On Mon, Dec 09, 2013 at 09:43:16AM +0800, Ethan Zhao wrote: > On Sun, Dec 8, 2013 at 10:01 PM, Greg KH <[email protected]> wrote: > > On Sun, Dec 08, 2013 at 07:31:02PM +0800, ethan.zhao wrote: > >> Should check debugfs initialization with debugfs_initialized() before > >> using it, > >> Because if it isn't initialized, the return value of fake > >> debugfs_create_dir() etc > >> functions would be ERR_PTR(-ENODEV), checking with NULL will not work. > > > > So? It should "just work" without this check, right? What happens if > > your patch isn't applied and debugfs isn't enabled? > > If debugfs isn't configured, debugfs_initialized() and other > functions are defined as following, > > static inline bool debugfs_initialized(void) > { > return false; > } > > 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); > } > > static inline struct dentry *debugfs_create_dir(const char *name, > struct dentry *parent) > { > return ERR_PTR(-ENODEV); > } > > And the checking code in xen\debugfs.c xen_init_debugfs() will not > work, the return value is not NULL. > d_xen_debug = debugfs_create_dir("xen", NULL); > > if (!d_xen_debug) > pr_warning("Could not create 'xen' debugfs directory\n");
Which is just fine, what is wrong with this? > > > > greg k-h > > > >> Signed-off-by: ethan.zhao <[email protected]> > > > > Please put your "real" name here, not one with a '.' in it. > > The real name used in company is [email protected], but I > couldn't send and receive mails of > community with that mailbox for some reason you may know. I mean the "ethan.zhao" part, it should be "Ethan Zhao" :) thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
