Merge tag 'v3.5'

Linux 3.5

* tag 'v3.5': (1242 commits)
  Linux 3.5
  Remove SYSTEM_SUSPEND_DISK system state
  kdb: Switch to nolock variants of kmsg_dump functions
  printk: Implement some unlocked kmsg_dump functions
  printk: Remove kdb_syslog_data
  kdb: Revive dmesg command
  dm raid1: set discard_zeroes_data_unsupported
  dm thin: do not send discards to shared blocks
  dm raid1: fix crash with mirror recovery and discard
  pnfs-obj: Fix __r4w_get_page when offset is beyond i_size
  pnfs-obj: don't leak objio_state if ore_write/read fails
  ore: Unlock r4w pages in exact reverse order of locking
  ore: Remove support of partial IO request (NFS crash)
  ore: Fix NFS crash by supporting any unaligned RAID IO
  UBIFS: fix a bug in empty space fix-up
  cx25821: Remove bad strcpy to read-only char*
  HID: hid-multitouch: add support for Zytronic panels
  MIPS: PCI: Move fixups from __init to __devinit.
  MIPS: Fix bug.h MIPS build regression
  MIPS: sync-r4k: remove redundant irq operation
  ...

1 files changed, 51 insertions, 6 deletions

diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index 75506ec..f56c8ba 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -188,6 +188,26 @@ static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
 					rpdev->id.name);
 }
 
+/**
+ * __ept_release() - deallocate an rpmsg endpoint
+ * @kref: the ept's reference count
+ *
+ * This function deallocates an ept, and is invoked when its @kref refcount
+ * drops to zero.
+ *
+ * Never invoke this function directly!
+ */
+static void __ept_release(struct kref *kref)
+{
+	struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint,
+						  refcount);
+	/*
+	 * At this point no one holds a reference to ept anymore,
+	 * so we can directly free it
+	 */
+	kfree(ept);
+}
+
 /* for more info, see below documentation of rpmsg_create_ept() */
 static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
 		struct rpmsg_channel *rpdev, rpmsg_rx_cb_t cb,
@@ -206,6 +226,9 @@ static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
 		return NULL;
 	}
 
+	kref_init(&ept->refcount);
+	mutex_init(&ept->cb_lock);
+
 	ept->rpdev = rpdev;
 	ept->cb = cb;
 	ept->priv = priv;
@@ -238,7 +261,7 @@ rem_idr:
 	idr_remove(&vrp->endpoints, request);
 free_ept:
 	mutex_unlock(&vrp->endpoints_lock);
-	kfree(ept);
+	kref_put(&ept->refcount, __ept_release);
 	return NULL;
 }
 
@@ -302,11 +325,17 @@ EXPORT_SYMBOL(rpmsg_create_ept);
 static void
 __rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept)
 {
+	/* make sure new inbound messages can't find this ept anymore */
 	mutex_lock(&vrp->endpoints_lock);
 	idr_remove(&vrp->endpoints, ept->addr);
 	mutex_unlock(&vrp->endpoints_lock);
 
-	kfree(ept);
+	/* make sure in-flight inbound messages won't invoke cb anymore */
+	mutex_lock(&ept->cb_lock);
+	ept->cb = NULL;
+	mutex_unlock(&ept->cb_lock);
+
+	kref_put(&ept->refcount, __ept_release);
 }
 
 /**
@@ -790,12 +819,28 @@ static void rpmsg_recv_done(struct virtqueue *rvq)
 
 	/* use the dst addr to fetch the callback of the appropriate user */
 	mutex_lock(&vrp->endpoints_lock);
+
 	ept = idr_find(&vrp->endpoints, msg->dst);
+
+	/* let's make sure no one deallocates ept while we use it */
+	if (ept)
+		kref_get(&ept->refcount);
+
 	mutex_unlock(&vrp->endpoints_lock);
 
-	if (ept && ept->cb)
-		ept->cb(ept->rpdev, msg->data, msg->len, ept->priv, msg->src);
-	else
+	if (ept) {
+		/* make sure ept->cb doesn't go away while we use it */
+		mutex_lock(&ept->cb_lock);
+
+		if (ept->cb)
+			ept->cb(ept->rpdev, msg->data, msg->len, ept->priv,
+				msg->src);
+
+		mutex_unlock(&ept->cb_lock);
+
+		/* farewell, ept, we don't need you anymore */
+		kref_put(&ept->refcount, __ept_release);
+	} else
 		dev_warn(dev, "msg received with no recepient\n");
 
 	/* publish the real size of the buffer */
@@ -1040,7 +1085,7 @@ static int __init rpmsg_init(void)
 
 	return ret;
 }
-module_init(rpmsg_init);
+subsys_initcall(rpmsg_init);
 
 static void __exit rpmsg_fini(void)
 {