dm/ebs: Change 'int rw' into 'enum req_op op'

Improve static type checking by using type 'enum req_op' instead of 'int'.
Make the role of the 'rw' arguments more clear by renaming these into
'op' (operation). This patch does not change any functionality since
REQ_OP_READ = READ = 0 and REQ_OP_WRITE = WRITE = 1.

Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Heinz Mauelshagen <heinzm@redhat.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-25-bvanassche@acm.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/dm-ebs-target.c

@@ -61,7 +61,8 @@ static inline bool __ebs_check_bs(unsigned int bs)
  *
  * copy blocks between bufio blocks and bio vector's (partial/overlapping) pages.
  */
-static int __ebs_rw_bvec(struct ebs_c *ec, int rw, struct bio_vec *bv, struct bvec_iter *iter)
+static int __ebs_rw_bvec(struct ebs_c *ec, enum req_op op, struct bio_vec *bv,
+			 struct bvec_iter *iter)
 {
 	int r = 0;
 	unsigned char *ba, *pa;
@@ -81,7 +82,7 @@ static int __ebs_rw_bvec(struct ebs_c *ec, int rw, struct bio_vec *bv, struct bv
 		cur_len = min(dm_bufio_get_block_size(ec->bufio) - buf_off, bv_len);
 
 		/* Avoid reading for writes in case bio vector's page overwrites block completely. */
-		if (rw == READ || buf_off || bv_len < dm_bufio_get_block_size(ec->bufio))
+		if (op == REQ_OP_READ || buf_off || bv_len < dm_bufio_get_block_size(ec->bufio))
 			ba = dm_bufio_read(ec->bufio, block, &b);
 		else
 			ba = dm_bufio_new(ec->bufio, block, &b);
@@ -95,7 +96,7 @@ static int __ebs_rw_bvec(struct ebs_c *ec, int rw, struct bio_vec *bv, struct bv
 		} else {
 			/* Copy data to/from bio to buffer if read/new was successful above. */
 			ba += buf_off;
-			if (rw == READ) {
+			if (op == REQ_OP_READ) {
 				memcpy(pa, ba, cur_len);
 				flush_dcache_page(bv->bv_page);
 			} else {
@@ -117,14 +118,14 @@ static int __ebs_rw_bvec(struct ebs_c *ec, int rw, struct bio_vec *bv, struct bv
 }
 
 /* READ/WRITE: iterate bio vector's copying between (partial) pages and bufio blocks. */
-static int __ebs_rw_bio(struct ebs_c *ec, int rw, struct bio *bio)
+static int __ebs_rw_bio(struct ebs_c *ec, enum req_op op, struct bio *bio)
 {
 	int r = 0, rr;
 	struct bio_vec bv;
 	struct bvec_iter iter;
 
 	bio_for_each_bvec(bv, bio, iter) {
-		rr = __ebs_rw_bvec(ec, rw, &bv, &iter);
+		rr = __ebs_rw_bvec(ec, op, &bv, &iter);
 		if (rr)
 			r = rr;
 	}
@@ -205,10 +206,10 @@ static void __ebs_process_bios(struct work_struct *ws)
 	bio_list_for_each(bio, &bios) {
 		r = -EIO;
 		if (bio_op(bio) == REQ_OP_READ)
-			r = __ebs_rw_bio(ec, READ, bio);
+			r = __ebs_rw_bio(ec, REQ_OP_READ, bio);
 		else if (bio_op(bio) == REQ_OP_WRITE) {
 			write = true;
-			r = __ebs_rw_bio(ec, WRITE, bio);
+			r = __ebs_rw_bio(ec, REQ_OP_WRITE, bio);
 		} else if (bio_op(bio) == REQ_OP_DISCARD) {
 			__ebs_forget_bio(ec, bio);
 			r = __ebs_discard_bio(ec, bio);