proc: return on proc_readdir error
proc: return on proc_readdir error

Commit f0c3b5093add ("[readdir] convert procfs") introduced a bug on the
listing of the proc file-system.  The return value of proc_readdir()
isn't tested anymore in the proc_root_readdir function.

This lead to an "interesting" behaviour when we are using the getdents()
system call with a buffer too small: instead of failing, it returns the
first entries of /proc (enough to fill the given buffer), plus the PID
directories.

This is not triggered on glibc (as getdents is called with a 32KB
buffer), but on uclibc, the buffer size is only 1KB, thus some proc
entries are missing.

See https://lkml.org/lkml/2013/8/12/288 for more background.

Signed-off-by: Richard Genoud <9cfb506ffc11a9bdfddeea4cef2a4c9d35dfe20c@gmail.com>
Cc: Al Viro <de609eb4d5d70b1d38ec6642adbfc33a2781f63c@zeniv.linux.org.uk>
Cc: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs