linux-kernel - Re: [PATCH 06/12] genericirq: make irq

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Message-ID: <Pine.LNX.4.64.1003211153470.7805@ask.diku.dk>
Date:	Sun, 21 Mar 2010 12:03:45 +0100 (CET)
From:	Julia Lawall <julia@...u.dk>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Yinghai Lu <yinghai@...nel.org>, Ingo Molnar <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Suresh Siddha <suresh.b.siddha@...el.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 06/12] genericirq: make irq_chip related function to take
 desc

I also worked on this, but only sent it to Thomas and Yinghai.  Onthe 
other hand, I mostly like your solution better, because it has the 
unintended side-effect of getting rid of some blank spaces after {s.

My rule was also more complicated in that it also searches for conditions 
in which it is not sure to be doing the right thing.  I will send those in 
another message.

> @ DECL @
> struct irq_chip CHIP;
> identifier METHOD;
> identifier METHOD_NAME;
> @@
>  CHIP.METHOD_NAME = METHOD;
> 
> @ @
> identifier DECL.METHOD;
> identifier IRQ;
> @@
>  METHOD(
> -		unsigned int IRQ
> +		struct irq_desc *unused
>  , ...) {
>  }

I didn't think of making a special rule for this.  It could consider any 
case where the body is ... when != IRQ

> @ @
> identifier DECL.METHOD;
> identifier IRQ;
> identifier DESC;
> @@
>  METHOD(
> -		unsigned int IRQ
> +		struct irq_desc *DESC
>  , ...) {
> +	unsigned int IRQ = DESC->irq;
>  	...
> -	struct irq_desc *DESC = irq_to_desc(IRQ);
> 	...
>  }
> 
> @ @
> identifier DECL.METHOD;
> identifier IRQ;
> identifier DESC;
> @@
>  METHOD(
> -		unsigned int IRQ
> +		struct irq_desc *DESC
>  , ...) {
> +	unsigned int IRQ = DESC->irq;
>  	...
> -	struct irq_desc *DESC;
> 	...
> -	DESC = irq_to_desc(IRQ);
> 	...
>  }
> 
> @ @
> identifier DECL.METHOD;
> identifier IRQ;
> @@
>  METHOD(
> -		unsigned int IRQ
> +		struct irq_desc *desc
>  , ...) {
> +	unsigned int IRQ = desc->irq;
>  ...
>  }
> 
> @ @
> identifier DECL.METHOD;
> identifier FUNC;
> identifier IRQ;
> @@
>  FUNC(...) {
>  <...
> 	METHOD(
> -		IRQ
> +		irq_to_desc(IRQ)
>  		, ... )
>  ...>
>  }

I don't think FUNC(...) { <... and ...> } are needed here.  The goal is to 
make the change everywhere the call appears.

> @ @
> identifier FUNC;
> identifier DESC;
> identifier IRQ;
> @@
>  FUNC(..., struct irq_desc *DESC, ...) {
>  ...
>  	unsigned int IRQ = DESC->irq;
>  <...
> -	irq_to_desc(IRQ)
> +	DESC
>  ...>
>  }

This rule can be extended as follows:

@ @
identifier FUNC;
identifier DESC;
identifier IRQ;
identifier FLD;
@@
 FUNC(..., struct irq_desc *DESC, ...) {
 ...
        unsigned int IRQ = DESC->irq;
 <...
(
-       irq_to_desc(IRQ)
+       DESC
|
-       irq_desc[IRQ].FLD
+       DESC->FLD
)
 ...>
 }

Doing so gets rid of more references to IRQ.

Another case that can be treated is method calls via a pointer:

@@
expression arg;
struct irq_desc *desc;
struct irq_chip *ic;
identifier fun;
@@

(
  desc->chip->fun(
-   arg
+   desc
    ,...)
|
  ic->fun(
-   arg
+   irq_to_desc(arg)
    ,...)
)

julia

> @ @
> identifier FUNC;
> identifier DESC;
> identifier IRQ;
> @@
>  FUNC(..., struct irq_desc *DESC, ...) {
>  ...
> -	unsigned int IRQ = DESC->irq;
>  ... when != IRQ
>  }
--
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