md: raid1/raid10: handle allocation errors during array setup.

Both raid1 and raid10 create a mempool during startup.
If the 'alloc' function for this mempool fails, unplug_slaves
is called.
If that happens when the pool is being initialised, unplug_slaves
will try to use the 'conf' structure that isn't filled in yet, and
badness will happen.

So ensure that unplug_slaves doesn't get called unless we know
that the conf structure if fully initialised.

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

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 71a01a2e1938..a053423785c9 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -64,7 +64,7 @@ static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
 
         /* allocate a r1bio with room for raid_disks entries in the bios array */
         r1_bio = kzalloc(size, gfp_flags);
-        if (!r1_bio)
+        if (!r1_bio && pi->mddev)
                 unplug_slaves(pi->mddev);
 
         return r1_bio;
@@ -1979,13 +1979,14 @@ static int run(mddev_t *mddev)
         conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
         if (!conf->poolinfo)
                 goto out_no_mem;
-        conf->poolinfo->mddev = mddev;
+        conf->poolinfo->mddev = NULL;
         conf->poolinfo->raid_disks = mddev->raid_disks;
         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
                                           r1bio_pool_free,
                                           conf->poolinfo);
         if (!conf->r1bio_pool)
                 goto out_no_mem;
+        conf->poolinfo->mddev = mddev;
 
         spin_lock_init(&conf->device_lock);
         mddev->queue->queue_lock = &conf->device_lock;