Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio/vhost updates from Michael Tsirkin:
 "virtio, vhost: fixes, cleanups, features

  This includes the disk/cache memory stats for for the virtio balloon,
  as well as multiple fixes and cleanups"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost: don't hold onto file pointer for VHOST_SET_LOG_FD
  vhost: don't hold onto file pointer for VHOST_SET_VRING_ERR
  vhost: don't hold onto file pointer for VHOST_SET_VRING_CALL
  ringtest: ring.c malloc & memset to calloc
  virtio_vop: don't kfree device on register failure
  virtio_pci: don't kfree device on register failure
  virtio: split device_register into device_initialize and device_add
  vhost: remove unused lock check flag in vhost_dev_cleanup()
  vhost: Remove the unused variable.
  virtio_blk: print capacity at probe time
  virtio: make VIRTIO a menuconfig to ease disabling it all
  virtio/ringtest: virtio_ring: fix up need_event math
  virtio/ringtest: fix up need_event math
  virtio: virtio_mmio: make of_device_ids const.
  firmware: Use PTR_ERR_OR_ZERO()
  virtio-mmio: Use PTR_ERR_OR_ZERO()
  vhost/scsi: Improve a size determination in four functions
  virtio_balloon: include disk/file caches memory statistics

17 files changed, 120 insertions, 131 deletions

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 79908e6ddbf2..4a07593c2efd 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -373,14 +373,12 @@ static ssize_t virtblk_serial_show(struct device *dev,
 
 static DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
 
-static void virtblk_config_changed_work(struct work_struct *work)
+/* The queue's logical block size must be set before calling this */
+static void virtblk_update_capacity(struct virtio_blk *vblk, bool resize)
 {
-	struct virtio_blk *vblk =
-		container_of(work, struct virtio_blk, config_work);
 	struct virtio_device *vdev = vblk->vdev;
 	struct request_queue *q = vblk->disk->queue;
 	char cap_str_2[10], cap_str_10[10];
-	char *envp[] = { "RESIZE=1", NULL };
 	unsigned long long nblocks;
 	u64 capacity;
 
@@ -402,13 +400,24 @@ static void virtblk_config_changed_work(struct work_struct *work)
 			STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
 
 	dev_notice(&vdev->dev,
-		   "new size: %llu %d-byte logical blocks (%s/%s)\n",
+		   "[%s] %s%llu %d-byte logical blocks (%s/%s)\n",
+		   vblk->disk->disk_name,
+		   resize ? "new size: " : "",
 		   nblocks,
 		   queue_logical_block_size(q),
 		   cap_str_10,
 		   cap_str_2);
 
 	set_capacity(vblk->disk, capacity);
+}
+
+static void virtblk_config_changed_work(struct work_struct *work)
+{
+	struct virtio_blk *vblk =
+		container_of(work, struct virtio_blk, config_work);
+	char *envp[] = { "RESIZE=1", NULL };
+
+	virtblk_update_capacity(vblk, true);
 	revalidate_disk(vblk->disk);
 	kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp);
 }
@@ -621,7 +630,6 @@ static int virtblk_probe(struct virtio_device *vdev)
 	struct request_queue *q;
 	int err, index;
 
-	u64 cap;
 	u32 v, blk_size, sg_elems, opt_io_size;
 	u16 min_io_size;
 	u8 physical_block_exp, alignment_offset;
@@ -719,17 +727,6 @@ static int virtblk_probe(struct virtio_device *vdev)
 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
 		set_disk_ro(vblk->disk, 1);
 
-	/* Host must always specify the capacity. */
-	virtio_cread(vdev, struct virtio_blk_config, capacity, &cap);
-
-	/* If capacity is too big, truncate with warning. */
-	if ((sector_t)cap != cap) {
-		dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
-			 (unsigned long long)cap);
-		cap = (sector_t)-1;
-	}
-	set_capacity(vblk->disk, cap);
-
 	/* We can handle whatever the host told us to handle. */
 	blk_queue_max_segments(q, vblk->sg_elems-2);
 
@@ -780,6 +777,7 @@ static int virtblk_probe(struct virtio_device *vdev)
 	if (!err && opt_io_size)
 		blk_queue_io_opt(q, blk_size * opt_io_size);
 
