[PATCH] rcu: Make struct rcu_head searchable

[PATCH] rcu: Make struct rcu_head searchable

[Steven Rostedt]

After wasting too much time trying to see where struct rcu_head was
declared, I finally found it in include/linux/types.h as a define for
callback_head!

To prevent other developers from wasting their precious time in
searching for this structure, add a comment to help them find it!

Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven "frustrated" Rostedt <rostedt@goodmis.org>

diff --git a/include/linux/types.h b/include/linux/types.h
index 4d118ba..073e9a8 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -210,6 +210,9 @@ struct callback_head {
 	struct callback_head *next;
 	void (*func)(struct callback_head *head);
 };
+/*
+ * Make "struct rcu_head {" seachable with this comment.
+ */
 #define rcu_head callback_head
 
 #endif /*  __ASSEMBLY__ */

Re: [PATCH] rcu: Make struct rcu_head searchable

[Paul E. McKenney]

On Wed, Nov 13, 2013 at 12:02:25PM -0500, Steven Rostedt wrote:
> After wasting too much time trying to see where struct rcu_head was
> declared, I finally found it in include/linux/types.h as a define for
> callback_head!
> 
> To prevent other developers from wasting their precious time in
> searching for this structure, add a comment to help them find it!
> 
> Cc: Al Viro <viro@ZenIV.linux.org.uk>
> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> Signed-off-by: Steven "frustrated" Rostedt <rostedt@goodmis.org>

The cscope tool is your friend in this case, but nevertheless:

Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

> diff --git a/include/linux/types.h b/include/linux/types.h
> index 4d118ba..073e9a8 100644
> --- a/include/linux/types.h
> +++ b/include/linux/types.h
> @@ -210,6 +210,9 @@ struct callback_head {
>  	struct callback_head *next;
>  	void (*func)(struct callback_head *head);
>  };
> +/*
> + * Make "struct rcu_head {" seachable with this comment.
> + */
>  #define rcu_head callback_head
> 
>  #endif /*  __ASSEMBLY__ */
> 

Re: [PATCH] rcu: Make struct rcu_head searchable

[Steven Rostedt]

On Wed, 13 Nov 2013 09:12:05 -0800
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:

> On Wed, Nov 13, 2013 at 12:02:25PM -0500, Steven Rostedt wrote:
> > After wasting too much time trying to see where struct rcu_head was
> > declared, I finally found it in include/linux/types.h as a define for
> > callback_head!
> > 
> > To prevent other developers from wasting their precious time in
> > searching for this structure, add a comment to help them find it!
> > 
> > Cc: Al Viro <viro@ZenIV.linux.org.uk>
> > Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> > Signed-off-by: Steven "frustrated" Rostedt <rostedt@goodmis.org>
> 
> The cscope tool is your friend in this case, but nevertheless:

I use emacs, and the latest version of etags (or emacs) brings you to
each use case before it gets you to the define (which is really
annoying). Back in 2006 it use to work properly. I need to figure out
what changed :-/


> 
> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> 
> > diff --git a/include/linux/types.h b/include/linux/types.h
> > index 4d118ba..073e9a8 100644
> > --- a/include/linux/types.h
> > +++ b/include/linux/types.h
> > @@ -210,6 +210,9 @@ struct callback_head {
> >  	struct callback_head *next;
> >  	void (*func)(struct callback_head *head);
> >  };
> > +/*
> > + * Make "struct rcu_head {" seachable with this comment.

I've been told s/seachable/searchable/

Frustration fails me ;-)

-- Steve

> > + */
> >  #define rcu_head callback_head
> > 
> >  #endif /*  __ASSEMBLY__ */
> > 

Re: [PATCH] rcu: Make struct rcu_head searchable

[Andrew Morton]

On Wed, 13 Nov 2013 13:10:44 -0500 Steven Rostedt <rostedt@goodmis.org> wrote:

> On Wed, 13 Nov 2013 09:12:05 -0800
> "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:
> 
> > On Wed, Nov 13, 2013 at 12:02:25PM -0500, Steven Rostedt wrote:
> > > After wasting too much time trying to see where struct rcu_head was
> > > declared, I finally found it in include/linux/types.h as a define for
> > > callback_head!
> > > 
> > > To prevent other developers from wasting their precious time in
> > > searching for this structure, add a comment to help them find it!
> > > 
> > > Cc: Al Viro <viro@ZenIV.linux.org.uk>
> > > Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> > > Signed-off-by: Steven "frustrated" Rostedt <rostedt@goodmis.org>
> > 
> > The cscope tool is your friend in this case, but nevertheless:
> 
> I use emacs, and the latest version of etags (or emacs) brings you to
> each use case before it gets you to the define (which is really
> annoying). Back in 2006 it use to work properly. I need to figure out
> what changed :-/

That irritates me too.  Fortunately I just invented

(grep "#define" tags && grep -v "#define" tags) > tags.new

Re: [PATCH] rcu: Make struct rcu_head searchable

[Steven Rostedt]

On Wed, 13 Nov 2013 10:57:05 -0800
Andrew Morton <akpm@linux-foundation.org> wrote:


> That irritates me too.  Fortunately I just invented
> 
> (grep "#define" tags && grep -v "#define" tags) > tags.new

Unfortunately, TAGS doesn't work that way. Hmm, I could whip up a perl
script to do it for me though.

-- Steve