block: convert to bio_first_bvec_all & bio_first_page_all

This patch converts to bio_first_bvec_all() & bio_first_page_all() for
retrieving the 1st bvec/page, and prepares for supporting multipage bvec.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 516fa0d..455f086 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -56,7 +56,7 @@
 	int i;
 
 #ifdef CONFIG_F2FS_FAULT_INJECTION
-	if (time_to_inject(F2FS_P_SB(bio->bi_io_vec->bv_page), FAULT_IO)) {
+	if (time_to_inject(F2FS_P_SB(bio_first_page_all(bio)), FAULT_IO)) {
 		f2fs_show_injection_info(FAULT_IO);
 		bio->bi_status = BLK_STS_IOERR;
 	}