On June 21, 2024 9:27:34 PM PDT, Michael Ellerman [off-list ref] wrote:

Konstantin Ryabitsev [off-list ref] writes:

quoted

Based on multiple conversations, most recently on the ksummit mailing
list [1], add some best practices for using the Link trailer, such as:

- how to use markdown-like bracketed numbers in the commit message to
indicate the corresponding link
- when to use lore.kernel.org vs patch.msgid.link domains

Cc: ksummit@lists.linux.dev
Link: https://lore.kernel.org/20240617-arboreal-industrious-hedgehog-5b84ae@meerkat # [1]
Signed-off-by: Konstantin Ryabitsev <redacted>
---
 Documentation/process/maintainer-tip.rst | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/Documentation/process/maintainer-tip.rst b/Documentation/process/maintainer-tip.rst
index 64739968afa6..ba312345d030 100644
--- a/Documentation/process/maintainer-tip.rst
+++ b/Documentation/process/maintainer-tip.rst

@@ -372,17 +372,31 @@ following tag ordering scheme:
 
  - Link: ``https://link/to/information``
 
-   For referring to an email on LKML or other kernel mailing lists,
-   please use the lore.kernel.org redirector URL::
+   For referring to an email posted to the kernel mailing lists, please
+   use the lore.kernel.org redirector URL::
 
-     https://lore.kernel.org/r/email-message@id
+     Link: https://lore.kernel.org/email-message-id@here
 
-   The kernel.org redirector is considered a stable URL, unlike other email
-   archives.
+   This URL should be used when referring to relevant mailing list
+   topics, related patch sets, or other notable discussion threads.
+   A convenient way to associate ``Link:`` trailers with the commit
+   message is to use markdown-like bracketed notation, for example::
 
-   Maintainers will add a Link tag referencing the email of the patch
-   submission when they apply a patch to the tip tree. This tag is useful
-   for later reference and is also used for commit notifications.
+     A similar approach was attempted before as part of a different
+     effort [1], but the initial implementation caused too many
+     regressions [2], so it was backed out and reimplemented.
+
+     Link: https://lore.kernel.org/some-msgid@here # [1]
+     Link: https://bugzilla.example.org/bug/12345  # [2]

Does it actually make sense to use the Link: prefix here? These sort of
links are part of the prose, they're not something a script can download
and make any sense of.

I see some existing usage of the above style, but equally there's lots
of examples of footnote-style links without the Link: tag, eg:

I moved from that to using Link: because checkpatch would complain about my long (URL) lines unless it had a Link tag :P

commit 40b561e501768ef24673d0e1d731a7b9b1bc6709
Merge: d9f843fbd45e 31611cc8faa0
Author: Arnd Bergmann [off-list ref]
Date:   Mon Apr 29 22:29:44 2024 +0200

   Merge tag 'tee-ts-for-v6.10' of https://git.linaro.org/people/jens.wiklander/linux-tee into soc/drivers

   TEE driver for Trusted Services

   This introduces a TEE driver for Trusted Services [1].

   Trusted Services is a TrustedFirmware.org project that provides a
   framework for developing and deploying device Root of Trust services in
   FF-A [2] Secure Partitions. The project hosts the reference
   implementation of Arm Platform Security Architecture [3] for Arm
   A-profile devices.

   ...

   [1] https://www.trustedfirmware.org/projects/trusted-services/
   [2] https://developer.arm.com/documentation/den0077/
   [3] https://www.arm.com/architecture/security-features/platform-security


The above style is standard markdown style for reference links (or as
standard as markdown gets).

It's a good point. If we're formalizing this, why not literally use markdown instead? (I guess the answer is that out-of-line links/footnotes isn't standardized.)

Playing devil's advocate, outside of the kernel, these are the two most common styles I've seen:

Foo[1]
...
[1]: https://....

and

Bar[^1]
...
[^1] https://...

Personally, I only want to have a single official way to do this, and don't care much what it is. I have a minor preference for what you've described:

Baz[1]
...
[1] https://...

-Kees

-- 
Kees Cook