md/raid1: tidy up new functions: process_checks and fix_sync_read_error.

These changes are mostly cosmetic:

1/ change mddev->raid_disks to conf->raid_disks because the later is
   technically safer, though in current practice it doesn't matter in
   this particular context.
2/ Rearrange two for / if loops to have an early 'continue' so the
   body of the 'if' doesn't need to be indented so much.
Signed-off-by: NeilBrown <neilb@suse.de>

drivers/md/raid1.c

@@ -1203,6 +1203,7 @@ static int fix_sync_read_error(r1bio_t *r1_bio)
 		int d = r1_bio->read_disk;
 		int success = 0;
 		mdk_rdev_t *rdev;
+		int start;
 
 		if (s > (PAGE_SIZE>>9))
 			s = PAGE_SIZE >> 9;
@@ -1227,10 +1228,22 @@ static int fix_sync_read_error(r1bio_t *r1_bio)
 				d = 0;
 		} while (!success && d != r1_bio->read_disk);
 
-		if (success) {
-			int start = d;
+		if (!success) {
+			char b[BDEVNAME_SIZE];
+			/* Cannot read from anywhere, array is toast */
+			md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
+			printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
+			       " for block %llu\n",
+			       mdname(mddev),
+			       bdevname(bio->bi_bdev, b),
+			       (unsigned long long)r1_bio->sector);
+			md_done_sync(mddev, r1_bio->sectors, 0);
+			put_buf(r1_bio);
+			return 0;
+		}
+
+		start = d;
 		/* write it back and re-read */
-			set_bit(R1BIO_Uptodate, &r1_bio->state);
 		while (d != r1_bio->read_disk) {
 			if (d == 0)
 				d = conf->raid_disks;
@@ -1238,13 +1251,16 @@ static int fix_sync_read_error(r1bio_t *r1_bio)
 			if (r1_bio->bios[d]->bi_end_io != end_sync_read)
 				continue;
 			rdev = conf->mirrors[d].rdev;
-				atomic_add(s, &rdev->corrected_errors);
 			if (sync_page_io(rdev,
 					 sect,
 					 s<<9,
 					 bio->bi_io_vec[idx].bv_page,
-						 WRITE, false) == 0)
+					 WRITE, false) == 0) {
+				r1_bio->bios[d]->bi_end_io = NULL;
+				rdev_dec_pending(rdev, mddev);
 				md_error(mddev, rdev);
+			} else
+				atomic_add(s, &rdev->corrected_errors);
 		}
 		d = start;
 		while (d != r1_bio->read_disk) {
@@ -1261,23 +1277,11 @@ static int fix_sync_read_error(r1bio_t *r1_bio)
 					 READ, false) == 0)
 				md_error(mddev, rdev);
 		}
-		} else {
-			char b[BDEVNAME_SIZE];
-			/* Cannot read from anywhere, array is toast */
-			md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
-			printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
-			       " for block %llu\n",
-			       mdname(mddev),
-			       bdevname(bio->bi_bdev, b),
-			       (unsigned long long)r1_bio->sector);
-			md_done_sync(mddev, r1_bio->sectors, 0);
-			put_buf(r1_bio);
-			return 0;
-		}
 		sectors -= s;
 		sect += s;
 		idx ++;
 	}
+	set_bit(R1BIO_Uptodate, &r1_bio->state);
 	return 1;
 }
 
@@ -1296,7 +1300,7 @@ static int process_checks(r1bio_t *r1_bio)
 	int i;
 
 	if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
-		for (i=0; i<mddev->raid_disks; i++)
+		for (i=0; i < conf->raid_disks; i++)
 			if (r1_bio->bios[i]->bi_end_io == end_sync_read)
 				md_error(mddev, conf->mirrors[i].rdev);
 
@@ -1304,7 +1308,7 @@ static int process_checks(r1bio_t *r1_bio)
 		put_buf(r1_bio);
 		return -1;
 	}
-	for (primary=0; primary<mddev->raid_disks; primary++)
+	for (primary = 0; primary < conf->raid_disks; primary++)
 		if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
 		    test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
 			r1_bio->bios[primary]->bi_end_io = NULL;
@@ -1312,12 +1316,15 @@ static int process_checks(r1bio_t *r1_bio)
 			break;
 		}
 	r1_bio->read_disk = primary;
-	for (i=0; i<mddev->raid_disks; i++)
-		if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
+	for (i = 0; i < conf->raid_disks; i++) {
 		int j;
 		int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
 		struct bio *pbio = r1_bio->bios[primary];
 		struct bio *sbio = r1_bio->bios[i];
+		int size;
+
+		if (r1_bio->bios[i]->bi_end_io != end_sync_read)
+			continue;
 
 		if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
 			for (j = vcnt; j-- ; ) {
@@ -1335,11 +1342,12 @@ static int process_checks(r1bio_t *r1_bio)
 			mddev->resync_mismatches += r1_bio->sectors;
 		if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
 			      && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
+			/* No need to write to this device. */
 			sbio->bi_end_io = NULL;
 			rdev_dec_pending(conf->mirrors[i].rdev, mddev);
-			} else {
+			continue;
+		}
 		/* fixup the bio for reuse */
-				int size;
 		sbio->bi_vcnt = vcnt;
 		sbio->bi_size = r1_bio->sectors << 9;
 		sbio->bi_idx = 0;
@@ -1364,8 +1372,6 @@ static int process_checks(r1bio_t *r1_bio)
 			       page_address(pbio->bi_io_vec[j].bv_page),
 			       PAGE_SIZE);
 		}
-
-			}
 	}
 	return 0;
 }