[PATCH] md: provide proper rcu_dereference / rcu_assign_pointer annotations in md

Acked-by: <paulmck@us.ibm.com>
Signed-off-by: Suzanne Wood <suzannew@cs.pdx.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

5 files changed, 38 insertions, 36 deletions

diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index c06f4474192b..ae2c5fd6105d 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -63,7 +63,7 @@ static int multipath_map (multipath_conf_t *conf)
 
         rcu_read_lock();
         for (i = 0; i < disks; i++) {
-                mdk_rdev_t *rdev = conf->multipaths[i].rdev;
+                mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev);
                 if (rdev && rdev->in_sync) {
                         atomic_inc(&rdev->nr_pending);
                         rcu_read_unlock();
@@ -139,7 +139,7 @@ static void unplug_slaves(mddev_t *mddev)
 
         rcu_read_lock();
         for (i=0; i<mddev->raid_disks; i++) {
-                mdk_rdev_t *rdev = conf->multipaths[i].rdev;
+                mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev);
                 if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) {
                         request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
 
@@ -224,7 +224,7 @@ static int multipath_issue_flush(request_queue_t *q, struct gendisk *disk,
 
         rcu_read_lock();
         for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-                mdk_rdev_t *rdev = conf->multipaths[i].rdev;
+                mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev);
                 if (rdev && !rdev->faulty) {
                         struct block_device *bdev = rdev->bdev;
                         request_queue_t *r_queue = bdev_get_queue(bdev);
@@ -331,7 +331,7 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                         conf->working_disks++;
                         rdev->raid_disk = path;
                         rdev->in_sync = 1;
-                        p->rdev = rdev;
+                        rcu_assign_pointer(p->rdev, rdev);
                         found = 1;
                 }
 
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index e16f473bcf46..f12fc288f25d 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -416,10 +416,10 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio)
                 /* Choose the first operation device, for consistancy */
                 new_disk = 0;
 
-                for (rdev = conf->mirrors[new_disk].rdev;
+                for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
                      !rdev || !rdev->in_sync
                              || test_bit(WriteMostly, &rdev->flags);
-                     rdev = conf->mirrors[++new_disk].rdev) {
+                     rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
 
                         if (rdev && rdev->in_sync)
                                 wonly_disk = new_disk;
@@ -434,10 +434,10 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio)
 
 
         /* make sure the disk is operational */
-        for (rdev = conf->mirrors[new_disk].rdev;
+        for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
              !rdev || !rdev->in_sync ||
                      test_bit(WriteMostly, &rdev->flags);
-             rdev = conf->mirrors[new_disk].rdev) {
+             rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {
 
                 if (rdev && rdev->in_sync)
                         wonly_disk = new_disk;
@@ -474,7 +474,7 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio)
                         disk = conf->raid_disks;
                 disk--;
 
-                rdev = conf->mirrors[disk].rdev;
+                rdev = rcu_dereference(conf->mirrors[disk].rdev);
 
                 if (!rdev ||
                     !rdev->in_sync ||
@@ -496,7 +496,7 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio)
 
 
         if (new_disk >= 0) {
-                rdev = conf->mirrors[new_disk].rdev;
+                rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
                 if (!rdev)
                         goto retry;
                 atomic_inc(&rdev->nr_pending);
@@ -522,7 +522,7 @@ static void unplug_slaves(mddev_t *mddev)
 
         rcu_read_lock();
         for (i=0; i<mddev->raid_disks; i++) {
-                mdk_rdev_t *rdev = conf->mirrors[i].rdev;
+                mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
                 if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) {
                         request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
 
