[PATCH] add romfs_get_size()

[Yasushi SHOJI <yashi@atmark-techno.com>]

Many embedded linux products have been using romfs and it's still
growing.  most, if not all, of them implement thier own way to check
its romfs size.

this patch provides this commonly used function.

Signed-off-by: Yasushi SHOJI <yashi@atmark-techno.com>
---
diff --git a/fs/romfs/inode.c b/fs/romfs/inode.c
--- a/fs/romfs/inode.c
+++ b/fs/romfs/inode.c
@@ -84,6 +84,17 @@ struct romfs_inode_info {
 	struct inode vfs_inode;
 };
 
+int romfs_get_size(struct romfs_super_block *rsb)
+{
+	int sz = be32_to_cpu(rsb->size);
+	if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1
+	    || sz < ROMFH_SIZE) {
+		sz = -1;
+	}
+	return sz;
+}
+EXPORT_SYMBOL(romfs_get_size);
+
 /* instead of private superblock data */
 static inline unsigned long romfs_maxsize(struct super_block *sb)
 {
@@ -132,9 +143,8 @@ static int romfs_fill_super(struct super
 	}
 
 	rsb = (struct romfs_super_block *)bh->b_data;
-	sz = be32_to_cpu(rsb->size);
-	if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1
-	   || sz < ROMFH_SIZE) {
+	sz = romfs_get_size(rsb);
+	if (sz == -1) {
 		if (!silent)
 			printk ("VFS: Can't find a romfs filesystem on dev "
 				"%s.\n", s->s_id);
diff --git a/include/linux/romfs_fs.h b/include/linux/romfs_fs.h
--- a/include/linux/romfs_fs.h
+++ b/include/linux/romfs_fs.h
@@ -55,7 +55,7 @@ struct romfs_inode {
 
 #ifdef __KERNEL__
 
-/* Not much now */
+int romfs_get_size(struct romfs_super_block *rsb);
 
 #endif /* __KERNEL__ */
 #endif