RE: [PATCH RFCv2 1/3] fs: introduce helper d_path_fast()

[Justin He <Justin.He@arm.com>]

> -----Original Message-----
> From: Matthew Wilcox <willy@infradead.org>
> Sent: Friday, May 28, 2021 8:52 PM
> To: Justin He <Justin.He@arm.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>; Petr Mladek
> <pmladek@suse.com>; Steven Rostedt <rostedt@goodmis.org>; Sergey
> Senozhatsky <senozhatsky@chromium.org>; Andy Shevchenko
> <andriy.shevchenko@linux.intel.com>; Rasmus Villemoes
> <linux@rasmusvillemoes.dk>; Jonathan Corbet <corbet@lwn.net>; Alexander
> Viro <viro@zeniv.linux.org.uk>; Luca Coelho <luciano.coelho@intel.com>;
> Kalle Valo <kvalo@codeaurora.org>; David S. Miller <davem@davemloft.net>;
> Jakub Kicinski <kuba@kernel.org>; Heiko Carstens <hca@linux.ibm.com>;
> Vasily Gorbik <gor@linux.ibm.com>; Christian Borntraeger
> <borntraeger@de.ibm.com>; Johannes Berg <johannes.berg@intel.com>; linux-
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> Subject: Re: [PATCH RFCv2 1/3] fs: introduce helper d_path_fast()
>
> On Fri, May 28, 2021 at 07:39:49PM +0800, Jia He wrote:
> > +/**
> > + * d_path_fast - fast return the full path of a dentry without taking
> > + * any seqlock/spinlock. This helper is typical for debugging purpose
> > + */
> > +char *d_path_fast(const struct path *path, char *buf, int buflen)
>
> I'd suggest calling it d_path_unsafe().  Otherwise people will call it
> instead of d_path because who doesn't like fast?
>
Okay, thanks

> > +{
> > +   struct path root;
> > +   struct mount *mnt = real_mount(path->mnt);
> > +   DECLARE_BUFFER(b, buf, buflen);
> > +
> > +   rcu_read_lock();
> > +   get_fs_root_rcu(current->fs, &root);
> > +
> > +   prepend(&b, "", 1);
> > +   __prepend_path(path->dentry, mnt, &root, &b);
> > +   rcu_read_unlock();
> > +
> > +   return extract_string(&b);
> > +}
> > +EXPORT_SYMBOL(d_path_fast);
>
> Why export it?  What module needs this?
Okay, indeed

--
Cheers,
Justin (Jia He)


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