block: remove __bdevname

There is no good reason for __bdevname to exist.  Just open code
printing the string in the callers.  For three of them the format
string can be trivially merged into existing printk statements,
and in init/do_mounts.c we can at least do the scnprintf once at
the start of the function, and unconditional of CONFIG_BLOCK to
make the output for tiny configfs a little more helpful.

Acked-by: Theodore Ts'o <tytso@mit.edu> # for ext4
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

init/do_mounts.c

@@ -429,12 +429,10 @@ void __init mount_block_root(char *name, int flags)
 	struct page *page = alloc_page(GFP_KERNEL);
 	char *fs_names = page_address(page);
 	char *p;
-#ifdef CONFIG_BLOCK
 	char b[BDEVNAME_SIZE];
-#else
-	const char *b = name;
-#endif
 
+	scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
+		  MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
 	get_fs_names(fs_names);
 retry:
 	for (p = fs_names; *p; p += strlen(p)+1) {
@@ -451,9 +449,6 @@ retry:
 		 * and bad superblock on root device.
 		 * and give them a list of the available devices
 		 */
-#ifdef CONFIG_BLOCK
-		__bdevname(ROOT_DEV, b);
-#endif
 		printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
 				root_device_name, b, err);
 		printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
@@ -476,9 +471,6 @@ retry:
 	for (p = fs_names; *p; p += strlen(p)+1)
 		printk(" %s", p);
 	printk("\n");
-#ifdef CONFIG_BLOCK
-	__bdevname(ROOT_DEV, b);
-#endif
 	panic("VFS: Unable to mount root fs on %s", b);
 out:
 	put_page(page);