[PATCH v3 00/23] Fix some issues at documentation

[PATCH v3 00/23] Fix some issues at documentation

[Mauro Carvalho Chehab]

Hi Jon,

This series is against today's next (next-20211019) and addresses missing
links to Documentation/*.

The best would be to have the patches applied directly to the trees that
contain the patches that moved/renamed files, and then apply the
remaining ones either later during the merge window or just afterwards,
whatever works best for you.

Regards,
Mauro

Mauro Carvalho Chehab (23):
  visorbus: fix a copyright symbol that was bad encoded
  libbpf: update index.rst reference
  docs: accounting: update delay-accounting.rst reference
  MAINTAINERS: update arm,vic.yaml reference
  MAINTAINERS: update aspeed,i2c.yaml reference
  MAINTAINERS: update faraday,ftrtc010.yaml reference
  MAINTAINERS: update ti,sci.yaml reference
  MAINTAINERS: update intel,ixp46x-rng.yaml reference
  MAINTAINERS: update nxp,imx8-jpeg.yaml reference
  MAINTAINERS: update gemini.yaml reference
  MAINTAINERS: update brcm,unimac-mdio.yaml reference
  MAINTAINERS: update mtd-physmap.yaml reference
  Documentation: update vcpu-requests.rst reference
  bpftool: update bpftool-cgroup.rst reference
  docs: translations: zn_CN: irq-affinity.rst: add a missing extension
  docs: translations: zh_CN: memory-hotplug.rst: fix a typo
  docs: fs: locks.rst: update comment about mandatory file locking
  fs: remove a comment pointing to the removed mandatory-locking file
  Documentation/process: fix a cross reference
  dt-bindings: mfd: update x-powers,axp152.yaml reference
  regulator: dt-bindings: update samsung,s2mpa01.yaml reference
  regulator: dt-bindings: update samsung,s5m8767.yaml reference
  dt-bindings: reserved-memory: ramoops: update ramoops.yaml references

 Documentation/admin-guide/ramoops.rst         |  2 +-
 Documentation/admin-guide/sysctl/kernel.rst   |  2 +-
 Documentation/bpf/index.rst                   |  2 +-
 .../devicetree/bindings/gpio/gpio-axp209.txt  |  2 +-
 .../bindings/regulator/samsung,s2mpa01.yaml   |  2 +-
 .../bindings/regulator/samsung,s5m8767.yaml   |  2 +-
 Documentation/filesystems/locks.rst           | 17 +++++-----------
 Documentation/process/submitting-patches.rst  |  4 ++--
 .../zh_CN/core-api/irq/irq-affinity.rst       |  2 +-
 .../zh_CN/core-api/memory-hotplug.rst         |  2 +-
 MAINTAINERS                                   | 20 +++++++++----------
 arch/riscv/kvm/vcpu.c                         |  2 +-
 drivers/visorbus/visorbus_main.c              |  2 +-
 fs/locks.c                                    |  1 -
 .../selftests/bpf/test_bpftool_synctypes.py   |  2 +-
 15 files changed, 28 insertions(+), 36 deletions(-)

-- 
2.31.1

[PATCH v3 18/23] fs: remove a comment pointing to the removed mandatory-locking file

[Mauro Carvalho Chehab]

The mandatory file locking got removed due to its problems, but
there's still a comment inside fs/locks.c pointing to the removed
doc.

Remove it.

Fixes: f7e33bdbd6d1 ("fs: remove mandatory file locking support")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---

To mailbombing on a large number of people, only mailing lists were C/C on the cover.
See [PATCH v3 00/23] at: https://lore.kernel.org/all/cover.1634630485.git.mchehab+huawei@kernel.org/

 fs/locks.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/locks.c b/fs/locks.c
index d397394633be..94feadcdab4e 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -61,7 +61,6 @@
  *
  *  Initial implementation of mandatory locks. SunOS turned out to be
  *  a rotten model, so I implemented the "obvious" semantics.
- *  See 'Documentation/filesystems/mandatory-locking.rst' for details.
  *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
  *
  *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to
-- 
2.31.1

Re: [PATCH v3 18/23] fs: remove a comment pointing to the removed mandatory-locking file

[Jeff Layton]

On Tue, 2021-10-19 at 09:04 +0100, Mauro Carvalho Chehab wrote:
> The mandatory file locking got removed due to its problems, but
> there's still a comment inside fs/locks.c pointing to the removed
> doc.
> 
> Remove it.
> 
> Fixes: f7e33bdbd6d1 ("fs: remove mandatory file locking support")
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> ---
> 
> To mailbombing on a large number of people, only mailing lists were C/C on the cover.
> See [PATCH v3 00/23] at: https://lore.kernel.org/all/cover.1634630485.git.mchehab+huawei@kernel.org/
> 
>  fs/locks.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/fs/locks.c b/fs/locks.c
> index d397394633be..94feadcdab4e 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -61,7 +61,6 @@
>   *
>   *  Initial implementation of mandatory locks. SunOS turned out to be
>   *  a rotten model, so I implemented the "obvious" semantics.
> - *  See 'Documentation/filesystems/mandatory-locking.rst' for details.
>   *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
>   *
>   *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to

Thanks Mauro. I'll pick this into my locks branch, so it should make
v5.16 as well.
-- 
Jeff Layton <jlayton@kernel.org>

Re: [PATCH v3 18/23] fs: remove a comment pointing to the removed mandatory-locking file

[J. Bruce Fields]

