afs: use bvec_set_folio to initialize a bvec

Use the bvec_set_folio helper to initialize a bvec.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20230203150634.3199647-12-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/afs/write.c

@@ -992,7 +992,7 @@ int afs_launder_folio(struct folio *folio)
 {
 	struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio));
 	struct iov_iter iter;
-	struct bio_vec bv[1];
+	struct bio_vec bv;
 	unsigned long priv;
 	unsigned int f, t;
 	int ret = 0;
@@ -1008,10 +1008,8 @@ int afs_launder_folio(struct folio *folio)
 			t = afs_folio_dirty_to(folio, priv);
 		}
 
-		bv[0].bv_page = &folio->page;
-		bv[0].bv_offset = f;
-		bv[0].bv_len = t - f;
-		iov_iter_bvec(&iter, ITER_SOURCE, bv, 1, bv[0].bv_len);
+		bvec_set_folio(&bv, folio, t - f, f);
+		iov_iter_bvec(&iter, ITER_SOURCE, &bv, 1, bv.bv_len);
 
 		trace_afs_folio_dirty(vnode, tracepoint_string("launder"), folio);
 		ret = afs_store_data(vnode, &iter, folio_pos(folio) + f, true);