blk-core: use BIO list management functions

Now that the bio list management stuff is generic, convert
generic_make_request to use bio lists instead of its own private bio
list implementation.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 78efe7c..7eb8297 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -97,7 +97,7 @@
 struct exec_domain;
 struct futex_pi_state;
 struct robust_list_head;
-struct bio;
+struct bio_list;
 struct fs_struct;
 struct bts_context;
 struct perf_event_context;
@@ -1466,7 +1466,7 @@
 	void *journal_info;
 
 /* stacked block device info */
-	struct bio *bio_list, **bio_tail;
+	struct bio_list *bio_list;
 
 /* VM state */
 	struct reclaim_state *reclaim_state;