Just a repost of patches with tags, for our consideration into v6.17.

All have tags, and the last commit is a fixup for the deadloop patch which can
be squashed into the original patch.

Joel Fernandes (6):
  smp: Document preemption and stop_machine() mutual exclusion
  rcu: Refactor expedited handling check in rcu_read_unlock_special()
  rcu: Document GP init vs hotplug-scan ordering requirements
  rcu: Document separation of rcu_state and rnp's gp_seq
  rcu: Document concurrent quiescent state reporting for offline CPUs
  [please squash] fixup! rcu: Fix rcu_read_unlock() deadloop due to IRQ
    work

 .../Data-Structures/Data-Structures.rst       |  32 +++++
 .../RCU/Design/Requirements/Requirements.rst  | 128 ++++++++++++++++++
 kernel/rcu/tree.c                             |  31 ++++-
 kernel/rcu/tree.h                             |  10 +-
 kernel/rcu/tree_plugin.h                      |  90 ++++++++++--
 kernel/smp.c                                  |  26 ++--
 6 files changed, 293 insertions(+), 24 deletions(-)

-- 
2.34.1

[+CC Frederic]

Hi Joel and Neeraj,

Belated drive-by review.  Please see below.

On Tue, 15 Jul 2025 16:01:50 -0400, Joel Fernandes wrote:
> Just a repost of patches with tags, for our consideration into v6.17.
> 
> All have tags, and the last commit is a fixup for the deadloop patch which can
> be squashed into the original patch.
> 
> Joel Fernandes (6):
>   smp: Document preemption and stop_machine() mutual exclusion
>   rcu: Refactor expedited handling check in rcu_read_unlock_special()
>   rcu: Document GP init vs hotplug-scan ordering requirements
>   rcu: Document separation of rcu_state and rnp's gp_seq
>   rcu: Document concurrent quiescent state reporting for offline CPUs
>   [please squash] fixup! rcu: Fix rcu_read_unlock() deadloop due to IRQ
>     work

There seems to be a couple of issues in the S-O-B chains of commits listed
below (in rcu/next):

 * dcf1668449c9 ("rcu: Document GP init vs hotplug-scan ordering requirements")
 * bb1c373934db ("rcu: Document concurrent quiescent state reporting for offline CPUs")

They have a "Co-developed-by:" tag without a corresponding "Signed-off-by:"
tag [1].

Or, if the contribution is too minor to have a "Signed-off-by:",
then a "Suggested-by:" tag with a "Link:" to the relevant message should
suffice.

I have no idea which approach suits better in each commit above.

[1]: Documentation/process/submitting-patches.rst
     section "When to use Acked-by:, Cc:, and Co-developed-by:"

Quoting relevant paragraph:

  Co-developed-by: states that the patch was co-created by multiple developers;
  it is used to give attribution to co-authors (in addition to the author
  attributed by the From: tag) when several people work on a single patch.  Since
  Co-developed-by: denotes authorship, every Co-developed-by: must be immediately
  followed by a Signed-off-by: of the associated co-author.  Standard sign-off
  procedure applies, i.e. the ordering of Signed-off-by: tags should reflect the
  chronological history of the patch insofar as possible, regardless of whether
  the author is attributed via From: or Co-developed-by:.  Notably, the last
  Signed-off-by: must always be that of the developer submitting the patch.

Side note:
  scripts/checkpatch.pl would have complained about those missing
  Signed-off-by: tags.

> 
>  .../Data-Structures/Data-Structures.rst       |  32 +++++
>  .../RCU/Design/Requirements/Requirements.rst  | 128 ++++++++++++++++++

I'm seeing sub-optimal uses of reST markups in Requirements.rst from kernel
documentation stand point.

I'm going to submit a patch or two to improve them, but I can't promise when.
They will likely be only cosmetic cleanups and I'm OK with it upstreamed as
it is.

        Thanks, Akira

>  kernel/rcu/tree.c                             |  31 ++++-
>  kernel/rcu/tree.h                             |  10 +-
>  kernel/rcu/tree_plugin.h                      |  90 ++++++++++--
>  kernel/smp.c                                  |  26 ++--
>  6 files changed, 293 insertions(+), 24 deletions(-)
> 
> -- 
> 2.34.1

Hi,

On Sun, Jul 20, 2025 at 10:01 AM Akira Yokosawa <akiyks@gmail.com> wrote:

...

> There seems to be a couple of issues in the S-O-B chains of commits listed
> below (in rcu/next):
>
>  * dcf1668449c9 ("rcu: Document GP init vs hotplug-scan ordering requirements")
>  * bb1c373934db ("rcu: Document concurrent quiescent state reporting for offline CPUs")
>
> They have a "Co-developed-by:" tag without a corresponding "Signed-off-by:"
> tag [1].
>
> Or, if the contribution is too minor to have a "Signed-off-by:",
> then a "Suggested-by:" tag with a "Link:" to the relevant message should
> suffice.
>
> I have no idea which approach suits better in each commit above.
>
> [1]: Documentation/process/submitting-patches.rst
>      section "When to use Acked-by:, Cc:, and Co-developed-by:"
>

Thanks for reviewing this! I will fix the tags.