On Tue, Oct 19, 2021 at 06:50:21AM -0400, Jeff Layton wrote:
> On Tue, 2021-10-19 at 09:04 +0100, Mauro Carvalho Chehab wrote:
> > The mandatory file locking got removed due to its problems, but
> > there's still a comment inside fs/locks.c pointing to the removed
> > doc.
> > 
> > Remove it.
> > 
> > Fixes: f7e33bdbd6d1 ("fs: remove mandatory file locking support")
> > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> > ---
> > 
> > To mailbombing on a large number of people, only mailing lists were C/C on the cover.
> > See [PATCH v3 00/23] at: https://lore.kernel.org/all/cover.1634630485.git.mchehab+huawei@kernel.org/
> > 
> >  fs/locks.c | 1 -
> >  1 file changed, 1 deletion(-)
> > 
> > diff --git a/fs/locks.c b/fs/locks.c
> > index d397394633be..94feadcdab4e 100644
> > --- a/fs/locks.c
> > +++ b/fs/locks.c
> > @@ -61,7 +61,6 @@
> >   *
> >   *  Initial implementation of mandatory locks. SunOS turned out to be
> >   *  a rotten model, so I implemented the "obvious" semantics.
> > - *  See 'Documentation/filesystems/mandatory-locking.rst' for details.
> >   *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
> >   *
> >   *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to
> 
> Thanks Mauro. I'll pick this into my locks branch, so it should make
> v5.16 as well.

Could we delete the rest too?

We don't do those changelog-style comments any more; they're in the git
history if you need them.  I can sort of get leaving some in out of
respect or if they've still provide some useful information.  But
keeping comments referring to code that doesn't even exist any more just
seems confusing.

--b.

diff --git a/fs/locks.c b/fs/locks.c
index 3d6fb4ae847b..2540b7aedeac 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -59,17 +59,6 @@
  *  once we've checked for blocking and deadlocking.
  *  Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
  *
- *  Initial implementation of mandatory locks. SunOS turned out to be
- *  a rotten model, so I implemented the "obvious" semantics.
- *  See 'Documentation/filesystems/mandatory-locking.rst' for details.
- *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
- *
- *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to
- *  check if a file has mandatory locks, used by mmap(), open() and creat() to
- *  see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
- *  Manual, Section 2.
- *  Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
- *
  *  Tidied up block list handling. Added '/proc/locks' interface.
  *  Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
  *
@@ -95,10 +84,6 @@
  *  Made the block list a circular list to minimise searching in the list.
  *  Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
  *
- *  Made mandatory locking a mount option. Default is not to allow mandatory
- *  locking.
- *  Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
- *
  *  Some adaptations for NFS support.
  *  Olaf Kirch (okir@monad.swb.de), Dec 1996,
  *

Re: [PATCH v3 18/23] fs: remove a comment pointing to the removed mandatory-locking file

[Jeff Layton]

On Tue, 2021-10-19 at 10:14 -0400, J. Bruce Fields wrote:
> On Tue, Oct 19, 2021 at 06:50:21AM -0400, Jeff Layton wrote:
> > On Tue, 2021-10-19 at 09:04 +0100, Mauro Carvalho Chehab wrote:
> > > The mandatory file locking got removed due to its problems, but
> > > there's still a comment inside fs/locks.c pointing to the removed
> > > doc.
> > > 
> > > Remove it.
> > > 
> > > Fixes: f7e33bdbd6d1 ("fs: remove mandatory file locking support")
> > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> > > ---
> > > 
> > > To mailbombing on a large number of people, only mailing lists were C/C on the cover.
> > > See [PATCH v3 00/23] at: https://lore.kernel.org/all/cover.1634630485.git.mchehab+huawei@kernel.org/
> > > 
> > >  fs/locks.c | 1 -
> > >  1 file changed, 1 deletion(-)
> > > 
> > > diff --git a/fs/locks.c b/fs/locks.c
> > > index d397394633be..94feadcdab4e 100644
> > > --- a/fs/locks.c
> > > +++ b/fs/locks.c
> > > @@ -61,7 +61,6 @@
> > >   *
> > >   *  Initial implementation of mandatory locks. SunOS turned out to be
> > >   *  a rotten model, so I implemented the "obvious" semantics.
> > > - *  See 'Documentation/filesystems/mandatory-locking.rst' for details.
> > >   *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
> > >   *
> > >   *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to
> > 
> > Thanks Mauro. I'll pick this into my locks branch, so it should make
> > v5.16 as well.
> 
> Could we delete the rest too?
> 
> We don't do those changelog-style comments any more; they're in the git
> history if you need them.  I can sort of get leaving some in out of
> respect or if they've still provide some useful information.  But
> keeping comments referring to code that doesn't even exist any more just
> seems confusing.
> 
> --b.
> 
> diff --git a/fs/locks.c b/fs/locks.c
> index 3d6fb4ae847b..2540b7aedeac 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -59,17 +59,6 @@
>   *  once we've checked for blocking and deadlocking.
>   *  Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
>   *
> - *  Initial implementation of mandatory locks. SunOS turned out to be
> - *  a rotten model, so I implemented the "obvious" semantics.
> - *  See 'Documentation/filesystems/mandatory-locking.rst' for details.
> - *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
> - *
> - *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to
> - *  check if a file has mandatory locks, used by mmap(), open() and creat() to
> - *  see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
> - *  Manual, Section 2.
> - *  Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
> - *
>   *  Tidied up block list handling. Added '/proc/locks' interface.
>   *  Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
>   *
> @@ -95,10 +84,6 @@
>   *  Made the block list a circular list to minimise searching in the list.
>   *  Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
>   *
> - *  Made mandatory locking a mount option. Default is not to allow mandatory
> - *  locking.
> - *  Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
> - *
>   *  Some adaptations for NFS support.
>   *  Olaf Kirch (okir@monad.swb.de), Dec 1996,
>   *

IDK...Do we want to "erase history" selectively like that?

Maybe we should just get rid of the whole pile of "changelog" comments
in fs/locks.c? They aren't terribly useful these days anyhow.

-- 
Jeff Layton <jlayton@kernel.org>

Re: [PATCH v3 18/23] fs: remove a comment pointing to the removed mandatory-locking file

[J. Bruce Fields]

On Tue, Oct 19, 2021 at 11:46:51AM -0400, Jeff Layton wrote:
> IDK...Do we want to "erase history" selectively like that?

Seems like pretty spotty history anyway, so I don't think it's a
problem, but...

