From 77d39bae450ea025af2d86ba154fc4d741686b47 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 1 May 2006 12:15:45 -0700
Subject: [PATCH] --- yaml --- r: 26387 b: refs/heads/master c:
 e0a33270ed0e8e00cbb882a33d21e1f92aac0ceb h: refs/heads/master i:   26385:
 72bb9fe0e21df6f171dc9996bd9e56c55ebe84b7   26383:
 9decdb53ede4edf49a85d4565bbea5e3ffd0ee4f v: v3

---
 [refs]                    |  2 +-
 trunk/drivers/md/raid10.c | 44 ++++++++++++++++++++++++++-------------
 2 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/[refs] b/[refs]
index 3b7a3ffe2ccd..14cedf9d43cd 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: df30d0f4ca3c41b60068232d6de9d58be88436f0
+refs/heads/master: e0a33270ed0e8e00cbb882a33d21e1f92aac0ceb
diff --git a/trunk/drivers/md/raid10.c b/trunk/drivers/md/raid10.c
index ddc1dfc4d3d2..1440935414e6 100644
--- a/trunk/drivers/md/raid10.c
+++ b/trunk/drivers/md/raid10.c
@@ -1407,36 +1407,45 @@ static void raid10d(mddev_t *mddev)
 				if (s > (PAGE_SIZE>>9))
 					s = PAGE_SIZE >> 9;
 
+				rcu_read_lock();
 				do {
 					int d = r10_bio->devs[sl].devnum;
-					rdev = conf->mirrors[d].rdev;
+					rdev = rcu_dereference(conf->mirrors[d].rdev);
 					if (rdev &&
-					    test_bit(In_sync, &rdev->flags) &&
-					    sync_page_io(rdev->bdev,
-							 r10_bio->devs[sl].addr +
-							 sect + rdev->data_offset,
-							 s<<9,
-							 conf->tmppage, READ))
-						success = 1;
-					else {
-						sl++;
-						if (sl == conf->copies)
-							sl = 0;
+					    test_bit(In_sync, &rdev->flags)) {
+						atomic_inc(&rdev->nr_pending);
+						rcu_read_unlock();
+						success = sync_page_io(rdev->bdev,
+								       r10_bio->devs[sl].addr +
+								       sect + rdev->data_offset,
+								       s<<9,
+								       conf->tmppage, READ);
+						rdev_dec_pending(rdev, mddev);
+						rcu_read_lock();
+						if (success)
+							break;
 					}
+					sl++;
+					if (sl == conf->copies)
+						sl = 0;
 				} while (!success && sl != r10_bio->read_slot);
+				rcu_read_unlock();
 
 				if (success) {
 					int start = sl;
 					/* write it back and re-read */
+					rcu_read_lock();
 					while (sl != r10_bio->read_slot) {
 						int d;
 						if (sl==0)
 							sl = conf->copies;
 						sl--;
 						d = r10_bio->devs[sl].devnum;
-						rdev = conf->mirrors[d].rdev;
+						rdev = rcu_dereference(conf->mirrors[d].rdev);
 						if (rdev &&
 						    test_bit(In_sync, &rdev->flags)) {
+							atomic_inc(&rdev->nr_pending);
+							rcu_read_unlock();
 							atomic_add(s, &rdev->corrected_errors);
 							if (sync_page_io(rdev->bdev,
 									 r10_bio->devs[sl].addr +
@@ -1444,6 +1453,8 @@ static void raid10d(mddev_t *mddev)
 									 s<<9, conf->tmppage, WRITE) == 0)
 								/* Well, this device is dead */
 								md_error(mddev, rdev);
+							rdev_dec_pending(rdev, mddev);
+							rcu_read_lock();
 						}
 					}
 					sl = start;
@@ -1453,17 +1464,22 @@ static void raid10d(mddev_t *mddev)
 							sl = conf->copies;
 						sl--;
 						d = r10_bio->devs[sl].devnum;
-						rdev = conf->mirrors[d].rdev;
+						rdev = rcu_dereference(conf->mirrors[d].rdev);
 						if (rdev &&
 						    test_bit(In_sync, &rdev->flags)) {
+							atomic_inc(&rdev->nr_pending);
+							rcu_read_unlock();
 							if (sync_page_io(rdev->bdev,
 									 r10_bio->devs[sl].addr +
 									 sect + rdev->data_offset,
 									 s<<9, conf->tmppage, READ) == 0)
 								/* Well, this device is dead */
 								md_error(mddev, rdev);
+							rdev_dec_pending(rdev, mddev);
+							rcu_read_lock();
 						}
 					}
+					rcu_read_unlock();
 				} else {
 					/* Cannot read from anywhere -- bye bye array */
 					md_error(mddev, conf->mirrors[r10_bio->devs[r10_bio->read_slot].devnum].rdev);