Re: [PATCH] pstore/ftrace: Convert to its own enable/disable debugfs knob

On Wed, Jul 18, 2012 at 10:12:44AM -0700, Stephen Boyd wrote:

On 07/17/12 20:47, Anton Vorontsov wrote:

...

• file = debugfs_create_file("record_ftrace", 0600, dir, NULL,

• 		   &pstore_knob_fops);
  

• if (IS_ERR_OR_NULL(file)) {

• err = PTR_ERR(file);
  

• pr_err("%s: unable to create pstore/ftrace file: %d\n",
  

•        __func__, err);
  

• goto err_file;
  

• }

debugfs only returns NULL on failure.

Well, techincally, with DEBUG_FS=y, yes. (And we have dependency on it.)

But see include/linux/debugfs.h for DEBUG_FS=n case:

static inline struct dentry *debugfs_create_file(const char *name, umode_t mode, struct dentry *parent, void *data, const struct file_operations *fops) { return ERR_PTR(-ENODEV); }

So, I think it is fine to check for IS_ERR_OR_NULL(), although today it's always NULL for our case, true.

Thanks,