fs/mpage: Use the new blk_opf_t type

Improve static type checking by using the new blk_opf_t type for the
combination of a block layer request with block layer request flags.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-50-bvanassche@acm.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/mpage.c

@@ -145,13 +145,13 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 	struct block_device *bdev = NULL;
 	int length;
 	int fully_mapped = 1;
-	int op = REQ_OP_READ;
+	blk_opf_t opf = REQ_OP_READ;
 	unsigned nblocks;
 	unsigned relative_block;
 	gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
 
 	if (args->is_readahead) {
-		op |= REQ_RAHEAD;
+		opf |= REQ_RAHEAD;
 		gfp |= __GFP_NORETRY | __GFP_NOWARN;
 	}
 
@@ -269,7 +269,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 								page))
 				goto out;
 		}
-		args->bio = bio_alloc(bdev, bio_max_segs(args->nr_pages), op,
+		args->bio = bio_alloc(bdev, bio_max_segs(args->nr_pages), opf,
 				      gfp);
 		if (args->bio == NULL)
 			goto confused;