lkml.org 
[lkml]   [2011]   [Feb]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH RFC tip/core/rcu 14/14] rcu: Add boosting to TREE_PREEMPT_RCU tracing
On Wed, Feb 23, 2011 at 11:07:20AM +0800, Lai Jiangshan wrote:
> On 02/23/2011 09:39 AM, Paul E. McKenney wrote:
> > rcudir = debugfs_create_dir("rcu", NULL);
> > - if (!rcudir)
> > + if (IS_ERR_VALUE(rcudir))
> > goto free_out;
>
> if !defined(CONFIG_DEBUG_FS)
> debugfs_create_xxx() returns ERR_PTR(-ENODEV);
> else
> debugfs_create_xxx() returns NULL when failed.
>
> Since TREE_RCU_TRACE selects DEBUG_FS, "if (!rcudir)" is correct,
> we don't need to change it.

Yeah, but this really needs to be less fragile. And yes, I do appear
to have broken it in the NULL-pointer case. And who came up with the
API above, anyway? It is an accident waiting to happen.

All whining aside, I need something like the following, correct?

#define IS_ERR_VALUE_OR_NULL(x) \
unlikely((x) - 1 >= (unsigned long)(-MAX_ERRNO-1)

Thanx, Paul

> > retval = debugfs_create_file("rcudata", 0444, rcudir,
> > NULL, &rcudata_fops);
> > - if (!retval)
> > + if (IS_ERR_VALUE(retval))
> > goto free_out;
> >
> > retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
> > NULL, &rcudata_csv_fops);
> > - if (!retval)
> > + if (IS_ERR_VALUE(retval))
> > + goto free_out;
> > +
> > + retval = rcu_boost_trace_create_file(rcudir);
> > + if (retval)
> > goto free_out;
> >
> > retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
> > - if (!retval)
> > + if (IS_ERR_VALUE(retval))
> > goto free_out;
> >
> > retval = debugfs_create_file("rcuhier", 0444, rcudir,
> > NULL, &rcuhier_fops);
> > - if (!retval)
> > + if (IS_ERR_VALUE(retval))
> > goto free_out;
> >
> > retval = debugfs_create_file("rcu_pending", 0444, rcudir,
> > NULL, &rcu_pending_fops);
> > - if (!retval)
> > + if (IS_ERR_VALUE(retval))
> > goto free_out;
> > return 0;
> > free_out:
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/


\
 
 \ /
  Last update: 2011-02-23 17:33    [W:0.110 / U:0.460 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site