@@ -556,7 +556,7 @@ static int raid1_issue_flush(request_queue_t *q, struct gendisk *disk,
 
         rcu_read_lock();
         for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-                mdk_rdev_t *rdev = conf->mirrors[i].rdev;
+                mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
                 if (rdev && !rdev->faulty) {
                         struct block_device *bdev = rdev->bdev;
                         request_queue_t *r_queue = bdev_get_queue(bdev);
@@ -728,7 +728,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
 #endif
         rcu_read_lock();
         for (i = 0;  i < disks; i++) {
-                if ((rdev=conf->mirrors[i].rdev) != NULL &&
+                if ((rdev=rcu_dereference(conf->mirrors[i].rdev)) != NULL &&
                     !rdev->faulty) {
                         atomic_inc(&rdev->nr_pending);
                         if (rdev->faulty) {
@@ -954,7 +954,7 @@ static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                         found = 1;
                         if (rdev->saved_raid_disk != mirror)
                                 conf->fullsync = 1;
-                        p->rdev = rdev;
+                        rcu_assign_pointer(p->rdev, rdev);
                         break;
                 }
 
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index bbe40e9cf923..26114f40bde6 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -496,6 +496,7 @@ static int read_balance(conf_t *conf, r10bio_t *r10_bio)
         int disk, slot, nslot;
         const int sectors = r10_bio->sectors;
         sector_t new_distance, current_distance;
+        mdk_rdev_t *rdev;
 
         raid10_find_phys(conf, r10_bio);
         rcu_read_lock();
@@ -510,8 +511,8 @@ static int read_balance(conf_t *conf, r10bio_t *r10_bio)
                 slot = 0;
                 disk = r10_bio->devs[slot].devnum;
 
-                while (!conf->mirrors[disk].rdev ||
-                       !conf->mirrors[disk].rdev->in_sync) {
+                while ((rdev = rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
+                       !rdev->in_sync) {
                         slot++;
                         if (slot == conf->copies) {
                                 slot = 0;
@@ -527,8 +528,8 @@ static int read_balance(conf_t *conf, r10bio_t *r10_bio)
         /* make sure the disk is operational */
         slot = 0;
         disk = r10_bio->devs[slot].devnum;
-        while (!conf->mirrors[disk].rdev ||
-               !conf->mirrors[disk].rdev->in_sync) {
+        while ((rdev=rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
+               !rdev->in_sync) {
                 slot ++;
                 if (slot == conf->copies) {
                         disk = -1;
@@ -547,11 +548,11 @@ static int read_balance(conf_t *conf, r10bio_t *r10_bio)
                 int ndisk = r10_bio->devs[nslot].devnum;
 
 
-                if (!conf->mirrors[ndisk].rdev ||
-                    !conf->mirrors[ndisk].rdev->in_sync)
+                if ((rdev=rcu_dereference(conf->mirrors[ndisk].rdev)) == NULL ||
+                    !rdev->in_sync)
                         continue;
 
-                if (!atomic_read(&conf->mirrors[ndisk].rdev->nr_pending)) {
+                if (!atomic_read(&rdev->nr_pending)) {
                         disk = ndisk;
                         slot = nslot;
                         break;
@@ -569,7 +570,7 @@ rb_out:
         r10_bio->read_slot = slot;
 /*      conf->next_seq_sect = this_sector + sectors;*/
 
-        if (disk >= 0 && conf->mirrors[disk].rdev)
+        if (disk >= 0 && (rdev=rcu_dereference(conf->mirrors[disk].rdev))!= NULL)
                 atomic_inc(&conf->mirrors[disk].rdev->nr_pending);
         rcu_read_unlock();
 
@@ -583,7 +584,7 @@ static void unplug_slaves(mddev_t *mddev)
 
         rcu_read_lock();
         for (i=0; i<mddev->raid_disks; i++) {
-                mdk_rdev_t *rdev = conf->mirrors[i].rdev;
+                mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
                 if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) {
                         request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
 