> Maybe we should just get rid of the whole pile of "changelog" comments
> in fs/locks.c? They aren't terribly useful these days anyhow.

...  that'd be fine with me.

I didn't mainly because I thought it'd be good to read through it and
see if there's anything that should be salvaged.

Reading through it now:

The last few paragraphs (under "Locking conflicts and dependencies" were
added more recently by Neil and are still useful.

I'd be OK losing the rest.

It might still be good to have some basic introduction; maybe something
like this?:

--b.

diff --git a/fs/locks.c b/fs/locks.c
index 3d6fb4ae847b..b54813eae44f 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2,117 +2,11 @@
 /*
  *  linux/fs/locks.c
  *
- *  Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
- *  Doug Evans (dje@spiff.uucp), August 07, 1992
+ * We implement four types of file locks: BSD locks, posix locks, open
+ * file description locks, and leases.  For details about BSD locks,
+ * see the flock(2) man page; for details about the other three, see
+ * fcntl(2).
  *
- *  Deadlock detection added.
- *  FIXME: one thing isn't handled yet:
- *	- mandatory locks (requires lots of changes elsewhere)
- *  Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994.
- *
- *  Miscellaneous edits, and a total rewrite of posix_lock_file() code.
- *  Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994
- *
- *  Converted file_lock_table to a linked list from an array, which eliminates
- *  the limits on how many active file locks are open.
- *  Chad Page (pageone@netcom.com), November 27, 1994
- *
- *  Removed dependency on file descriptors. dup()'ed file descriptors now
- *  get the same locks as the original file descriptors, and a close() on
- *  any file descriptor removes ALL the locks on the file for the current
- *  process. Since locks still depend on the process id, locks are inherited
- *  after an exec() but not after a fork(). This agrees with POSIX, and both
- *  BSD and SVR4 practice.
- *  Andy Walker (andy@lysaker.kvaerner.no), February 14, 1995
- *
- *  Scrapped free list which is redundant now that we allocate locks
- *  dynamically with kmalloc()/kfree().
- *  Andy Walker (andy@lysaker.kvaerner.no), February 21, 1995
- *
- *  Implemented two lock personalities - FL_FLOCK and FL_POSIX.
- *
- *  FL_POSIX locks are created with calls to fcntl() and lockf() through the
- *  fcntl() system call. They have the semantics described above.
- *
- *  FL_FLOCK locks are created with calls to flock(), through the flock()
- *  system call, which is new. Old C libraries implement flock() via fcntl()
- *  and will continue to use the old, broken implementation.
- *
- *  FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated
- *  with a file pointer (filp). As a result they can be shared by a parent
- *  process and its children after a fork(). They are removed when the last
- *  file descriptor referring to the file pointer is closed (unless explicitly
- *  unlocked).
- *
- *  FL_FLOCK locks never deadlock, an existing lock is always removed before
- *  upgrading from shared to exclusive (or vice versa). When this happens
- *  any processes blocked by the current lock are woken up and allowed to
- *  run before the new lock is applied.
- *  Andy Walker (andy@lysaker.kvaerner.no), June 09, 1995
- *
- *  Removed some race conditions in flock_lock_file(), marked other possible
- *  races. Just grep for FIXME to see them.
- *  Dmitry Gorodchanin (pgmdsg@ibi.com), February 09, 1996.
- *
- *  Addressed Dmitry's concerns. Deadlock checking no longer recursive.
- *  Lock allocation changed to GFP_ATOMIC as we can't afford to sleep
- *  once we've checked for blocking and deadlocking.
- *  Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
- *
- *  Initial implementation of mandatory locks. SunOS turned out to be
- *  a rotten model, so I implemented the "obvious" semantics.
- *  See 'Documentation/filesystems/mandatory-locking.rst' for details.
- *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
- *
- *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to
- *  check if a file has mandatory locks, used by mmap(), open() and creat() to
- *  see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
- *  Manual, Section 2.
- *  Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
- *
- *  Tidied up block list handling. Added '/proc/locks' interface.
- *  Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
- *
- *  Fixed deadlock condition for pathological code that mixes calls to
- *  flock() and fcntl().
- *  Andy Walker (andy@lysaker.kvaerner.no), April 29, 1996.
- *
- *  Allow only one type of locking scheme (FL_POSIX or FL_FLOCK) to be in use
- *  for a given file at a time. Changed the CONFIG_LOCK_MANDATORY scheme to
- *  guarantee sensible behaviour in the case where file system modules might
- *  be compiled with different options than the kernel itself.
- *  Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
- *
- *  Added a couple of missing wake_up() calls. Thanks to Thomas Meckel
- *  (Thomas.Meckel@mni.fh-giessen.de) for spotting this.
- *  Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
- *
- *  Changed FL_POSIX locks to use the block list in the same way as FL_FLOCK
- *  locks. Changed process synchronisation to avoid dereferencing locks that
- *  have already been freed.
- *  Andy Walker (andy@lysaker.kvaerner.no), Sep 21, 1996.
- *
- *  Made the block list a circular list to minimise searching in the list.
- *  Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
- *
- *  Made mandatory locking a mount option. Default is not to allow mandatory
- *  locking.
- *  Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
- *
- *  Some adaptations for NFS support.
- *  Olaf Kirch (okir@monad.swb.de), Dec 1996,
- *
- *  Fixed /proc/locks interface so that we can't overrun the buffer we are handed.
- *  Andy Walker (andy@lysaker.kvaerner.no), May 12, 1997.
- *
- *  Use slab allocator instead of kmalloc/kfree.
- *  Use generic list implementation from <linux/list.h>.
- *  Sped up posix_locks_deadlock by only considering blocked locks.
- *  Matthew Wilcox <willy@debian.org>, March, 2000.
- *
- *  Leases and LOCK_MAND
- *  Matthew Wilcox <willy@debian.org>, June, 2000.
- *  Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
  *
  * Locking conflicts and dependencies:
  * If multiple threads attempt to lock the same byte (or flock the same file)

