md/raid10: unify handling of write completion.

A write can complete at two different places:
1/ when the last member-device write completes, through
   raid10_end_write_request
2/ in make_request() when we remove the initial bias from ->remaining.

These two should do exactly the same thing and the comment says they
do, but they don't.

So factor the correct code out into a function and call it in both
places.  This makes the code much more similar to RAID1.

The difference is only significant if there is an error, and they
usually take a while, so it is unlikely that there will be an error
already when make_request is completing, so this is unlikely to cause
real problems.

Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 18 insertions, 20 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 8b29cd4f01c8..f6873fc8e5ee 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -337,6 +337,21 @@ static void close_write(r10bio_t *r10_bio)
         md_write_end(r10_bio->mddev);
 }
 
+static void one_write_done(r10bio_t *r10_bio)
+{
+        if (atomic_dec_and_test(&r10_bio->remaining)) {
+                if (test_bit(R10BIO_WriteError, &r10_bio->state))
+                        reschedule_retry(r10_bio);
+                else {
+                        close_write(r10_bio);
+                        if (test_bit(R10BIO_MadeGood, &r10_bio->state))
+                                reschedule_retry(r10_bio);
+                        else
+                                raid_end_bio_io(r10_bio);
+                }
+        }
+}
+
 static void raid10_end_write_request(struct bio *bio, int error)
 {
         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
@@ -387,17 +402,7 @@ static void raid10_end_write_request(struct bio *bio, int error)
          * Let's see if all mirrored write operations have finished
          * already.
          */
-        if (atomic_dec_and_test(&r10_bio->remaining)) {
-                if (test_bit(R10BIO_WriteError, &r10_bio->state))
-                        reschedule_retry(r10_bio);
-                else {
-                        close_write(r10_bio);
-                        if (test_bit(R10BIO_MadeGood, &r10_bio->state))
-                                reschedule_retry(r10_bio);
-                        else
-                                raid_end_bio_io(r10_bio);
-                }
-        }
+        one_write_done(r10_bio);
         if (dec_rdev)
                 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
 }
@@ -1127,15 +1132,8 @@ retry_write:
                 spin_unlock_irqrestore(&conf->device_lock, flags);
         }
 
-        if (atomic_dec_and_test(&r10_bio->remaining)) {
-                /* This matches the end of raid10_end_write_request() */
-                bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
-                                r10_bio->sectors,
-                                !test_bit(R10BIO_Degraded, &r10_bio->state),
-                                0);
-                md_write_end(mddev);
-                raid_end_bio_io(r10_bio);
-        }
+        /* Remove the bias on 'remaining' */
+        one_write_done(r10_bio);
 
         /* In case raid10d snuck in to freeze_array */
         wake_up(&conf->wait_barrier);