+	virtblk_update_capacity(vblk, false);
 	virtio_device_ready(vdev);
 
 	device_add_disk(&vdev->dev, vblk->disk);
diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index deb483064f53..a41b572eeeb1 100644
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -694,10 +694,8 @@ static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
 	 */
 	fw_cfg_cmdline_dev = platform_device_register_simple("fw_cfg",
 					PLATFORM_DEVID_NONE, res, processed);
-	if (IS_ERR(fw_cfg_cmdline_dev))
-		return PTR_ERR(fw_cfg_cmdline_dev);
 
-	return 0;
+	return PTR_ERR_OR_ZERO(fw_cfg_cmdline_dev);
 }
 
 static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp)
diff --git a/drivers/misc/mic/vop/vop_main.c b/drivers/misc/mic/vop/vop_main.c
index a341938c7e2c..3633202e18f4 100644
--- a/drivers/misc/mic/vop/vop_main.c
+++ b/drivers/misc/mic/vop/vop_main.c
@@ -452,10 +452,12 @@ static irqreturn_t vop_virtio_intr_handler(int irq, void *data)
 
 static void vop_virtio_release_dev(struct device *_d)
 {
-	/*
-	 * No need for a release method similar to virtio PCI.
-	 * Provide an empty one to avoid getting a warning from core.
-	 */
+	struct virtio_device *vdev =
+			container_of(_d, struct virtio_device, dev);
+	struct _vop_vdev *vop_vdev =
+			container_of(vdev, struct _vop_vdev, vdev);
+
+	kfree(vop_vdev);
 }
 
 /*
@@ -466,7 +468,7 @@ static int _vop_add_device(struct mic_device_desc __iomem *d,
 			   unsigned int offset, struct vop_device *vpdev,
 			   int dnode)
 {
-	struct _vop_vdev *vdev;
+	struct _vop_vdev *vdev, *reg_dev = NULL;
 	int ret;
 	u8 type = ioread8(&d->type);
 
@@ -497,6 +499,7 @@ static int _vop_add_device(struct mic_device_desc __iomem *d,
 	vdev->c2h_vdev_db = ioread8(&vdev->dc->c2h_vdev_db);
 
 	ret = register_virtio_device(&vdev->vdev);
+	reg_dev = vdev;
 	if (ret) {
 		dev_err(_vop_dev(vdev),
 			"Failed to register vop device %u type %u\n",
@@ -512,7 +515,10 @@ static int _vop_add_device(struct mic_device_desc __iomem *d,
 free_irq:
 	vpdev->hw_ops->free_irq(vpdev, vdev->virtio_cookie, vdev);
 kfree:
-	kfree(vdev);
+	if (reg_dev)
+		put_device(&vdev->vdev.dev);
+	else
+		kfree(vdev);
 	return ret;
 }
 
@@ -568,7 +574,7 @@ static int _vop_remove_device(struct mic_device_desc __iomem *d,
 		iowrite8(-1, &dc->h2c_vdev_db);
 		if (status & VIRTIO_CONFIG_S_DRIVER_OK)
 			wait_for_completion(&vdev->reset_done);
-		kfree(vdev);
+		put_device(&vdev->vdev.dev);
 		iowrite8(1, &dc->guest_ack);
 		dev_dbg(&vpdev->dev, "%s %d guest_ack %d\n",
 			__func__, __LINE__, ioread8(&dc->guest_ack));
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 9c3f8160ef24..c613d2e3d371 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -1015,7 +1015,7 @@ static int vhost_net_release(struct inode *inode, struct file *f)
 	vhost_net_stop(n, &tx_sock, &rx_sock);
 	vhost_net_flush(n);
 	vhost_dev_stop(&n->dev);
-	vhost_dev_cleanup(&n->dev, false);
+	vhost_dev_cleanup(&n->dev);
 	vhost_net_vq_reset(n);
 	if (tx_sock)
 		sockfd_put(tx_sock);
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 71517b3c5558..7ad57094d736 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -586,8 +586,7 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg,
 	sg = cmd->tvc_sgl;
 	prot_sg = cmd->tvc_prot_sgl;
 	pages = cmd->tvc_upages;
-	memset(cmd, 0, sizeof(struct vhost_scsi_cmd));
-
+	memset(cmd, 0, sizeof(*cmd));
 	cmd->tvc_sgl = sg;
 	cmd->tvc_prot_sgl = prot_sg;
 	cmd->tvc_upages = pages;
@@ -1420,7 +1419,7 @@ static int vhost_scsi_release(struct inode *inode, struct file *f)
 	mutex_unlock(&vs->dev.mutex);
 	vhost_scsi_clear_endpoint(vs, &t);
 	vhost_dev_stop(&vs->dev);
-	vhost_dev_cleanup(&vs->dev, false);
+	vhost_dev_cleanup(&vs->dev);
 	/* Jobs can re-queue themselves in evt kick handler. Do extra flush. */
 	vhost_scsi_flush(vs);
 	kfree(vs->dev.vqs);
@@ -1725,7 +1724,7 @@ static int vhost_scsi_make_nexus(struct vhost_scsi_tpg *tpg,
 		return -EEXIST;
 	}
 
