ring-buffer: Place duplicate expression into a single function

While discussing the strictness of the 80 character limit on the
Kernel Summit Discussion mailing list, I showed examples that I
broke that limit slightly with some algorithms. In discussing with
John Linville, what looked better, I realized that two of the
80 char breaking culprits were an identical expression.

As a clean up, this patch moves the identical expression into its
own helper function and that is used instead. As a side effect,
the offending code is now under the 80 character limit. :-)

This clean up code also changes the expression from

	(A - B) - C  to  A - (B + C)

This makes the code look a little nicer too.

Cc: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2010-09-01 12:23:12 -04:00 коммит произвёл Steven Rostedt
Родитель c9cf4a019c
Коммит f6195aa09e
1 изменённых файлов: 15 добавлений и 6 удалений

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@ -2606,6 +2606,19 @@ void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu)
}
EXPORT_SYMBOL_GPL(ring_buffer_record_enable_cpu);
/*
* The total entries in the ring buffer is the running counter
* of entries entered into the ring buffer, minus the sum of
* the entries read from the ring buffer and the number of
* entries that were overwritten.
*/
static inline unsigned long
rb_num_of_entries(struct ring_buffer_per_cpu *cpu_buffer)
{
return local_read(&cpu_buffer->entries) -
(local_read(&cpu_buffer->overrun) + cpu_buffer->read);
}
/**
* ring_buffer_entries_cpu - get the number of entries in a cpu buffer
* @buffer: The ring buffer
@ -2614,16 +2627,13 @@ EXPORT_SYMBOL_GPL(ring_buffer_record_enable_cpu);
unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu)
{
struct ring_buffer_per_cpu *cpu_buffer;
unsigned long ret;
if (!cpumask_test_cpu(cpu, buffer->cpumask))
return 0;
cpu_buffer = buffer->buffers[cpu];
ret = (local_read(&cpu_buffer->entries) - local_read(&cpu_buffer->overrun))
- cpu_buffer->read;
return ret;
return rb_num_of_entries(cpu_buffer);
}
EXPORT_SYMBOL_GPL(ring_buffer_entries_cpu);
@ -2684,8 +2694,7 @@ unsigned long ring_buffer_entries(struct ring_buffer *buffer)
/* if you care about this being correct, lock the buffer */
for_each_buffer_cpu(buffer, cpu) {
cpu_buffer = buffer->buffers[cpu];
entries += (local_read(&cpu_buffer->entries) -
local_read(&cpu_buffer->overrun)) - cpu_buffer->read;
entries += rb_num_of_entries(cpu_buffer);
}
return entries;