Re: [PATCH v3 18/23] fs: remove a comment pointing to the removed mandatory-locking file

[Jeff Layton]

On Tue, 2021-10-19 at 12:16 -0400, J. Bruce Fields wrote:
> On Tue, Oct 19, 2021 at 11:46:51AM -0400, Jeff Layton wrote:
> > IDK...Do we want to "erase history" selectively like that?
> 
> Seems like pretty spotty history anyway, so I don't think it's a
> problem, but...
> 
> > Maybe we should just get rid of the whole pile of "changelog" comments
> > in fs/locks.c? They aren't terribly useful these days anyhow.
> 
> ...  that'd be fine with me.
> 
> I didn't mainly because I thought it'd be good to read through it and
> see if there's anything that should be salvaged.
> 
> Reading through it now:
> 
> The last few paragraphs (under "Locking conflicts and dependencies" were
> added more recently by Neil and are still useful.
> 
> I'd be OK losing the rest.
> 
> It might still be good to have some basic introduction; maybe something
> like this?:
> 
> --b.
> 
> diff --git a/fs/locks.c b/fs/locks.c
> index 3d6fb4ae847b..b54813eae44f 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -2,117 +2,11 @@
>  /*
>   *  linux/fs/locks.c
>   *
> - *  Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
> - *  Doug Evans (dje@spiff.uucp), August 07, 1992
> + * We implement four types of file locks: BSD locks, posix locks, open
> + * file description locks, and leases.  For details about BSD locks,
> + * see the flock(2) man page; for details about the other three, see
> + * fcntl(2).
>   *
> - *  Deadlock detection added.
> - *  FIXME: one thing isn't handled yet:
> - *	- mandatory locks (requires lots of changes elsewhere)
> - *  Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994.
> - *
> - *  Miscellaneous edits, and a total rewrite of posix_lock_file() code.
> - *  Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994
> - *
> - *  Converted file_lock_table to a linked list from an array, which eliminates
> - *  the limits on how many active file locks are open.
> - *  Chad Page (pageone@netcom.com), November 27, 1994
> - *
> - *  Removed dependency on file descriptors. dup()'ed file descriptors now
> - *  get the same locks as the original file descriptors, and a close() on
> - *  any file descriptor removes ALL the locks on the file for the current
> - *  process. Since locks still depend on the process id, locks are inherited
> - *  after an exec() but not after a fork(). This agrees with POSIX, and both
> - *  BSD and SVR4 practice.
> - *  Andy Walker (andy@lysaker.kvaerner.no), February 14, 1995
> - *
> - *  Scrapped free list which is redundant now that we allocate locks
> - *  dynamically with kmalloc()/kfree().
> - *  Andy Walker (andy@lysaker.kvaerner.no), February 21, 1995
> - *
> - *  Implemented two lock personalities - FL_FLOCK and FL_POSIX.
> - *
> - *  FL_POSIX locks are created with calls to fcntl() and lockf() through the
> - *  fcntl() system call. They have the semantics described above.
> - *
> - *  FL_FLOCK locks are created with calls to flock(), through the flock()
> - *  system call, which is new. Old C libraries implement flock() via fcntl()
> - *  and will continue to use the old, broken implementation.
> - *
> - *  FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated
> - *  with a file pointer (filp). As a result they can be shared by a parent
> - *  process and its children after a fork(). They are removed when the last
> - *  file descriptor referring to the file pointer is closed (unless explicitly
> - *  unlocked).
> - *
> - *  FL_FLOCK locks never deadlock, an existing lock is always removed before
> - *  upgrading from shared to exclusive (or vice versa). When this happens
> - *  any processes blocked by the current lock are woken up and allowed to
> - *  run before the new lock is applied.
> - *  Andy Walker (andy@lysaker.kvaerner.no), June 09, 1995
> - *
> - *  Removed some race conditions in flock_lock_file(), marked other possible
> - *  races. Just grep for FIXME to see them.
> - *  Dmitry Gorodchanin (pgmdsg@ibi.com), February 09, 1996.
> - *
> - *  Addressed Dmitry's concerns. Deadlock checking no longer recursive.
> - *  Lock allocation changed to GFP_ATOMIC as we can't afford to sleep
> - *  once we've checked for blocking and deadlocking.
> - *  Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
> - *
> - *  Initial implementation of mandatory locks. SunOS turned out to be
> - *  a rotten model, so I implemented the "obvious" semantics.
> - *  See 'Documentation/filesystems/mandatory-locking.rst' for details.
> - *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
> - *
> - *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to
> - *  check if a file has mandatory locks, used by mmap(), open() and creat() to
> - *  see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
> - *  Manual, Section 2.
> - *  Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
> - *
> - *  Tidied up block list handling. Added '/proc/locks' interface.
> - *  Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
> - *
> - *  Fixed deadlock condition for pathological code that mixes calls to
> - *  flock() and fcntl().
> - *  Andy Walker (andy@lysaker.kvaerner.no), April 29, 1996.
> - *
> - *  Allow only one type of locking scheme (FL_POSIX or FL_FLOCK) to be in use
> - *  for a given file at a time. Changed the CONFIG_LOCK_MANDATORY scheme to
> - *  guarantee sensible behaviour in the case where file system modules might
> - *  be compiled with different options than the kernel itself.
> - *  Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
> - *
> - *  Added a couple of missing wake_up() calls. Thanks to Thomas Meckel
> - *  (Thomas.Meckel@mni.fh-giessen.de) for spotting this.
> - *  Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
> - *
> - *  Changed FL_POSIX locks to use the block list in the same way as FL_FLOCK
> - *  locks. Changed process synchronisation to avoid dereferencing locks that
> - *  have already been freed.
> - *  Andy Walker (andy@lysaker.kvaerner.no), Sep 21, 1996.
> - *
> - *  Made the block list a circular list to minimise searching in the list.
> - *  Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
> - *
> - *  Made mandatory locking a mount option. Default is not to allow mandatory
> - *  locking.
> - *  Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
> - *
> - *  Some adaptations for NFS support.
> - *  Olaf Kirch (okir@monad.swb.de), Dec 1996,
> - *
> - *  Fixed /proc/locks interface so that we can't overrun the buffer we are handed.
> - *  Andy Walker (andy@lysaker.kvaerner.no), May 12, 1997.
> - *
> - *  Use slab allocator instead of kmalloc/kfree.
> - *  Use generic list implementation from <linux/list.h>.
> - *  Sped up posix_locks_deadlock by only considering blocked locks.
> - *  Matthew Wilcox <willy@debian.org>, March, 2000.
> - *
> - *  Leases and LOCK_MAND
> - *  Matthew Wilcox <willy@debian.org>, June, 2000.
> - *  Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
>   *
>   * Locking conflicts and dependencies:
>   * If multiple threads attempt to lock the same byte (or flock the same file)

