From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Fri, 22 Nov 2024 21:11:17 +0000 (-0800)
Subject: Merge tag 'trace-ring-buffer-v6.13' of git://git.kernel.org/pub/scm/linux/kernel... 
X-Git-Tag: microblaze-v6.16~581
X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=f1db825805d48cee6826b7dc082a04112c1f0c8d;p=linux-2.6-microblaze.git

Merge tag 'trace-ring-buffer-v6.13' of git://git./linux/kernel/git/trace/linux-trace

Pull trace ring-buffer updates from Steven Rostedt:

 - Limit time interrupts are disabled in rb_check_pages()

   rb_check_pages() is called after the ring buffer size is updated to
   make sure that the ring buffer has not been corrupted. Commit
   c2274b908db0 ("ring-buffer: Fix a race between readers and resize
   checks") fixed a race with the check pages and simultaneous resizes
   to the ring buffer by adding a raw_spin_lock_irqsave() around the
   check operation. Although this was a simple fix, it would hold
   interrupts disabled for non determinative amount of time. This could
   harm PREEMPT_RT operations.

   Instead, modify the logic by adding a counter when the buffer is
   modified and to release the raw_spin_lock() at each iteration. It
   checks the counter under the lock to see if a modification happened
   during the loop, and if it did, it would restart the loop up to 3
   times. After 3 times, it will simply exit the check, as it is
   unlikely that would ever happen as buffer resizes are rare
   occurrences.

 - Replace some open coded str_low_high() with the helper

 - Fix some documentation/comments

* tag 'trace-ring-buffer-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Correct a grammatical error in a comment
  ring-buffer: Use str_low_high() helper in ring_buffer_producer()
  ring-buffer: Reorganize kerneldoc parameter names
  ring-buffer: Limit time with disabled interrupts in rb_check_pages()
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f1db825805d48cee6826b7dc082a04112c1f0c8d