Merge tag 'trace-ringbuffer-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-traceHEADmaster

Pull ring-buffer updates from Steven Rostedt:

 - Remove unneeded semicolon

   A macro ended with a semicolon that wasn't needed.

 - Fix freeing cpu_buffer extra subbuffer with order greater than zero

   When the cpu_buffer was being freed, its "free" page, was using
   free_page() to free it when it could be more than one page.

 - Hold the cpu_buffer lock when resizing the subbuffer

   The freeing of the "free" page of the cpu_buffer was done without
   locking. The order of the data was being saved and then the "free"
   page was set to NULL. But there is a race that the "free" page could
   have been updated between those two operations. Add locking around it
   to prevent the race.

 - Save the order of the data along with the data in the free page

   The cpu_buffer would store just the data portion of the subbuffer
   page in its descriptor. But it did not store the order of the data
   pages. The order was being saved in the global buffer descriptor. But
   this leads to races.

   Have the cpu_buffer save the subbuf data along with its metadata
   (which includes the order of the page) to make sure when it frees it,
   it frees the correct order along with it.

 - Remove the subbuf_size and use the order directly when needed

   Having a size field for the size of the subbufer along with its order
   allowed for races to have them get out of sync. Remove the
   subbuf_size and use the order from the subbuf meta data directly
   under locks.

   Use the subbuf_order for other calculations in the ring buffer.

 - Remove the useless "cpus" field of trace_buffer

   The code has been restructured and the "cpus" field is no longer
   used. Remove it.

 - Remove the "mapped" field of the ring buffer and use a helper
   function instead.

   The "mapped" field has become a bit overused and made the code come
   complex in using a counter for what is denoted as being mapped or
   not. There are other fields that are set when the ring buffer is
   considered mapped. Add a helper function to check those fields and
   use that instead of keeping track of a counter.

* tag 'trace-ringbuffer-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Remove ring_buffer_per_cpu::mapped
  ring-buffer: Remove trace_buffer::cpus
  ring-buffer: Dynamically calculate max_data_size
  ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page()
  ring-buffer: Fix subbuf resize race with ring buffer readers
  ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page
  ring-buffer: Hold cpu_buffer::lock when resizing a subbuf
  ring-buffer: Free cpu_buffer::free_page with subbuf_order
  ring-buffer: drop unneeded semicolon

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