md: raid1: retrieve page from pre-allocated resync page array

Now one page array is allocated for each resync bio, and we can
retrieve page from this table directly.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Shaohua Li <shli@fb.com>

drivers/md/raid1.c

@@ -1973,6 +1973,7 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
 	struct mddev *mddev = r1_bio->mddev;
 	struct r1conf *conf = mddev->private;
 	struct bio *bio = r1_bio->bios[r1_bio->read_disk];
+	struct page **pages = get_resync_pages(bio)->pages;
 	sector_t sect = r1_bio->sector;
 	int sectors = r1_bio->sectors;
 	int idx = 0;
@@ -2006,7 +2007,7 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
 				 */
 				rdev = conf->mirrors[d].rdev;
 				if (sync_page_io(rdev, sect, s<<9,
-						 bio->bi_io_vec[idx].bv_page,
+						 pages[idx],
 						 REQ_OP_READ, 0, false)) {
 					success = 1;
 					break;
@@ -2061,7 +2062,7 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
 				continue;
 			rdev = conf->mirrors[d].rdev;
 			if (r1_sync_page_io(rdev, sect, s,
-					    bio->bi_io_vec[idx].bv_page,
+					    pages[idx],
 					    WRITE) == 0) {
 				r1_bio->bios[d]->bi_end_io = NULL;
 				rdev_dec_pending(rdev, mddev);
@@ -2076,7 +2077,7 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
 				continue;
 			rdev = conf->mirrors[d].rdev;
 			if (r1_sync_page_io(rdev, sect, s,
-					    bio->bi_io_vec[idx].bv_page,
+					    pages[idx],
 					    READ) != 0)
 				atomic_add(s, &rdev->corrected_errors);
 		}
@@ -2152,6 +2153,8 @@ static void process_checks(struct r1bio *r1_bio)
 		struct bio *pbio = r1_bio->bios[primary];
 		struct bio *sbio = r1_bio->bios[i];
 		int error = sbio->bi_error;
+		struct page **ppages = get_resync_pages(pbio)->pages;
+		struct page **spages = get_resync_pages(sbio)->pages;
 
 		if (sbio->bi_end_io != end_sync_read)
 			continue;
@@ -2160,11 +2163,8 @@ static void process_checks(struct r1bio *r1_bio)
 
 		if (!error) {
 			for (j = vcnt; j-- ; ) {
-				struct page *p, *s;
-				p = pbio->bi_io_vec[j].bv_page;
-				s = sbio->bi_io_vec[j].bv_page;
-				if (memcmp(page_address(p),
-					   page_address(s),
+				if (memcmp(page_address(ppages[j]),
+					   page_address(spages[j]),
 					   sbio->bi_io_vec[j].bv_len))
 					break;
 			}