[3.8.y.z extended stable] Patch "dm thin: initialize dm_thin_new_mapping returned by get_next_mapping" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    dm thin: initialize dm_thin_new_mapping returned by get_next_mapping

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.18.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 22bd8acdc0ed2dce4dd9372d69aae0fde9622b03 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer at redhat.com>
Date: Tue, 17 Dec 2013 13:19:11 -0500
Subject: dm thin: initialize dm_thin_new_mapping returned by get_next_mapping

commit 16961b042db8cc5cf75d782b4255193ad56e1d4f upstream.

As additional members are added to the dm_thin_new_mapping structure
care should be taken to make sure they get initialized before use.

Signed-off-by: Mike Snitzer <snitzer at redhat.com>
Acked-by: Joe Thornber <ejt at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/md/dm-thin.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 44a715f..b6fdaf7 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -678,13 +678,17 @@ static int ensure_next_mapping(struct pool *pool)

 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
 {
-	struct dm_thin_new_mapping *r = pool->next_mapping;
+	struct dm_thin_new_mapping *m = pool->next_mapping;

 	BUG_ON(!pool->next_mapping);

+	memset(m, 0, sizeof(struct dm_thin_new_mapping));
+	INIT_LIST_HEAD(&m->list);
+	m->bio = NULL;
+
 	pool->next_mapping = NULL;

-	return r;
+	return m;
 }

 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
@@ -696,15 +700,10 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
 	struct pool *pool = tc->pool;
 	struct dm_thin_new_mapping *m = get_next_mapping(pool);

-	INIT_LIST_HEAD(&m->list);
-	m->quiesced = 0;
-	m->prepared = 0;
 	m->tc = tc;
 	m->virt_block = virt_block;
 	m->data_block = data_dest;
 	m->cell = cell;
-	m->err = 0;
-	m->bio = NULL;

 	if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
 		m->quiesced = 1;
@@ -767,15 +766,12 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
 	struct pool *pool = tc->pool;
 	struct dm_thin_new_mapping *m = get_next_mapping(pool);

-	INIT_LIST_HEAD(&m->list);
 	m->quiesced = 1;
 	m->prepared = 0;
 	m->tc = tc;
 	m->virt_block = virt_block;
 	m->data_block = data_block;
 	m->cell = cell;
-	m->err = 0;
-	m->bio = NULL;

 	/*
 	 * If the whole block of data is being overwritten or we are not
@@ -966,7 +962,6 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
 			m->data_block = lookup_result.block;
 			m->cell = cell;
 			m->cell2 = cell2;
-			m->err = 0;
 			m->bio = bio;

 			if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
--
1.8.3.2