-	tv_nexus = kzalloc(sizeof(struct vhost_scsi_nexus), GFP_KERNEL);
+	tv_nexus = kzalloc(sizeof(*tv_nexus), GFP_KERNEL);
 	if (!tv_nexus) {
 		mutex_unlock(&tpg->tv_tpg_mutex);
 		pr_err("Unable to allocate struct vhost_scsi_nexus\n");
@@ -1926,7 +1925,7 @@ vhost_scsi_make_tpg(struct se_wwn *wwn,
 	if (kstrtou16(name + 5, 10, &tpgt) || tpgt >= VHOST_SCSI_MAX_TARGET)
 		return ERR_PTR(-EINVAL);
 
-	tpg = kzalloc(sizeof(struct vhost_scsi_tpg), GFP_KERNEL);
+	tpg = kzalloc(sizeof(*tpg), GFP_KERNEL);
 	if (!tpg) {
 		pr_err("Unable to allocate struct vhost_scsi_tpg");
 		return ERR_PTR(-ENOMEM);
@@ -1980,7 +1979,7 @@ vhost_scsi_make_tport(struct target_fabric_configfs *tf,
 	/* if (vhost_scsi_parse_wwn(name, &wwpn, 1) < 0)
 		return ERR_PTR(-EINVAL); */
 
-	tport = kzalloc(sizeof(struct vhost_scsi_tport), GFP_KERNEL);
+	tport = kzalloc(sizeof(*tport), GFP_KERNEL);
 	if (!tport) {
 		pr_err("Unable to allocate struct vhost_scsi_tport");
 		return ERR_PTR(-ENOMEM);
diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
index 3cc98c07dcd3..906b8f0f19f7 100644
--- a/drivers/vhost/test.c
+++ b/drivers/vhost/test.c
@@ -157,7 +157,7 @@ static int vhost_test_release(struct inode *inode, struct file *f)
 
 	vhost_test_stop(n, &private);
 	vhost_test_flush(n);
-	vhost_dev_cleanup(&n->dev, false);
+	vhost_dev_cleanup(&n->dev);
 	/* We do an extra flush before freeing memory,
 	 * since jobs can re-queue themselves. */
 	vhost_test_flush(n);
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 8d4374606756..2db5af8e8652 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -181,7 +181,6 @@ void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
 {
 	clear_bit(VHOST_WORK_QUEUED, &work->flags);
 	work->fn = fn;
-	init_waitqueue_head(&work->done);
 }
 EXPORT_SYMBOL_GPL(vhost_work_init);
 
@@ -319,10 +318,8 @@ static void vhost_vq_reset(struct vhost_dev *dev,
 	vq->acked_features = 0;
 	vq->log_base = NULL;
 	vq->error_ctx = NULL;
-	vq->error = NULL;
 	vq->kick = NULL;
 	vq->call_ctx = NULL;
-	vq->call = NULL;
 	vq->log_ctx = NULL;
 	vhost_reset_is_le(vq);
 	vhost_disable_cross_endian(vq);
@@ -422,7 +419,6 @@ void vhost_dev_init(struct vhost_dev *dev,
 	dev->nvqs = nvqs;
 	mutex_init(&dev->mutex);
 	dev->log_ctx = NULL;
-	dev->log_file = NULL;
 	dev->umem = NULL;
 	dev->iotlb = NULL;
 	dev->mm = NULL;
@@ -544,7 +540,7 @@ void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_umem *umem)
 {
 	int i;
 