@@ -614,7 +615,7 @@ static int raid10_issue_flush(request_queue_t *q, struct gendisk *disk,
 
         rcu_read_lock();
         for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-                mdk_rdev_t *rdev = conf->mirrors[i].rdev;
+                mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
                 if (rdev && !rdev->faulty) {
                         struct block_device *bdev = rdev->bdev;
                         request_queue_t *r_queue = bdev_get_queue(bdev);
@@ -768,9 +769,10 @@ static int make_request(request_queue_t *q, struct bio * bio)
         rcu_read_lock();
         for (i = 0;  i < conf->copies; i++) {
                 int d = r10_bio->devs[i].devnum;
-                if (conf->mirrors[d].rdev &&
-                    !conf->mirrors[d].rdev->faulty) {
-                        atomic_inc(&conf->mirrors[d].rdev->nr_pending);
+                mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev);
+                if (rdev &&
+                    !rdev->faulty) {
+                        atomic_inc(&rdev->nr_pending);
                         r10_bio->devs[i].bio = bio;
                 } else
                         r10_bio->devs[i].bio = NULL;
@@ -980,7 +982,7 @@ static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                         p->head_position = 0;
                         rdev->raid_disk = mirror;
                         found = 1;
-                        p->rdev = rdev;
+                        rcu_assign_pointer(p->rdev, rdev);
                         break;
                 }
 
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ce154553aca5..061d265ed94e 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1374,7 +1374,7 @@ static void handle_stripe(struct stripe_head *sh)
                         bi->bi_end_io = raid5_end_read_request;
  
                 rcu_read_lock();
-                rdev = conf->disks[i].rdev;
+                rdev = rcu_dereference(conf->disks[i].rdev);
                 if (rdev && rdev->faulty)
                         rdev = NULL;
                 if (rdev)
@@ -1448,7 +1448,7 @@ static void unplug_slaves(mddev_t *mddev)
 
         rcu_read_lock();
         for (i=0; i<mddev->raid_disks; i++) {
-                mdk_rdev_t *rdev = conf->disks[i].rdev;
+                mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
                 if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) {
                         request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
 
@@ -1493,7 +1493,7 @@ static int raid5_issue_flush(request_queue_t *q, struct gendisk *disk,
 
         rcu_read_lock();
         for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-                mdk_rdev_t *rdev = conf->disks[i].rdev;
+                mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
                 if (rdev && !rdev->faulty) {
                         struct block_device *bdev = rdev->bdev;
                         request_queue_t *r_queue = bdev_get_queue(bdev);
@@ -2165,7 +2165,7 @@ static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                         found = 1;
                         if (rdev->saved_raid_disk != disk)
                                 conf->fullsync = 1;
-                        p->rdev = rdev;
+                        rcu_assign_pointer(p->rdev, rdev);
                         break;
                 }
         print_raid5_conf(conf);
diff --git a/drivers/md/raid6main.c b/drivers/md/raid6main.c
index 775786947701..84f3ee01e4c8 100644
--- a/drivers/md/raid6main.c
+++ b/drivers/md/raid6main.c
@@ -1464,7 +1464,7 @@ static void handle_stripe(struct stripe_head *sh)
                         bi->bi_end_io = raid6_end_read_request;
 
                 rcu_read_lock();
-                rdev = conf->disks[i].rdev;
+                rdev = rcu_dereference(conf->disks[i].rdev);
                 if (rdev && rdev->faulty)
                         rdev = NULL;
                 if (rdev)
@@ -1538,7 +1538,7 @@ static void unplug_slaves(mddev_t *mddev)
 
         rcu_read_lock();
         for (i=0; i<mddev->raid_disks; i++) {
-                mdk_rdev_t *rdev = conf->disks[i].rdev;
+                mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
                 if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) {
                         request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
 
@@ -1583,7 +1583,7 @@ static int raid6_issue_flush(request_queue_t *q, struct gendisk *disk,
 
         rcu_read_lock();
         for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-                mdk_rdev_t *rdev = conf->disks[i].rdev;
+                mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
                 if (rdev && !rdev->faulty) {
                         struct block_device *bdev = rdev->bdev;
                         request_queue_t *r_queue = bdev_get_queue(bdev);
@@ -2154,7 +2154,7 @@ static int raid6_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                         found = 1;
                         if (rdev->saved_raid_disk != disk)
                                 conf->fullsync = 1;
-                        p->rdev = rdev;
+                        rcu_assign_pointer(p->rdev, rdev);
                         break;
                 }
         print_raid6_conf(conf);