> Quoting relevant paragraph:
>
>   Co-developed-by: states that the patch was co-created by multiple developers;
>   it is used to give attribution to co-authors (in addition to the author
>   attributed by the From: tag) when several people work on a single patch.  Since
>   Co-developed-by: denotes authorship, every Co-developed-by: must be immediately
>   followed by a Signed-off-by: of the associated co-author.  Standard sign-off
>   procedure applies, i.e. the ordering of Signed-off-by: tags should reflect the
>   chronological history of the patch insofar as possible, regardless of whether
>   the author is attributed via From: or Co-developed-by:.  Notably, the last
>   Signed-off-by: must always be that of the developer submitting the patch.
>
> Side note:
>   scripts/checkpatch.pl would have complained about those missing
>   Signed-off-by: tags.
>
> >
> >  .../Data-Structures/Data-Structures.rst       |  32 +++++
> >  .../RCU/Design/Requirements/Requirements.rst  | 128 ++++++++++++++++++
>
> I'm seeing sub-optimal uses of reST markups in Requirements.rst from kernel
> documentation stand point.
>
> I'm going to submit a patch or two to improve them, but I can't promise when.
> They will likely be only cosmetic cleanups and I'm OK with it upstreamed as
> it is.
>

Thanks!


- Neeraj

> On Jul 21, 2025, at 12:29 AM, Neeraj upadhyay <neeraj.iitr10@gmail.com> wrote:
> 
> Hi,
> 
> On Sun, Jul 20, 2025 at 10:01 AM Akira Yokosawa <akiyks@gmail.com> wrote:
> 
> ...
> 
>> There seems to be a couple of issues in the S-O-B chains of commits listed
>> below (in rcu/next):
>> 
>> * dcf1668449c9 ("rcu: Document GP init vs hotplug-scan ordering requirements")
>> * bb1c373934db ("rcu: Document concurrent quiescent state reporting for offline CPUs")
>> 
>> They have a "Co-developed-by:" tag without a corresponding "Signed-off-by:"
>> tag [1].
>> 
>> Or, if the contribution is too minor to have a "Signed-off-by:",
>> then a "Suggested-by:" tag with a "Link:" to the relevant message should
>> suffice.
>> 
>> I have no idea which approach suits better in each commit above.
>> 
>> [1]: Documentation/process/submitting-patches.rst
>>     section "When to use Acked-by:, Cc:, and Co-developed-by:"
>> 
> 
> Thanks for reviewing this! I will fix the tags.
> 
> 
>> Quoting relevant paragraph:
>> 
>>  Co-developed-by: states that the patch was co-created by multiple developers;
>>  it is used to give attribution to co-authors (in addition to the author
>>  attributed by the From: tag) when several people work on a single patch.  Since
>>  Co-developed-by: denotes authorship, every Co-developed-by: must be immediately
>>  followed by a Signed-off-by: of the associated co-author.  Standard sign-off
>>  procedure applies, i.e. the ordering of Signed-off-by: tags should reflect the
>>  chronological history of the patch insofar as possible, regardless of whether
>>  the author is attributed via From: or Co-developed-by:.  Notably, the last
>>  Signed-off-by: must always be that of the developer submitting the patch.
>> 
>> Side note:
>>  scripts/checkpatch.pl would have complained about those missing
>>  Signed-off-by: tags.
>> 
>>> 
>>> .../Data-Structures/Data-Structures.rst       |  32 +++++
>>> .../RCU/Design/Requirements/Requirements.rst  | 128 ++++++++++++++++++
>> 
>> I'm seeing sub-optimal uses of reST markups in Requirements.rst from kernel
>> documentation stand point.
>> 
>> I'm going to submit a patch or two to improve them, but I can't promise when.
>> They will likely be only cosmetic cleanups and I'm OK with it upstreamed as
>> it is.
>> 
> 
> Thanks!

Thanks, I appreciate that!

- Joel

> 
> 
> - Neeraj

Hi Joel,

On Wed, Jul 16, 2025 at 1:32 AM Joel Fernandes <joelagnelf@nvidia.com> wrote:
>
> Just a repost of patches with tags, for our consideration into v6.17.
>
> All have tags, and the last commit is a fixup for the deadloop patch which can
> be squashed into the original patch.
>
> Joel Fernandes (6):
>   smp: Document preemption and stop_machine() mutual exclusion
>   rcu: Refactor expedited handling check in rcu_read_unlock_special()
>   rcu: Document GP init vs hotplug-scan ordering requirements
>   rcu: Document separation of rcu_state and rnp's gp_seq
>   rcu: Document concurrent quiescent state reporting for offline CPUs
>   [please squash] fixup! rcu: Fix rcu_read_unlock() deadloop due to IRQ
>     work
>

I have included patches 2-6 here:
https://git.kernel.org/pub/scm/linux/kernel/git/neeraj.upadhyay/linux-rcu.git/log/?h=rcu.merge.16.07.2025c
for testing

Fixed few whitespaces errors in the documentation.

I see below warnings while doing `make htmldocs`. Can you suggest a
fix for these?

Documentation/RCU/Design/Data-Structures/Data-Structures.rst:305:
ERROR: Unexpected indentation.
Documentation/RCU/Design/Data-Structures/Data-Structures.rst:307:
WARNING: Block quote ends without a blank line; unexpected unindent.


- Neeraj