Yeah, I think that looks great. Send it with a changelog and I'll pull
it into the branch I have feeding into -next.

Thanks,
-- 
Jeff Layton <jlayton@kernel.org>

Re: [PATCH v3 00/23] Fix some issues at documentation

[Rob Herring]

On Tue, 19 Oct 2021 09:03:59 +0100, Mauro Carvalho Chehab wrote:
> Hi Jon,
> 
> This series is against today's next (next-20211019) and addresses missing
> links to Documentation/*.
> 
> The best would be to have the patches applied directly to the trees that
> contain the patches that moved/renamed files, and then apply the
> remaining ones either later during the merge window or just afterwards,
> whatever works best for you.
> 
> Regards,
> Mauro
> 
> Mauro Carvalho Chehab (23):
>   visorbus: fix a copyright symbol that was bad encoded
>   libbpf: update index.rst reference
>   docs: accounting: update delay-accounting.rst reference
>   MAINTAINERS: update arm,vic.yaml reference
>   MAINTAINERS: update aspeed,i2c.yaml reference
>   MAINTAINERS: update faraday,ftrtc010.yaml reference
>   MAINTAINERS: update ti,sci.yaml reference
>   MAINTAINERS: update intel,ixp46x-rng.yaml reference
>   MAINTAINERS: update nxp,imx8-jpeg.yaml reference
>   MAINTAINERS: update gemini.yaml reference
>   MAINTAINERS: update brcm,unimac-mdio.yaml reference
>   MAINTAINERS: update mtd-physmap.yaml reference

Applied patches 3-12.

>   Documentation: update vcpu-requests.rst reference
>   bpftool: update bpftool-cgroup.rst reference
>   docs: translations: zn_CN: irq-affinity.rst: add a missing extension
>   docs: translations: zh_CN: memory-hotplug.rst: fix a typo
>   docs: fs: locks.rst: update comment about mandatory file locking
>   fs: remove a comment pointing to the removed mandatory-locking file
>   Documentation/process: fix a cross reference
>   dt-bindings: mfd: update x-powers,axp152.yaml reference
>   regulator: dt-bindings: update samsung,s2mpa01.yaml reference
>   regulator: dt-bindings: update samsung,s5m8767.yaml reference
>   dt-bindings: reserved-memory: ramoops: update ramoops.yaml references

[PATCH] locks: remove changelog comments

[J. Bruce Fields]

From: "J. Bruce Fields" <bfields@redhat.com>

This is only of historical interest, and anyone interested in the
history can dig out an old version of locks.c from from git.

Triggered by the observation that it references the now-removed
Documentation/filesystems/mandatory-locking.rst.

Reported-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/locks.c | 114 ++---------------------------------------------------
 1 file changed, 4 insertions(+), 110 deletions(-)

On Tue, Oct 19, 2021 at 12:27:55PM -0400, Jeff Layton wrote:
> Yeah, I think that looks great. Send it with a changelog and I'll pull
> it into the branch I have feeding into -next.

OK!--b.

