On Wed, Feb 25, 2015 at 10:53:30PM +0800, Shawn Guo wrote:

On the first day back from Chinese new year holiday, I got a regression
report from rmk, saying Ethernet stops working on HimmingBoard with
v4.0-rc1.

I read through the thread [1] and found a couple of i.MX audio drivers
are also affected per Stephen's Coccinelle report.  That's why I came up
with this series based on Quentin's structclk.cocci, Stephen's result
and Mike's input (thanks all).

Not all places need to be fixed in this way.

There are two broad cases:

1. Where we are trying to determine if two clocks obtained from clk_get()
   are the same clock.  IOW:

	probe()
	{
		clk1 = clk_get(dev, ...);
		clk2 = clk_get(dev, ...);

		if (clk1 == clk2)
			do_something();
	}

2. Where we are trying to determine if a clock selected from a set of
   previously obtained clk_get()'d clocks is the same as a one of those
   clocks.  IOW:

	probe()
	{
		clk1 = clk_get(dev, ...);
		clk2 = clk_get(dev, ...);
	}
...
	some_fn()
	{
		clk = select_best_clock(clk1, clk2);
		if (clk == previously_selected_clk) {
			previously_selected_clk = clk;
			do_something();
		}
	}

Case 1 applies in places like the Kirkwood I2S driver, and the iMX6
ethernet code, and it's these cases which need to be fixed.

Case 2 applies in the Armada DRM driver, and these cases need not be
"fixed".

To put it a different way: case 1 is when you're testing to see whether
two clocks refer to the same clock.  case 2 is when you're testing
whether the cached clk cookie is the same.

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