-	vhost_dev_cleanup(dev, true);
+	vhost_dev_cleanup(dev);
 
 	/* Restore memory to default empty mapping. */
 	INIT_LIST_HEAD(&umem->umem_list);
@@ -611,31 +607,23 @@ static void vhost_clear_msg(struct vhost_dev *dev)
 	spin_unlock(&dev->iotlb_lock);
 }
 
-/* Caller should have device mutex if and only if locked is set */
-void vhost_dev_cleanup(struct vhost_dev *dev, bool locked)
+void vhost_dev_cleanup(struct vhost_dev *dev)
 {
 	int i;
 
 	for (i = 0; i < dev->nvqs; ++i) {
 		if (dev->vqs[i]->error_ctx)
 			eventfd_ctx_put(dev->vqs[i]->error_ctx);
-		if (dev->vqs[i]->error)
-			fput(dev->vqs[i]->error);
 		if (dev->vqs[i]->kick)
 			fput(dev->vqs[i]->kick);
 		if (dev->vqs[i]->call_ctx)
 			eventfd_ctx_put(dev->vqs[i]->call_ctx);
-		if (dev->vqs[i]->call)
-			fput(dev->vqs[i]->call);
 		vhost_vq_reset(dev, dev->vqs[i]);
 	}
 	vhost_dev_free_iovecs(dev);
 	if (dev->log_ctx)
 		eventfd_ctx_put(dev->log_ctx);
 	dev->log_ctx = NULL;
-	if (dev->log_file)
-		fput(dev->log_file);
-	dev->log_file = NULL;
 	/* No one will access memory at this point */
 	vhost_umem_clean(dev->umem);
 	dev->umem = NULL;
@@ -1492,38 +1480,24 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
 			r = -EFAULT;
 			break;
 		}
-		eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
-		if (IS_ERR(eventfp)) {
-			r = PTR_ERR(eventfp);
+		ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd);
+		if (IS_ERR(ctx)) {
+			r = PTR_ERR(ctx);
 			break;
 		}
-		if (eventfp != vq->call) {
-			filep = vq->call;
-			ctx = vq->call_ctx;
-			vq->call = eventfp;
-			vq->call_ctx = eventfp ?
-				eventfd_ctx_fileget(eventfp) : NULL;
-		} else
-			filep = eventfp;
+		swap(ctx, vq->call_ctx);
 		break;
 	case VHOST_SET_VRING_ERR:
 		if (copy_from_user(&f, argp, sizeof f)) {
 			r = -EFAULT;
 			break;
 		}
-		eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
-		if (IS_ERR(eventfp)) {
-			r = PTR_ERR(eventfp);
+		ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd);
+		if (IS_ERR(ctx)) {
+			r = PTR_ERR(ctx);
 			break;
 		}
-		if (eventfp != vq->error) {
-			filep = vq->error;
-			vq->error = eventfp;
-			ctx = vq->error_ctx;
-			vq->error_ctx = eventfp ?
-				eventfd_ctx_fileget(eventfp) : NULL;
-		} else
-			filep = eventfp;
+		swap(ctx, vq->error_ctx);
 		break;
 	case VHOST_SET_VRING_ENDIAN:
 		r = vhost_set_vring_endian(vq, argp);
@@ -1551,7 +1525,7 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
 	if (pollstop && vq->handle_kick)
 		vhost_poll_stop(&vq->poll);
 
