Commit 31b07093 authored Apr 09, 2009 by KOSAKI Motohiro Committed by Greg Kroah-Hartman Apr 16, 2009

proc: mounts_poll() make consistent to mdstat_poll

In recently sysfs_poll discussion, Neil Brown pointed out /proc/mounts
also should be fixed.

SUSv3 says "Regular files shall always poll TRUE for reading and
writing".  see
http://www.opengroup.org/onlinepubs/009695399/functions/poll.html



Then, mounts_poll()'s default should be "POLLIN | POLLRDNORM".  it mean
always readable.

In addition, event trigger should use "POLLERR | POLLPRI" instead
POLLERR.  it makes consistent to mdstat_poll() and sysfs_poll(). and,
select(2) can handle POLLPRI easily.


Reported-by: Neil Brown <neilb@suse.de>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

parent 1af3557a

fs/proc/base.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -648,14 +648,14 @@ static unsigned mounts_poll(struct file file, poll_table wait)
		{
		struct proc_mounts *p = file->private_data;
		struct mnt_namespace *ns = p->ns;
		unsigned res = 0;
		unsigned res = POLLIN \| POLLRDNORM;

		poll_wait(file, &ns->poll, wait);

		spin_lock(&vfsmount_lock);
		if (p->event != ns->event) {
		p->event = ns->event;
		res = POLLERR;
		res \|= POLLERR \| POLLPRI;
		}
		spin_unlock(&vfsmount_lock);

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