diff --git a/fs/locks.c b/fs/locks.c
index 3d6fb4ae847b..b54813eae44f 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2,117 +2,11 @@
 /*
  *  linux/fs/locks.c
  *
- *  Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
- *  Doug Evans (dje@spiff.uucp), August 07, 1992
+ * We implement four types of file locks: BSD locks, posix locks, open
+ * file description locks, and leases.  For details about BSD locks,
+ * see the flock(2) man page; for details about the other three, see
+ * fcntl(2).
  *
- *  Deadlock detection added.
- *  FIXME: one thing isn't handled yet:
- *	- mandatory locks (requires lots of changes elsewhere)
- *  Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994.
- *
- *  Miscellaneous edits, and a total rewrite of posix_lock_file() code.
- *  Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994
- *
- *  Converted file_lock_table to a linked list from an array, which eliminates
- *  the limits on how many active file locks are open.
- *  Chad Page (pageone@netcom.com), November 27, 1994
- *
- *  Removed dependency on file descriptors. dup()'ed file descriptors now
- *  get the same locks as the original file descriptors, and a close() on
- *  any file descriptor removes ALL the locks on the file for the current
- *  process. Since locks still depend on the process id, locks are inherited
- *  after an exec() but not after a fork(). This agrees with POSIX, and both
- *  BSD and SVR4 practice.
- *  Andy Walker (andy@lysaker.kvaerner.no), February 14, 1995
- *
- *  Scrapped free list which is redundant now that we allocate locks
- *  dynamically with kmalloc()/kfree().
- *  Andy Walker (andy@lysaker.kvaerner.no), February 21, 1995
- *
- *  Implemented two lock personalities - FL_FLOCK and FL_POSIX.
- *
- *  FL_POSIX locks are created with calls to fcntl() and lockf() through the
- *  fcntl() system call. They have the semantics described above.
- *
- *  FL_FLOCK locks are created with calls to flock(), through the flock()
- *  system call, which is new. Old C libraries implement flock() via fcntl()
- *  and will continue to use the old, broken implementation.
- *
- *  FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated
- *  with a file pointer (filp). As a result they can be shared by a parent
- *  process and its children after a fork(). They are removed when the last
- *  file descriptor referring to the file pointer is closed (unless explicitly
- *  unlocked).
- *
- *  FL_FLOCK locks never deadlock, an existing lock is always removed before
- *  upgrading from shared to exclusive (or vice versa). When this happens
- *  any processes blocked by the current lock are woken up and allowed to
- *  run before the new lock is applied.
- *  Andy Walker (andy@lysaker.kvaerner.no), June 09, 1995
- *
- *  Removed some race conditions in flock_lock_file(), marked other possible
- *  races. Just grep for FIXME to see them.
- *  Dmitry Gorodchanin (pgmdsg@ibi.com), February 09, 1996.
- *
- *  Addressed Dmitry's concerns. Deadlock checking no longer recursive.
- *  Lock allocation changed to GFP_ATOMIC as we can't afford to sleep
- *  once we've checked for blocking and deadlocking.
- *  Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
- *
- *  Initial implementation of mandatory locks. SunOS turned out to be
- *  a rotten model, so I implemented the "obvious" semantics.
- *  See 'Documentation/filesystems/mandatory-locking.rst' for details.
- *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
- *
- *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to
- *  check if a file has mandatory locks, used by mmap(), open() and creat() to
- *  see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
- *  Manual, Section 2.
- *  Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
- *
- *  Tidied up block list handling. Added '/proc/locks' interface.
- *  Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
- *
- *  Fixed deadlock condition for pathological code that mixes calls to
- *  flock() and fcntl().
- *  Andy Walker (andy@lysaker.kvaerner.no), April 29, 1996.
- *
- *  Allow only one type of locking scheme (FL_POSIX or FL_FLOCK) to be in use
- *  for a given file at a time. Changed the CONFIG_LOCK_MANDATORY scheme to
- *  guarantee sensible behaviour in the case where file system modules might
- *  be compiled with different options than the kernel itself.
- *  Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
- *
- *  Added a couple of missing wake_up() calls. Thanks to Thomas Meckel
- *  (Thomas.Meckel@mni.fh-giessen.de) for spotting this.
- *  Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
- *
- *  Changed FL_POSIX locks to use the block list in the same way as FL_FLOCK
- *  locks. Changed process synchronisation to avoid dereferencing locks that
- *  have already been freed.
- *  Andy Walker (andy@lysaker.kvaerner.no), Sep 21, 1996.
- *
- *  Made the block list a circular list to minimise searching in the list.
- *  Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
- *
- *  Made mandatory locking a mount option. Default is not to allow mandatory
- *  locking.
- *  Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
- *
- *  Some adaptations for NFS support.
- *  Olaf Kirch (okir@monad.swb.de), Dec 1996,
- *
- *  Fixed /proc/locks interface so that we can't overrun the buffer we are handed.
- *  Andy Walker (andy@lysaker.kvaerner.no), May 12, 1997.
- *
- *  Use slab allocator instead of kmalloc/kfree.
- *  Use generic list implementation from <linux/list.h>.
- *  Sped up posix_locks_deadlock by only considering blocked locks.
- *  Matthew Wilcox <willy@debian.org>, March, 2000.
- *
- *  Leases and LOCK_MAND
- *  Matthew Wilcox <willy@debian.org>, June, 2000.
- *  Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
  *
  * Locking conflicts and dependencies:
  * If multiple threads attempt to lock the same byte (or flock the same file)
-- 
2.31.1

Re: [PATCH] locks: remove changelog comments

[Jeff Layton]

