From 14f398ca2f26a2ed6236aec54395e0fa06ec8a82 Mon Sep 17 00:00:00 2001
From: Heinz Mauelshagen <heinzm@redhat.com>
Date: Fri, 28 Feb 2014 12:02:56 -0500
Subject: dm cache mq: fix memory allocation failure for large cache devices

The memory allocated for the multiqueue policy's hash table doesn't need
to be physically contiguous.  Use vzalloc() instead of kzalloc().
Fedora has been carrying this fix since 10/10/2013.

Failure seen during creation of a 10TB cached device with a 2048 sector
block size and 411GB cache size:

 dmsetup: page allocation failure: order:9, mode:0x10c0d0
 CPU: 11 PID: 29235 Comm: dmsetup Not tainted 3.10.4 #3
 Hardware name: Supermicro X8DTL/X8DTL, BIOS 2.1a       12/30/2011
  000000000010c0d0 ffff880090941898 ffffffff81387ab4 ffff880090941928
  ffffffff810bb26f 0000000000000009 000000000010c0d0 ffff880090941928
  ffffffff81385dbc ffffffff815f3840 ffffffff00000000 000002000010c0d0
 Call Trace:
  [<ffffffff81387ab4>] dump_stack+0x19/0x1b
  [<ffffffff810bb26f>] warn_alloc_failed+0x110/0x124
  [<ffffffff81385dbc>] ? __alloc_pages_direct_compact+0x17c/0x18e
  [<ffffffff810bda2e>] __alloc_pages_nodemask+0x6c7/0x75e
  [<ffffffff810bdad7>] __get_free_pages+0x12/0x3f
  [<ffffffff810ea148>] kmalloc_order_trace+0x29/0x88
  [<ffffffff810ec1fd>] __kmalloc+0x36/0x11b
  [<ffffffffa031eeed>] ? mq_create+0x1dc/0x2cf [dm_cache_mq]
  [<ffffffffa031efc0>] mq_create+0x2af/0x2cf [dm_cache_mq]
  [<ffffffffa0314605>] dm_cache_policy_create+0xa7/0xd2 [dm_cache]
  [<ffffffffa0312530>] ? cache_ctr+0x245/0xa13 [dm_cache]
  [<ffffffffa031263e>] cache_ctr+0x353/0xa13 [dm_cache]
  [<ffffffffa012b916>] dm_table_add_target+0x227/0x2ce [dm_mod]
  [<ffffffffa012e8e4>] table_load+0x286/0x2ac [dm_mod]
  [<ffffffffa012e65e>] ? dev_wait+0x8a/0x8a [dm_mod]
  [<ffffffffa012e324>] ctl_ioctl+0x39a/0x3c2 [dm_mod]
  [<ffffffffa012e35a>] dm_ctl_ioctl+0xe/0x12 [dm_mod]
  [<ffffffff81101181>] vfs_ioctl+0x21/0x34
  [<ffffffff811019d3>] do_vfs_ioctl+0x3b1/0x3f4
  [<ffffffff810f4d2e>] ? ____fput+0x9/0xb
  [<ffffffff81050b6c>] ? task_work_run+0x7e/0x92
  [<ffffffff81101a68>] SyS_ioctl+0x52/0x82
  [<ffffffff81391d92>] system_call_fastpath+0x16/0x1b

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/md/dm-cache-policy-mq.c b/drivers/md/dm-cache-policy-mq.c
index 1e018e9..0e385e4 100644
--- a/drivers/md/dm-cache-policy-mq.c
+++ b/drivers/md/dm-cache-policy-mq.c
@@ -872,7 +872,7 @@ static void mq_destroy(struct dm_cache_policy *p)
 {
 	struct mq_policy *mq = to_mq_policy(p);
 
-	kfree(mq->table);
+	vfree(mq->table);
 	epool_exit(&mq->cache_pool);
 	epool_exit(&mq->pre_cache_pool);
 	kfree(mq);
@@ -1245,7 +1245,7 @@ static struct dm_cache_policy *mq_create(dm_cblock_t cache_size,
 
 	mq->nr_buckets = next_power(from_cblock(cache_size) / 2, 16);
 	mq->hash_bits = ffs(mq->nr_buckets) - 1;
-	mq->table = kzalloc(sizeof(*mq->table) * mq->nr_buckets, GFP_KERNEL);
+	mq->table = vzalloc(sizeof(*mq->table) * mq->nr_buckets);
 	if (!mq->table)
 		goto bad_alloc_table;
 
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