[PATCH] CLKDEV: return from clk_find as soon as we get maching clk

[PATCH] CLKDEV: return from clk_find as soon as we get maching clk

[Viresh KUMAR]

clk_find function looks for clock with matching dev_id and con_id.
We should return from clk_find as soon as we get a clock with matching dev_id
and con_id. This can be done by comparing variable "match" with 3.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
---
 arch/arm/common/clkdev.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/arm/common/clkdev.c b/arch/arm/common/clkdev.c
index aae5bc0..736dfba 100644
--- a/arch/arm/common/clkdev.c
+++ b/arch/arm/common/clkdev.c
@@ -55,6 +55,9 @@ static struct clk *clk_find(const char *dev_id, const char *con_id)
 		if (match == 0)
 			continue;
 
+		if (match == 3)
+			return p->clk;
+
 		if (match > best) {
 			clk = p->clk;
 			best = match;
-- 
1.6.0.2

[PATCH] CLKDEV: return from clk_find as soon as we get maching clk

[Russell King - ARM Linux]

On Tue, Mar 02, 2010 at 04:35:54PM +0530, Viresh KUMAR wrote:
> clk_find function looks for clock with matching dev_id and con_id.
> We should return from clk_find as soon as we get a clock with matching dev_id
> and con_id. This can be done by comparing variable "match" with 3.

This breaks the semantics function.  Please look again at the code you're
modifying, and ascertain whether you're changing the semantics of it,
particularly with respect to what happens _in addition_ to returning the
struct clk.

Hint: "return p->clk" is insufficient.

[PATCH] CLKDEV: return from clk_find as soon as we get maching clk

[Uwe Kleine-König]

Hello,

On Tue, Mar 02, 2010 at 08:39:11PM +0000, Russell King - ARM Linux wrote:
> On Tue, Mar 02, 2010 at 04:35:54PM +0530, Viresh KUMAR wrote:
> > clk_find function looks for clock with matching dev_id and con_id.
> > We should return from clk_find as soon as we get a clock with matching dev_id
> > and con_id. This can be done by comparing variable "match" with 3.
> 
> This breaks the semantics function.  Please look again at the code you're
> modifying, and ascertain whether you're changing the semantics of it,
> particularly with respect to what happens _in addition_ to returning the
> struct clk.
> 
> Hint: "return p->clk" is insufficient.
I starred a the code a bit, but I don't see the problem here.  match is
always <= 3 so if it is 3 in one iteration best increases to 3 and clk
isn't touched anymore.  The other statements in the loop have no side
effects either.

Apart from that a while back I thought about removing

	if (match == 0)
		continue;

as if match is 0 the next if condition is false.  I don't remember why I
didn't do it.  Maybe I checked the generated code and it made no
difference.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

[PATCH] CLKDEV: return from clk_find as soon as we get maching clk

[Russell King - ARM Linux]

On Tue, Mar 02, 2010 at 10:01:38PM +0100, Uwe Kleine-K?nig wrote:
> I starred a the code a bit, but I don't see the problem here.  match is
> always <= 3 so if it is 3 in one iteration best increases to 3 and clk
> isn't touched anymore.  The other statements in the loop have no side
> effects either.

Yes, you're right - I thought there was some additional code at the end
of the function - was thinking of a previous revision of the code.

I'd still prefer the conditional code to be a 'clk = p->clk; break;'
though, to keep the flow of the code the same.