On Tue, 2021-10-19 at 13:38 -0400, J. Bruce Fields wrote:
> From: "J. Bruce Fields" <bfields@redhat.com>
> 
> This is only of historical interest, and anyone interested in the
> history can dig out an old version of locks.c from from git.
> 
> Triggered by the observation that it references the now-removed
> Documentation/filesystems/mandatory-locking.rst.
> 
> Reported-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> ---
>  fs/locks.c | 114 ++---------------------------------------------------
>  1 file changed, 4 insertions(+), 110 deletions(-)
> 
> On Tue, Oct 19, 2021 at 12:27:55PM -0400, Jeff Layton wrote:
> > Yeah, I think that looks great. Send it with a changelog and I'll pull
> > it into the branch I have feeding into -next.
> 
> OK!--b.
> 
> diff --git a/fs/locks.c b/fs/locks.c
> index 3d6fb4ae847b..b54813eae44f 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -2,117 +2,11 @@
>  /*
>   *  linux/fs/locks.c
>   *
> - *  Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
> - *  Doug Evans (dje@spiff.uucp), August 07, 1992
> + * We implement four types of file locks: BSD locks, posix locks, open
> + * file description locks, and leases.  For details about BSD locks,
> + * see the flock(2) man page; for details about the other three, see
> + * fcntl(2).
>   *
> - *  Deadlock detection added.
> - *  FIXME: one thing isn't handled yet:
> - *	- mandatory locks (requires lots of changes elsewhere)
> - *  Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994.
> - *
> - *  Miscellaneous edits, and a total rewrite of posix_lock_file() code.
> - *  Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994
> - *
> - *  Converted file_lock_table to a linked list from an array, which eliminates
> - *  the limits on how many active file locks are open.
> - *  Chad Page (pageone@netcom.com), November 27, 1994
> - *
> - *  Removed dependency on file descriptors. dup()'ed file descriptors now
> - *  get the same locks as the original file descriptors, and a close() on
> - *  any file descriptor removes ALL the locks on the file for the current
> - *  process. Since locks still depend on the process id, locks are inherited
> - *  after an exec() but not after a fork(). This agrees with POSIX, and both
> - *  BSD and SVR4 practice.
> - *  Andy Walker (andy@lysaker.kvaerner.no), February 14, 1995
> - *
> - *  Scrapped free list which is redundant now that we allocate locks
> - *  dynamically with kmalloc()/kfree().
> - *  Andy Walker (andy@lysaker.kvaerner.no), February 21, 1995
> - *
> - *  Implemented two lock personalities - FL_FLOCK and FL_POSIX.
> - *
> - *  FL_POSIX locks are created with calls to fcntl() and lockf() through the
> - *  fcntl() system call. They have the semantics described above.
> - *
> - *  FL_FLOCK locks are created with calls to flock(), through the flock()
> - *  system call, which is new. Old C libraries implement flock() via fcntl()
> - *  and will continue to use the old, broken implementation.
> - *
> - *  FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated
> - *  with a file pointer (filp). As a result they can be shared by a parent
> - *  process and its children after a fork(). They are removed when the last
> - *  file descriptor referring to the file pointer is closed (unless explicitly
> - *  unlocked).
> - *
> - *  FL_FLOCK locks never deadlock, an existing lock is always removed before
> - *  upgrading from shared to exclusive (or vice versa). When this happens
> - *  any processes blocked by the current lock are woken up and allowed to
> - *  run before the new lock is applied.
> - *  Andy Walker (andy@lysaker.kvaerner.no), June 09, 1995
> - *
> - *  Removed some race conditions in flock_lock_file(), marked other possible
> - *  races. Just grep for FIXME to see them.
> - *  Dmitry Gorodchanin (pgmdsg@ibi.com), February 09, 1996.
> - *
> - *  Addressed Dmitry's concerns. Deadlock checking no longer recursive.
> - *  Lock allocation changed to GFP_ATOMIC as we can't afford to sleep
> - *  once we've checked for blocking and deadlocking.
> - *  Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
> - *
> - *  Initial implementation of mandatory locks. SunOS turned out to be
> - *  a rotten model, so I implemented the "obvious" semantics.
> - *  See 'Documentation/filesystems/mandatory-locking.rst' for details.
> - *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
> - *
> - *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to
> - *  check if a file has mandatory locks, used by mmap(), open() and creat() to
> - *  see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
> - *  Manual, Section 2.
> - *  Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
> - *
> - *  Tidied up block list handling. Added '/proc/locks' interface.
> - *  Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
> - *
> - *  Fixed deadlock condition for pathological code that mixes calls to
> - *  flock() and fcntl().
> - *  Andy Walker (andy@lysaker.kvaerner.no), April 29, 1996.
> - *
> - *  Allow only one type of locking scheme (FL_POSIX or FL_FLOCK) to be in use
> - *  for a given file at a time. Changed the CONFIG_LOCK_MANDATORY scheme to
> - *  guarantee sensible behaviour in the case where file system modules might
> - *  be compiled with different options than the kernel itself.
> - *  Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
> - *
> - *  Added a couple of missing wake_up() calls. Thanks to Thomas Meckel
> - *  (Thomas.Meckel@mni.fh-giessen.de) for spotting this.
> - *  Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
> - *
> - *  Changed FL_POSIX locks to use the block list in the same way as FL_FLOCK
> - *  locks. Changed process synchronisation to avoid dereferencing locks that
> - *  have already been freed.
> - *  Andy Walker (andy@lysaker.kvaerner.no), Sep 21, 1996.
> - *
> - *  Made the block list a circular list to minimise searching in the list.
> - *  Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
> - *
> - *  Made mandatory locking a mount option. Default is not to allow mandatory
> - *  locking.
> - *  Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
> - *
> - *  Some adaptations for NFS support.
> - *  Olaf Kirch (okir@monad.swb.de), Dec 1996,
> - *
> - *  Fixed /proc/locks interface so that we can't overrun the buffer we are handed.
> - *  Andy Walker (andy@lysaker.kvaerner.no), May 12, 1997.
> - *
> - *  Use slab allocator instead of kmalloc/kfree.
> - *  Use generic list implementation from <linux/list.h>.
> - *  Sped up posix_locks_deadlock by only considering blocked locks.
> - *  Matthew Wilcox <willy@debian.org>, March, 2000.
> - *
> - *  Leases and LOCK_MAND
> - *  Matthew Wilcox <willy@debian.org>, June, 2000.
> - *  Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
>   *
>   * Locking conflicts and dependencies:
>   * If multiple threads attempt to lock the same byte (or flock the same file)

Thanks, Bruce (and Mauro). Applied to the locks-next branch (and I
dropped Mauro's patch that touched the same area). It should make v5.16.

Cheers,
-- 
Jeff Layton <jlayton@kernel.org>

Re: [PATCH] locks: remove changelog comments

[Mauro Carvalho Chehab]

Em Tue, 19 Oct 2021 14:14:08 -0400
Jeff Layton <jlayton@kernel.org> escreveu:

