doc.2024.06.06a: Documentation updates.
fixes.2024.07.04a: Miscellaneous fixes.
mb.2024.06.28a: Grace-period memory-barrier redundancy removal.
nocb.2024.06.03a: No-CB CPU updates.
rcu-tasks.2024.06.06a: RCU-Tasks updates.
rcutorture.2024.06.06a: Torture-test updates.
srcu.2024.06.18a: SRCU polled-grace-period updates.

When the grace period kthread checks the extended quiescent state
counter of a CPU, full ordering is necessary to ensure that either:

* If the GP kthread observes the remote target in an extended quiescent
  state, then that target must observe all accesses prior to the current
  grace period, including the current grace period sequence number, once
  it exits that extended quiescent state.

or:

* If the GP kthread observes the remote target NOT in an extended
  quiescent state, then the target further entering in an extended
  quiescent state must observe all accesses prior to the current
  grace period, including the current grace period sequence number, once
  it enters that extended quiescent state.

This ordering is enforced through a full memory barrier placed right
before taking the first EQS snapshot. However this is superfluous
because the snapshot is taken while holding the target's rnp lock which
provides the necessary ordering through its chain of
smp_mb__after_unlock_lock().

Remove the needless explicit barrier before the snapshot and put a
comment about the implicit barrier newly relied upon here.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

This commit expands on the ordering properties of rcu_assign_pointer()
and rcu_dereference(), outlining their constraints on CPUs and compilers.

Reported-by: Rao Shoaib <rao.shoaib@oracle.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

This commit adds more detail to the Tasks RCU and Tasks Rude RCU
descriptions in Requirements.rst.  While in the area, add Tasks Trace
RCU to the Tasks-RCU table of contents.

Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>

arrayRCU.rst has been removed since commit ef2555cf68c3 ("doc: Remove
arrayRCU.rst") but is still referenced by whatisRCU.rst. Update it to
reflect the current state of the documentation.

Signed-off-by: Zenghui Yu <zenghui.yu@linux.dev>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

Pull documentation updates from Jonathan Corbet:
 "A moderatly busy cycle for development this time around.

   - Some cleanup of the main index page for easier navigation

   - Rework some of the other top-level pages for better readability
     and, with luck, fewer merge conflicts in the future.

   - Submit-checklist improvements, hopefully the first of many.

   - New Italian translations

   - A fair number of kernel-doc fixes and improvements. We have also
     dropped the recommendation to use an old version of Sphinx.

   - A new document from Thorsten on bisection

  ... and lots of fixes and updates"

* tag 'docs-6.9' of git://git.lwn.net/linux: (54 commits)
  docs: verify/bisect: fixes, finetuning, and support for Arch
  docs: Makefile: Add dependency to $(YNL_INDEX) for targets other than htmldocs
  docs: Move ja_JP/howto.rst to ja_JP/process/howto.rst
  docs: submit-checklist: use subheadings
  docs: submit-checklist: structure by category
  docs: new text on bisecting which also covers bug validation
  docs: drop the version constraints for sphinx and dependencies
  docs: kerneldoc-preamble.sty: Remove code for Sphinx <2.4
  docs: Restore "smart quotes" for quotes
  docs/zh_CN: accurate translation of "function"
  docs: Include simplified link titles in main index
  docs: Correct formatting of title in admin-guide/index.rst
  docs: kernel_feat.py: fix build error for missing files
  MAINTAINERS: Set the field name for subsystem profile section
  kasan: Add documentation for CONFIG_KASAN_EXTRA_INFO
  Fixed case issue with 'fault-injection' in documentation
  kernel-doc: handle #if in enums as well
  Documentation: update mailing list addresses
  doc: kerneldoc.py: fix indentation
  scripts/kernel-doc: simplify signature printing
  ...

This commit completes the list of call_rcu*() functions that are not
guaranteed to have their callbacks executing on the same CPU.  While in
the area, fix an unrelated typo.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>

This commit explicitly states that you should initialize any locks to
be used by readers in your SLAB_TYPESAFE_BY_RCU constructor.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>

This commit adds CONFIG_RCU_STRICT_GRACE_PERIOD to the list of debugging
Kconfig options in checklist.rst.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>

In kernels built with CONFIG_PREEMPT_RT=n, spinlock critical sections
are RCU readers because they disable preemption.  However, they are also
RCU readers in CONFIG_PREEMPT_RT=y because in that case the locking
primitives contain rcu_read_lock() and rcu_read_unlock().  Therefore,
upgrade checklist.rst to document this non-obvious case.

While in the area, fix a typo by changing "read-side critical" to
"read-side critical section".

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>