bio-integrity: cleanup adding integrity pages to bip's bvec.

bio_integrity_add_page() returns the add length if successful, else 0,
just as bio_add_page.  Simply check return value checking in
bio_integrity_prep to not deal with a > 0 but < len case that can't
happen.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jinyoung Choi <j-young.choi@samsung.com>
Tested-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20230803025058epcms2p5a4d0db5da2ad967668932d463661c633@epcms2p5
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/bio-integrity.c

@@ -252,27 +252,18 @@ bool bio_integrity_prep(struct bio *bio)
 
 	/* Map it */
 	offset = offset_in_page(buf);
-	for (i = 0 ; i < nr_pages ; i++) {
-		int ret;
+	for (i = 0; i < nr_pages && len > 0; i++) {
 		bytes = PAGE_SIZE - offset;
 
-		if (len <= 0)
-			break;
-
 		if (bytes > len)
 			bytes = len;
 
-		ret = bio_integrity_add_page(bio, virt_to_page(buf),
-					     bytes, offset);
-
-		if (ret == 0) {
+		if (bio_integrity_add_page(bio, virt_to_page(buf),
+					   bytes, offset) < bytes) {
 			printk(KERN_ERR "could not attach integrity payload\n");
 			goto err_end_io;
 		}
 
-		if (ret < bytes)
-			break;
-
 		buf += bytes;
 		len -= bytes;
 		offset = 0;
@@ -291,7 +282,6 @@ bool bio_integrity_prep(struct bio *bio)
 	bio->bi_status = BLK_STS_RESOURCE;
 	bio_endio(bio);
 	return false;
-
 }
 EXPORT_SYMBOL(bio_integrity_prep);