proc: return -ENOMEM when inode allocation failed

If proc_get_inode() returns NULL then presumably it encountered memory
exhaustion.  proc_lookup_de() should return -ENOMEM in this case, not
-EINVAL.
Signed-off-by: Nyan <clouds.yan@gmail.com>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/proc/generic.c

@@ -427,7 +427,7 @@ struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
 		if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
 			pde_get(de);
 			spin_unlock(&proc_subdir_lock);
-			error = -EINVAL;
+			error = -ENOMEM;
 			inode = proc_get_inode(dir->i_sb, de);
 			goto out_unlock;
 		}