Re: [PATCH v4 0/3] libfs,xenfs: replace /proc/xen/xenbus with a symlink

[Al Viro]

On Fri, Oct 28, 2016 at 04:52:36PM +0100, David Vrabel wrote:
> Using /proc/xen/xenbus can cause deadlocks on the atomic file position
> mutex since this file should behave like a character device and not a
> regular file.  This is easiest to achive by making it a symlink to the
> existing /dev/xen/xenbus device.

What.  The.  Hell?  What's wrong with simply adding
	file->f_mode &= ~FMODE_ATOMIC_POS;	/* cdev-style semantics */

in the ->open() of those files, rather than going through all those
convolutions?