> On Tue, 2021-10-19 at 13:38 -0400, J. Bruce Fields wrote:
> > From: "J. Bruce Fields" <bfields@redhat.com>
> > 
> > This is only of historical interest, and anyone interested in the
> > history can dig out an old version of locks.c from from git.
> > 
> > Triggered by the observation that it references the now-removed
> > Documentation/filesystems/mandatory-locking.rst.
> > 
> > Reported-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> > Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> > ---
> >  fs/locks.c | 114 ++---------------------------------------------------
> >  1 file changed, 4 insertions(+), 110 deletions(-)
> > 
> > On Tue, Oct 19, 2021 at 12:27:55PM -0400, Jeff Layton wrote:  
> > > Yeah, I think that looks great. Send it with a changelog and I'll pull
> > > it into the branch I have feeding into -next.  
> > 
> > OK!--b.
> > 
> > diff --git a/fs/locks.c b/fs/locks.c
> > index 3d6fb4ae847b..b54813eae44f 100644
> > --- a/fs/locks.c
> > +++ b/fs/locks.c
> > @@ -2,117 +2,11 @@
> >  /*
> >   *  linux/fs/locks.c
> >   *
> > - *  Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
> > - *  Doug Evans (dje@spiff.uucp), August 07, 1992
> > + * We implement four types of file locks: BSD locks, posix locks, open
> > + * file description locks, and leases.  For details about BSD locks,
> > + * see the flock(2) man page; for details about the other three, see
> > + * fcntl(2).
> >   *
> > - *  Deadlock detection added.
> > - *  FIXME: one thing isn't handled yet:
> > - *	- mandatory locks (requires lots of changes elsewhere)
> > - *  Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994.
> > - *
> > - *  Miscellaneous edits, and a total rewrite of posix_lock_file() code.
> > - *  Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994
> > - *
> > - *  Converted file_lock_table to a linked list from an array, which eliminates
> > - *  the limits on how many active file locks are open.
> > - *  Chad Page (pageone@netcom.com), November 27, 1994
> > - *
> > - *  Removed dependency on file descriptors. dup()'ed file descriptors now
> > - *  get the same locks as the original file descriptors, and a close() on
> > - *  any file descriptor removes ALL the locks on the file for the current
> > - *  process. Since locks still depend on the process id, locks are inherited
> > - *  after an exec() but not after a fork(). This agrees with POSIX, and both
> > - *  BSD and SVR4 practice.
> > - *  Andy Walker (andy@lysaker.kvaerner.no), February 14, 1995
> > - *
> > - *  Scrapped free list which is redundant now that we allocate locks
> > - *  dynamically with kmalloc()/kfree().
> > - *  Andy Walker (andy@lysaker.kvaerner.no), February 21, 1995
> > - *
> > - *  Implemented two lock personalities - FL_FLOCK and FL_POSIX.
> > - *
> > - *  FL_POSIX locks are created with calls to fcntl() and lockf() through the
> > - *  fcntl() system call. They have the semantics described above.
> > - *
> > - *  FL_FLOCK locks are created with calls to flock(), through the flock()
> > - *  system call, which is new. Old C libraries implement flock() via fcntl()
> > - *  and will continue to use the old, broken implementation.
> > - *
> > - *  FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated
> > - *  with a file pointer (filp). As a result they can be shared by a parent
> > - *  process and its children after a fork(). They are removed when the last
> > - *  file descriptor referring to the file pointer is closed (unless explicitly
> > - *  unlocked).
> > - *
> > - *  FL_FLOCK locks never deadlock, an existing lock is always removed before
> > - *  upgrading from shared to exclusive (or vice versa). When this happens
> > - *  any processes blocked by the current lock are woken up and allowed to
> > - *  run before the new lock is applied.
> > - *  Andy Walker (andy@lysaker.kvaerner.no), June 09, 1995
> > - *
> > - *  Removed some race conditions in flock_lock_file(), marked other possible
> > - *  races. Just grep for FIXME to see them.
> > - *  Dmitry Gorodchanin (pgmdsg@ibi.com), February 09, 1996.
> > - *
> > - *  Addressed Dmitry's concerns. Deadlock checking no longer recursive.
> > - *  Lock allocation changed to GFP_ATOMIC as we can't afford to sleep
> > - *  once we've checked for blocking and deadlocking.
> > - *  Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
> > - *
> > - *  Initial implementation of mandatory locks. SunOS turned out to be
> > - *  a rotten model, so I implemented the "obvious" semantics.
> > - *  See 'Documentation/filesystems/mandatory-locking.rst' for details.
> > - *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
> > - *
> > - *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to
> > - *  check if a file has mandatory locks, used by mmap(), open() and creat() to
> > - *  see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
> > - *  Manual, Section 2.
> > - *  Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
> > - *
> > - *  Tidied up block list handling. Added '/proc/locks' interface.
> > - *  Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
> > - *
> > - *  Fixed deadlock condition for pathological code that mixes calls to
> > - *  flock() and fcntl().
> > - *  Andy Walker (andy@lysaker.kvaerner.no), April 29, 1996.
> > - *
> > - *  Allow only one type of locking scheme (FL_POSIX or FL_FLOCK) to be in use
> > - *  for a given file at a time. Changed the CONFIG_LOCK_MANDATORY scheme to
> > - *  guarantee sensible behaviour in the case where file system modules might
> > - *  be compiled with different options than the kernel itself.
> > - *  Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
> > - *
> > - *  Added a couple of missing wake_up() calls. Thanks to Thomas Meckel
> > - *  (Thomas.Meckel@mni.fh-giessen.de) for spotting this.
> > - *  Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
> > - *
> > - *  Changed FL_POSIX locks to use the block list in the same way as FL_FLOCK
> > - *  locks. Changed process synchronisation to avoid dereferencing locks that
> > - *  have already been freed.
> > - *  Andy Walker (andy@lysaker.kvaerner.no), Sep 21, 1996.
> > - *
> > - *  Made the block list a circular list to minimise searching in the list.
> > - *  Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
> > - *
> > - *  Made mandatory locking a mount option. Default is not to allow mandatory
> > - *  locking.
> > - *  Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
> > - *
> > - *  Some adaptations for NFS support.
> > - *  Olaf Kirch (okir@monad.swb.de), Dec 1996,
> > - *
> > - *  Fixed /proc/locks interface so that we can't overrun the buffer we are handed.
> > - *  Andy Walker (andy@lysaker.kvaerner.no), May 12, 1997.
> > - *
> > - *  Use slab allocator instead of kmalloc/kfree.
> > - *  Use generic list implementation from <linux/list.h>.
> > - *  Sped up posix_locks_deadlock by only considering blocked locks.
> > - *  Matthew Wilcox <willy@debian.org>, March, 2000.
> > - *
> > - *  Leases and LOCK_MAND
> > - *  Matthew Wilcox <willy@debian.org>, June, 2000.
> > - *  Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
> >   *
> >   * Locking conflicts and dependencies:
> >   * If multiple threads attempt to lock the same byte (or flock the same file)  
> 
> Thanks, Bruce (and Mauro). Applied to the locks-next branch (and I
> dropped Mauro's patch that touched the same area). It should make v5.16.

Thanks! Yeah, it looks a lot cleaner without those changelog-style
comments.

> 
> Cheers,