-	if (ctx)
+	if (!IS_ERR_OR_NULL(ctx))
 		eventfd_ctx_put(ctx);
 	if (filep)
 		fput(filep);
@@ -1594,8 +1568,7 @@ EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
 /* Caller must have device mutex */
 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
 {
-	struct file *eventfp, *filep = NULL;
-	struct eventfd_ctx *ctx = NULL;
+	struct eventfd_ctx *ctx;
 	u64 p;
 	long r;
 	int i, fd;
@@ -1641,19 +1614,12 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
 		r = get_user(fd, (int __user *)argp);
 		if (r < 0)
 			break;
-		eventfp = fd == -1 ? NULL : eventfd_fget(fd);
-		if (IS_ERR(eventfp)) {
-			r = PTR_ERR(eventfp);
+		ctx = fd == -1 ? NULL : eventfd_ctx_fdget(fd);
+		if (IS_ERR(ctx)) {
+			r = PTR_ERR(ctx);
 			break;
 		}
-		if (eventfp != d->log_file) {
-			filep = d->log_file;
-			d->log_file = eventfp;
-			ctx = d->log_ctx;
-			d->log_ctx = eventfp ?
-				eventfd_ctx_fileget(eventfp) : NULL;
-		} else
-			filep = eventfp;
+		swap(ctx, d->log_ctx);
 		for (i = 0; i < d->nvqs; ++i) {
 			mutex_lock(&d->vqs[i]->mutex);
 			d->vqs[i]->log_ctx = d->log_ctx;
@@ -1661,8 +1627,6 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
 		}
 		if (ctx)
 			eventfd_ctx_put(ctx);
-		if (filep)
-			fput(filep);
 		break;
 	default:
 		r = -ENOIOCTLCMD;
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 7876a3d7d1b3..ac4b6056f19a 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -20,10 +20,6 @@ typedef void (*vhost_work_fn_t)(struct vhost_work *work);
 struct vhost_work {
 	struct llist_node	  node;
 	vhost_work_fn_t		  fn;
-	wait_queue_head_t	  done;
-	int			  flushing;
-	unsigned		  queue_seq;
-	unsigned		  done_seq;
 	unsigned long		  flags;
 };
 
@@ -96,8 +92,6 @@ struct vhost_virtqueue {
 	struct vring_used __user *used;
 	const struct vhost_umem_node *meta_iotlb[VHOST_NUM_ADDRS];
 	struct file *kick;
-	struct file *call;
-	struct file *error;
 	struct eventfd_ctx *call_ctx;
 	struct eventfd_ctx *error_ctx;
 	struct eventfd_ctx *log_ctx;
@@ -163,7 +157,6 @@ struct vhost_dev {
 	struct mutex mutex;
 	struct vhost_virtqueue **vqs;
 	int nvqs;
-	struct file *log_file;
 	struct eventfd_ctx *log_ctx;
 	struct llist_head work_list;
 	struct task_struct *worker;
@@ -181,7 +174,7 @@ bool vhost_dev_has_owner(struct vhost_dev *dev);
 long vhost_dev_check_owner(struct vhost_dev *);
 struct vhost_umem *vhost_dev_reset_owner_prepare(void);
 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_umem *);
-void vhost_dev_cleanup(struct vhost_dev *, bool locked);
+void vhost_dev_cleanup(struct vhost_dev *);
 void vhost_dev_stop(struct vhost_dev *);
 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 5a5e981bd8e4..0d14e2ff19f1 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -599,7 +599,7 @@ static int vhost_vsock_dev_release(struct inode *inode, struct file *file)
 	}
 	spin_unlock_bh(&vsock->send_pkt_list_lock);
 
-	vhost_dev_cleanup(&vsock->dev, false);
+	vhost_dev_cleanup(&vsock->dev);
 	kfree(vsock->dev.vqs);
 	vhost_vsock_free(vsock);
 	return 0;
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index cff773f15b7e..35897649c24f 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -5,7 +5,11 @@ config VIRTIO
 	  bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG
 	  or CONFIG_S390_GUEST.
 
-menu "Virtio drivers"
+menuconfig VIRTIO_MENU
+	bool "Virtio drivers"
+	default y
+
+if VIRTIO_MENU
 
 config VIRTIO_PCI
 	tristate "PCI driver for virtio devices"
@@ -79,4 +83,4 @@ config VIRTIO_MMIO_CMDLINE_DEVICES
 
 	 If unsure, say 'N'.
 
