury.norov@gmail.com&gt;
Link: https://lore.kernel.org/lkml/ZAV9nGG9e1%2FrV+L%2F@yury-laptop/
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>new helper: put_and_unmap_page()</title>
<updated>2023-03-07T06:50:53+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2023-03-07T06:50:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=849ad04cf562ac63b0371a825eed473d84de9c6d'/>
<id>849ad04cf562ac63b0371a825eed473d84de9c6d</id>
<content type='text'>
kunmap_local() + put_page(), as done by e.g. ext2 directory handling.

Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
kunmap_local() + put_page(), as done by e.g. ext2 directory handling.

Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpumask: Fix typo nr_cpumask_size --&gt; nr_cpumask_bits</title>
<updated>2023-03-06T18:58:04+00:00</updated>
<author>
<name>Andy Shevchenko</name>
<email>andriy.shevchenko@linux.intel.com</email>
</author>
<published>2023-03-06T15:22:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=80c16b2b121fbc3380dbffa9bab7559acbaaa2ed'/>
<id>80c16b2b121fbc3380dbffa9bab7559acbaaa2ed</id>
<content type='text'>
The never used nr_cpumask_size is just a typo, hence use existing
redefinition that's called nr_cpumask_bits.

Signed-off-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The never used nr_cpumask_size is just a typo, hence use existing
redefinition that's called nr_cpumask_bits.

Signed-off-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
