proc: introduce proc_create_single{,_data}

Variants of proc_create{,_data} that directly take a seq_file show
callback and drastically reduces the boilerplate code in the callers.

All trivial callers converted over.

Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index d4e8c49..dcf5ea2 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -208,19 +208,6 @@
 	return 0;
 }
 
-static int fake_ide_media_proc_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, fake_ide_media_proc_show, NULL);
-}
-
-static const struct file_operations fake_ide_media_proc_fops = {
-	.owner		= THIS_MODULE,
-	.open		= fake_ide_media_proc_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
-
 static void make_ide_entries(const char *dev_name)
 {
 	struct proc_dir_entry *dir, *ent;
@@ -231,7 +218,8 @@
 	dir = proc_mkdir(dev_name, proc_ide);
 	if(!dir) return;
 
-	ent = proc_create("media", S_IRUGO, dir, &fake_ide_media_proc_fops);
+	ent = proc_create_single("media", S_IRUGO, dir,
+			fake_ide_media_proc_show);
 	if(!ent) return;
 	snprintf(name, sizeof(name), "ide0/%s", dev_name);
 	proc_symlink(dev_name, proc_ide_root, name);