-endmenu
+endif # VIRTIO_MENU
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index bf7ff3934d7f..59e36ef4920f 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -303,11 +303,21 @@ void unregister_virtio_driver(struct virtio_driver *driver)
 }
 EXPORT_SYMBOL_GPL(unregister_virtio_driver);
 
+/**
+ * register_virtio_device - register virtio device
+ * @dev        : virtio device to be registered
+ *
+ * On error, the caller must call put_device on &@dev->dev (and not kfree),
+ * as another code path may have obtained a reference to @dev.
+ *
+ * Returns: 0 on suceess, -error on failure
+ */
 int register_virtio_device(struct virtio_device *dev)
 {
 	int err;
 
 	dev->dev.bus = &virtio_bus;
+	device_initialize(&dev->dev);
 
 	/* Assign a unique device index and hence name. */
 	err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
@@ -330,9 +340,11 @@ int register_virtio_device(struct virtio_device *dev)
 
 	INIT_LIST_HEAD(&dev->vqs);
 
-	/* device_register() causes the bus infrastructure to look for a
-	 * matching driver. */
-	err = device_register(&dev->dev);
+	/*
+	 * device_add() causes the bus infrastructure to look for a matching
+	 * driver.
+	 */
+	err = device_add(&dev->dev);
 	if (err)
 		ida_simple_remove(&virtio_index_ida, dev->index);
 out:
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index a1fb52cb3f0a..dfe5684000be 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -257,11 +257,13 @@ static unsigned int update_balloon_stats(struct virtio_balloon *vb)
 	struct sysinfo i;
 	unsigned int idx = 0;
 	long available;
+	unsigned long caches;
 
 	all_vm_events(events);
 	si_meminfo(&i);
 
 	available = si_mem_available();
+	caches = global_node_page_state(NR_FILE_PAGES);
 
 #ifdef CONFIG_VM_EVENT_COUNTERS
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN,
@@ -277,6 +279,8 @@ static unsigned int update_balloon_stats(struct virtio_balloon *vb)
 				pages_to_bytes(i.totalram));
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_AVAIL,
 				pages_to_bytes(available));
+	update_stat(vb, idx++, VIRTIO_BALLOON_S_CACHES,
+				pages_to_bytes(caches));
 
 	return idx;
 }
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index c92131edfaba..67763d3c7abf 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -662,10 +662,8 @@ static int vm_cmdline_set(const char *device,
 	pdev = platform_device_register_resndata(&vm_cmdline_parent,
 			"virtio-mmio", vm_cmdline_id++,
 			resources, ARRAY_SIZE(resources), NULL, 0);
-	if (IS_ERR(pdev))
-		return PTR_ERR(pdev);
 
-	return 0;
+	return PTR_ERR_OR_ZERO(pdev);
 }
 
 static int vm_cmdline_get_device(struct device *dev, void *data)
@@ -725,7 +723,7 @@ static void vm_unregister_cmdline_devices(void)
 
 /* Platform driver */
 
-static struct of_device_id virtio_mmio_match[] = {
+static const struct of_device_id virtio_mmio_match[] = {
 	{ .compatible = "virtio,mmio", },
 	{},
 };
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 1c4797e53f68..48d4d1cf1cb6 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -513,7 +513,7 @@ static void virtio_pci_release_dev(struct device *_d)
 static int virtio_pci_probe(struct pci_dev *pci_dev,
 			    const struct pci_device_id *id)
 {
-	struct virtio_pci_device *vp_dev;
+	struct virtio_pci_device *vp_dev, *reg_dev = NULL;
 	int rc;
 
 	/* allocate our structure and fill it out */
@@ -551,6 +551,7 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
 	pci_set_master(pci_dev);
 
 	rc = register_virtio_device(&vp_dev->vdev);
+	reg_dev = vp_dev;
 	if (rc)
 		goto err_register;
 
