Re: [PATCH 5/5] drivers/video/msm/mdp.c: adjust error handling code

On Mon, Jul 04, 2011 at 04:11:45PM +0200, Julia Lawall wrote:

From: Julia Lawall <redacted>

Use the error handling code at the end of the function, rather than
returning directly.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
identifier x;
@@

kfree(x)

@@
identifier r.x;
expression E1!=0,E2,E3,E4;
statement S;
@@

(
if (<+...x...+>) S
|
if (...) { ... when != kfree(x)
               when != if (...) { ... kfree(x); ... }
               when != x = E3
* return E1;
}
... when != x = E2
if (...) { ... when != x = E4
 kfree(x); ... return ...; }
)
// </smpl>

Signed-off-by: Julia Lawall <redacted>

Applied, thanks.

I wonder if the error handling code at the end of the function should be
calling clk_put as well?  In that case, having a separate label for this
case would be useful.  Otherwise, one of error_request_irq and error_get_clk
can be deleted

The MSM implementation for it is simply a nop, so it's not going to
really matter one way or the other. In terms of general consistency it
might be worth implementing.

I expect that there are probably quite a few drivers that don't balance
out their clk_get()'s with clk_put()'s however, perhaps this is another
semantic patch candidate? At the very least it would be interesting to
see the statistics.