Merge tag 'v3.10.93' of git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable into linux-linaro-lsk-v3.10

This is the 3.10.93 stable release

# gpg: Signature made Mon Nov  9 10:13:39 2015 PST using RSA key ID 6092693E
# gpg: Good signature from "Greg Kroah-Hartman (Linux kernel stable release signing key) <greg@kroah.com>"

* tag 'v3.10.93' of git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable: (24 commits)
  Linux 3.10.93
  xen: fix backport of previous kexec patch
  IB/cm: Fix rb-tree duplicate free and use-after-free
  mvsas: Fix NULL pointer dereference in mvs_slot_task_free
  md/raid10: submit_bio_wait() returns 0 on success
  md/raid1: submit_bio_wait() returns 0 on success
  crypto: api - Only abort operations on fatal signal
  module: Fix locking in symbol_put_addr()
  xen-blkfront: check for null drvdata in blkback_changed (XenbusStateClosing)
  xhci: handle no ping response error properly
  dm btree: fix leak of bufio-backed block in btree_split_beneath error path
  dm btree remove: fix a bug when rebalancing nodes after removal
  Revert "ARM64: unwind: Fix PC calculation"
  rbd: prevent kernel stack blow up on rbd map
  rbd: don't leak parent_spec in rbd_dev_probe_parent()
  rbd: require stable pages if message data CRCs are enabled
  drm/nouveau/gem: return only valid domain when there's only one
  mm: make sendfile(2) killable
  ASoC: wm8904: Correct number of EQ registers
  powerpc/rtas: Validate rtas.entry before calling enter_rtas()
  ...

2 files changed, 41 insertions, 29 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 2fa22c24fa5d..85b31ba9d503 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -93,6 +93,8 @@ static int atomic_dec_return_safe(atomic_t *v)
 
 #define RBD_MINORS_PER_MAJOR	256		/* max minors per blkdev */
 
+#define RBD_MAX_PARENT_CHAIN_LEN	16
+
 #define RBD_SNAP_DEV_NAME_PREFIX	"snap_"
 #define RBD_MAX_SNAP_NAME_LEN	\
 			(NAME_MAX - (sizeof (RBD_SNAP_DEV_NAME_PREFIX) - 1))
@@ -394,7 +396,7 @@ static ssize_t rbd_add(struct bus_type *bus, const char *buf,
 		       size_t count);
 static ssize_t rbd_remove(struct bus_type *bus, const char *buf,
 			  size_t count);
-static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping);
+static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth);
 static void rbd_spec_put(struct rbd_spec *spec);
 
 static struct bus_attribute rbd_bus_attrs[] = {
@@ -3453,6 +3455,9 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
 	blk_queue_io_opt(q, segment_size);
 
 	blk_queue_merge_bvec(q, rbd_merge_bvec);
+	if (!ceph_test_opt(rbd_dev->rbd_client->client, NOCRC))
+		q->backing_dev_info.capabilities |= BDI_CAP_STABLE_WRITES;
+
 	disk->queue = q;
 
 	q->queuedata = rbd_dev;
@@ -4828,44 +4833,50 @@ out_err:
 	return ret;
 }
 
-static int rbd_dev_probe_parent(struct rbd_device *rbd_dev)
+/*
+ * @depth is rbd_dev_image_probe() -> rbd_dev_probe_parent() ->
+ * rbd_dev_image_probe() recursion depth, which means it's also the
+ * length of the already discovered part of the parent chain.
+ */
+static int rbd_dev_probe_parent(struct rbd_device *rbd_dev, int depth)
 {
 	struct rbd_device *parent = NULL;
-	struct rbd_spec *parent_spec;
-	struct rbd_client *rbdc;
 	int ret;
 
 	if (!rbd_dev->parent_spec)
 		return 0;
-	/*
-	 * We need to pass a reference to the client and the parent
-	 * spec when creating the parent rbd_dev.  Images related by
-	 * parent/child relationships always share both.
-	 */
-	parent_spec = rbd_spec_get(rbd_dev->parent_spec);
-	rbdc = __rbd_get_client(rbd_dev->rbd_client);
 
-	ret = -ENOMEM;
-	parent = rbd_dev_create(rbdc, parent_spec);
-	if (!parent)
+	if (++depth > RBD_MAX_PARENT_CHAIN_LEN) {
+		pr_info("parent chain is too long (%d)\n", depth);
+		ret = -EINVAL;
 		goto out_err;
+	}
 
-	ret = rbd_dev_image_probe(parent, false);
+	parent = rbd_dev_create(rbd_dev->rbd_client, rbd_dev->parent_spec);
+	if (!parent) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+
+	/*
+	 * Images related by parent/child relationships always share
+	 * rbd_client and spec/parent_spec, so bump their refcounts.
+	 */
+	__rbd_get_client(rbd_dev->rbd_client);
+	rbd_spec_get(rbd_dev->parent_spec);
+
+	ret = rbd_dev_image_probe(parent, depth);
 	if (ret < 0)
 		goto out_err;
+
 	rbd_dev->parent = parent;
 	atomic_set(&rbd_dev->parent_ref, 1);
-
 	return 0;
+
 out_err:
-	if (parent) {
-		rbd_dev_unparent(rbd_dev);
+	rbd_dev_unparent(rbd_dev);
+	if (parent)
 		rbd_dev_destroy(parent);
-	} else {
-		rbd_put_client(rbdc);
-		rbd_spec_put(parent_spec);
-	}
-
 	return ret;
 }
 
@@ -4971,7 +4982,7 @@ static void rbd_dev_image_release(struct rbd_device *rbd_dev)
  * parent), initiate a watch on its header object before using that
  * object to get detailed information about the rbd image.
  */
-static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping)
+static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth)
 {
 	int ret;
 	int tmp;
@@ -4992,7 +5003,7 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping)
 	if (ret)
 		goto err_out_format;
 
-	if (mapping) {
+	if (!depth) {
 		ret = rbd_dev_header_watch_sync(rbd_dev, true);
 		if (ret)
 			goto out_header_name;
@@ -5009,7 +5020,7 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping)
 	if (ret)
 		goto err_out_probe;
 
-	ret = rbd_dev_probe_parent(rbd_dev);
+	ret = rbd_dev_probe_parent(rbd_dev, depth);
 	if (ret)
 		goto err_out_probe;
 
@@ -5020,7 +5031,7 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping)
 err_out_probe:
 	rbd_dev_unprobe(rbd_dev);
 err_out_watch:
-	if (mapping) {
+	if (!depth) {
 		tmp = rbd_dev_header_watch_sync(rbd_dev, false);
 		if (tmp)
 			rbd_warn(rbd_dev, "unable to tear down "
@@ -5091,7 +5102,7 @@ static ssize_t rbd_add(struct bus_type *bus,
 	rbdc = NULL;		/* rbd_dev now owns this */
 	spec = NULL;		/* rbd_dev now owns this */
 
-	rc = rbd_dev_image_probe(rbd_dev, true);
+	rc = rbd_dev_image_probe(rbd_dev, 0);
 	if (rc < 0)
 		goto err_out_rbd_dev;
 
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index ddd9a098bc67..ea7ed8600a7c 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1590,7 +1590,8 @@ static void blkback_changed(struct xenbus_device *dev,
 			break;
 		/* Missed the backend's Closing state -- fallthrough */
 	case XenbusStateClosing:
-		blkfront_closing(info);
+		if (info)
+			blkfront_closing(info);
 		break;
 	}
 }