[PATCH 1/2] md/raid1: fix the comparing region of interval tree

[Xiao Ni <xni@redhat.com>]

Interval tree uses [start, end] as a region which stores in the tree.
In raid1, it uses the wrong end value. For example:
bio(A,B) is too big and needs to be split to bio1(A,C-1), bio2(C,B).
The region of bio1 is [A,C] and the region of bio2 is [C,B]. So bio1 and
bio2 overlap which is not right.

Fix this problem by using right end value of the region.

Fixes: d0d2d8ba0494 ("md/raid1: introduce wait_for_serialization")
Signed-off-by: Xiao Ni <xni@redhat.com>
---
 drivers/md/raid1.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 181400e147c0..be2565dee420 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -62,7 +62,7 @@ static int check_and_add_serial(struct md_rdev *rdev, struct r1bio *r1_bio,
 	unsigned long flags;
 	int ret = 0;
 	sector_t lo = r1_bio->sector;
-	sector_t hi = lo + r1_bio->sectors;
+	sector_t hi = lo + r1_bio->sectors - 1;
 	struct serial_in_rdev *serial = &rdev->serial[idx];
 
 	spin_lock_irqsave(&serial->serial_lock, flags);
@@ -452,7 +452,7 @@ static void raid1_end_write_request(struct bio *bio)
 	int mirror = find_bio_disk(r1_bio, bio);
 	struct md_rdev *rdev = conf->mirrors[mirror].rdev;
 	sector_t lo = r1_bio->sector;
-	sector_t hi = r1_bio->sector + r1_bio->sectors;
+	sector_t hi = r1_bio->sector + r1_bio->sectors - 1;
 	bool ignore_error = !raid1_should_handle_error(bio) ||
 		(bio->bi_status && bio_op(bio) == REQ_OP_DISCARD);
 
-- 
2.50.1 (Apple Git-155)