hostfs: fix a duplicated global function name

fs/hostfs/hostfs_user.c defines do_readlink() as non-static, and so does
fs/xfs/linux-2.6/xfs_ioctl.c when CONFIG_XFS_DEBUG=y.  So rename
do_readlink() in hostfs to hostfs_do_readlink().

I think it's better if XFS guys will also rename their do_readlink(),
it's not necessary to use such a general name.
Signed-off-by: WANG Cong <wangcong@zeuux.org>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/hostfs/hostfs.h

@@ -81,7 +81,7 @@ extern int do_rmdir(const char *file);
 extern int do_mknod(const char *file, int mode, unsigned int major,
 		    unsigned int minor);
 extern int link_file(const char *from, const char *to);
-extern int do_readlink(char *file, char *buf, int size);
+extern int hostfs_do_readlink(char *file, char *buf, int size);
 extern int rename_file(char *from, char *to);
 extern int do_statfs(char *root, long *bsize_out, long long *blocks_out,
 		     long long *bfree_out, long long *bavail_out,

fs/hostfs/hostfs_kern.c

@@ -168,7 +168,7 @@ static char *follow_link(char *link)
 		if (name == NULL)
 			goto out;
 
-		n = do_readlink(link, name, len);
+		n = hostfs_do_readlink(link, name, len);
 		if (n < len)
 			break;
 		len *= 2;
@@ -943,7 +943,7 @@ int hostfs_link_readpage(struct file *file, struct page *page)
 	name = inode_name(page->mapping->host, 0);
 	if (name == NULL)
 		return -ENOMEM;
-	err = do_readlink(name, buffer, PAGE_CACHE_SIZE);
+	err = hostfs_do_readlink(name, buffer, PAGE_CACHE_SIZE);
 	kfree(name);
 	if (err == PAGE_CACHE_SIZE)
 		err = -E2BIG;

fs/hostfs/hostfs_user.c

@@ -377,7 +377,7 @@ int link_file(const char *to, const char *from)
 	return 0;
 }
 
-int do_readlink(char *file, char *buf, int size)
+int hostfs_do_readlink(char *file, char *buf, int size)
 {
 	int n;