1 files changed, 24 insertions, 14 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index de5ed6fd8806..0138a727c1f3 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -659,7 +659,11 @@ static int raid10_mergeable_bvec(struct request_queue *q,
                 max = biovec->bv_len;
 
         if (mddev->merge_check_needed) {
-                struct r10bio r10_bio;
+                struct {
+                        struct r10bio r10_bio;
+                        struct r10dev devs[conf->copies];
+                } on_stack;
+                struct r10bio *r10_bio = &on_stack.r10_bio;
                 int s;
                 if (conf->reshape_progress != MaxSector) {
                         /* Cannot give any guidance during reshape */
@@ -667,18 +671,18 @@ static int raid10_mergeable_bvec(struct request_queue *q,
                                 return biovec->bv_len;
                         return 0;
                 }
-                r10_bio.sector = sector;
-                raid10_find_phys(conf, &r10_bio);
+                r10_bio->sector = sector;
+                raid10_find_phys(conf, r10_bio);
                 rcu_read_lock();
                 for (s = 0; s < conf->copies; s++) {
-                        int disk = r10_bio.devs[s].devnum;
+                        int disk = r10_bio->devs[s].devnum;
                         struct md_rdev *rdev = rcu_dereference(
                                 conf->mirrors[disk].rdev);
                         if (rdev && !test_bit(Faulty, &rdev->flags)) {
                                 struct request_queue *q =
                                         bdev_get_queue(rdev->bdev);
                                 if (q->merge_bvec_fn) {
-                                        bvm->bi_sector = r10_bio.devs[s].addr
+                                        bvm->bi_sector = r10_bio->devs[s].addr
                                                 + rdev->data_offset;
                                         bvm->bi_bdev = rdev->bdev;
                                         max = min(max, q->merge_bvec_fn(
@@ -690,7 +694,7 @@ static int raid10_mergeable_bvec(struct request_queue *q,
                                 struct request_queue *q =
                                         bdev_get_queue(rdev->bdev);
                                 if (q->merge_bvec_fn) {
-                                        bvm->bi_sector = r10_bio.devs[s].addr
+                                        bvm->bi_sector = r10_bio->devs[s].addr
                                                 + rdev->data_offset;
                                         bvm->bi_bdev = rdev->bdev;
                                         max = min(max, q->merge_bvec_fn(
@@ -1508,14 +1512,16 @@ static int _enough(struct r10conf *conf, struct geom *geo, int ignore)
         do {
                 int n = conf->copies;
                 int cnt = 0;
+                int this = first;
                 while (n--) {
-                        if (conf->mirrors[first].rdev &&
-                            first != ignore)
+                        if (conf->mirrors[this].rdev &&
+                            this != ignore)
                                 cnt++;
-                        first = (first+1) % geo->raid_disks;
+                        this = (this+1) % geo->raid_disks;
                 }
                 if (cnt == 0)
                         return 0;
+                first = (first + geo->near_copies) % geo->raid_disks;
         } while (first != 0);
         return 1;
 }
@@ -4414,14 +4420,18 @@ static int handle_reshape_read_error(struct mddev *mddev,
 {
         /* Use sync reads to get the blocks from somewhere else */
         int sectors = r10_bio->sectors;
-        struct r10bio r10b;
         struct r10conf *conf = mddev->private;
+        struct {
+                struct r10bio r10_bio;
+                struct r10dev devs[conf->copies];
+        } on_stack;
+        struct r10bio *r10b = &on_stack.r10_bio;
         int slot = 0;
         int idx = 0;
         struct bio_vec *bvec = r10_bio->master_bio->bi_io_vec;
 
-        r10b.sector = r10_bio->sector;
-        __raid10_find_phys(&conf->prev, &r10b);
+        r10b->sector = r10_bio->sector;
+        __raid10_find_phys(&conf->prev, r10b);
 
         while (sectors) {
                 int s = sectors;
@@ -4432,7 +4442,7 @@ static int handle_reshape_read_error(struct mddev *mddev,
                         s = PAGE_SIZE >> 9;
 
                 while (!success) {
-                        int d = r10b.devs[slot].devnum;
+                        int d = r10b->devs[slot].devnum;
                         struct md_rdev *rdev = conf->mirrors[d].rdev;
                         sector_t addr;
                         if (rdev == NULL ||
@@ -4440,7 +4450,7 @@ static int handle_reshape_read_error(struct mddev *mddev,
                             !test_bit(In_sync, &rdev->flags))
                                 goto failed;
 
-                        addr = r10b.devs[slot].addr + idx * PAGE_SIZE;
+                        addr = r10b->devs[slot].addr + idx * PAGE_SIZE;
                         success = sync_page_io(rdev,
                                                addr,
                                                s << 9,