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| author | Beau Belgrave <beaub@linux.microsoft.com> | 2023-05-20 02:07:41 +0300 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2023-05-24 04:08:33 +0300 |
| commit | ff9e1632d69e596d8ca256deb07433a8f3565038 (patch) | |
| tree | 01bbfbd82acf346b45615b32bc405331577bca7a /include/linux | |
| parent | dcbd1ac2668b5fa02069ea96d581ca3f70a7543c (diff) | |
| download | linux-ff9e1632d69e596d8ca256deb07433a8f3565038.tar.xz | |
tracing/user_events: Document user_event_mm one-shot list usage
During 6.4 development it became clear that the one-shot list used by
the user_event_mm's next field was confusing to others. It is not clear
how this list is protected or what the next field usage is for unless
you are familiar with the code.
Add comments into the user_event_mm struct indicating lock requirement
and usage. Also document how and why this approach was used via comments
in both user_event_enabler_update() and user_event_mm_get_all() and the
rules to properly use it.
Link: https://lkml.kernel.org/r/20230519230741.669-5-beaub@linux.microsoft.com
Link: https://lore.kernel.org/linux-trace-kernel/CAHk-=wicngggxVpbnrYHjRTwGE0WYscPRM+L2HO2BF8ia1EXgQ@mail.gmail.com/
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/user_events.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/user_events.h b/include/linux/user_events.h index 17d452b389de..8afa8c3a0973 100644 --- a/include/linux/user_events.h +++ b/include/linux/user_events.h @@ -20,6 +20,7 @@ struct user_event_mm { struct list_head mms_link; struct list_head enablers; struct mm_struct *mm; + /* Used for one-shot lists, protected by event_mutex */ struct user_event_mm *next; refcount_t refcnt; refcount_t tasks; |