@@ -564,7 +565,10 @@ err_register:
 err_probe:
 	pci_disable_device(pci_dev);
 err_enable_device:
-	kfree(vp_dev);
+	if (reg_dev)
+		put_device(&vp_dev->vdev.dev);
+	else
+		kfree(vp_dev);
 	return rc;
 }
 
diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
index 343d7ddefe04..4e8b8304b793 100644
--- a/include/uapi/linux/virtio_balloon.h
+++ b/include/uapi/linux/virtio_balloon.h
@@ -52,7 +52,8 @@ struct virtio_balloon_config {
 #define VIRTIO_BALLOON_S_MEMFREE  4   /* Total amount of free memory */
 #define VIRTIO_BALLOON_S_MEMTOT   5   /* Total amount of memory */
 #define VIRTIO_BALLOON_S_AVAIL    6   /* Available memory as in /proc */
-#define VIRTIO_BALLOON_S_NR       7
+#define VIRTIO_BALLOON_S_CACHES   7   /* Disk caches */
+#define VIRTIO_BALLOON_S_NR       8
 
 /*
  * Memory statistics structure.
diff --git a/tools/virtio/ringtest/ring.c b/tools/virtio/ringtest/ring.c
index 747c5dd47be8..5a41404aaef5 100644
--- a/tools/virtio/ringtest/ring.c
+++ b/tools/virtio/ringtest/ring.c
@@ -84,12 +84,11 @@ void alloc_ring(void)
 		perror("Unable to allocate ring buffer.\n");
 		exit(3);
 	}
-	event = malloc(sizeof *event);
+	event = calloc(1, sizeof(*event));
 	if (!event) {
 		perror("Unable to allocate event buffer.\n");
 		exit(3);
 	}
-	memset(event, 0, sizeof *event);
 	guest.avail_idx = 0;
 	guest.kicked_avail_idx = -1;
 	guest.last_used_idx = 0;
@@ -102,12 +101,11 @@ void alloc_ring(void)
 		ring[i] = desc;
 	}
 	guest.num_free = ring_size;
-	data = malloc(ring_size * sizeof *data);
+	data = calloc(ring_size, sizeof(*data));
 	if (!data) {
 		perror("Unable to allocate data buffer.\n");
 		exit(3);
 	}
-	memset(data, 0, ring_size * sizeof *data);
 }
 
 /* guest side */
@@ -188,16 +186,18 @@ bool enable_call()
 
 void kick_available(void)
 {
+	bool need;
+
 	/* Flush in previous flags write */
 	/* Barrier C (for pairing) */
 	smp_mb();
-	if (!need_event(event->kick_index,
-			guest.avail_idx,
-			guest.kicked_avail_idx))
-		return;
+	need = need_event(event->kick_index,
+			   guest.avail_idx,
+			   guest.kicked_avail_idx);
 
 	guest.kicked_avail_idx = guest.avail_idx;
-	kick();
+	if (need)
+		kick();
 }
 
 /* host side */
@@ -253,14 +253,18 @@ bool use_buf(unsigned *lenp, void **bufp)
 
 void call_used(void)
 {
+	bool need;
+
 	/* Flush in previous flags write */
 	/* Barrier D (for pairing) */
 	smp_mb();
-	if (!need_event(event->call_index,
+
+	need = need_event(event->call_index,
 			host.used_idx,
-			host.called_used_idx))
-		return;
+			host.called_used_idx);
 
 	host.called_used_idx = host.used_idx;
-	call();
+
+	if (need)
+		call();
 }
diff --git a/tools/virtio/ringtest/virtio_ring_0_9.c b/tools/virtio/ringtest/virtio_ring_0_9.c
index bbc3043b2fb1..5fd3fbcb9e57 100644
--- a/tools/virtio/ringtest/virtio_ring_0_9.c
+++ b/tools/virtio/ringtest/virtio_ring_0_9.c
@@ -225,16 +225,18 @@ bool enable_call()
 
 void kick_available(void)
 {
+	bool need;
+
 	/* Flush in previous flags write */
 	/* Barrier C (for pairing) */
 	smp_mb();
-	if (!vring_need_event(vring_avail_event(&ring),
-			      guest.avail_idx,
-			      guest.kicked_avail_idx))
-		return;
+	need = vring_need_event(vring_avail_event(&ring),
+				guest.avail_idx,
+				guest.kicked_avail_idx);
 
 	guest.kicked_avail_idx = guest.avail_idx;
-	kick();
+	if (need)
+		kick();
 }
 
 /* host side */
@@ -316,14 +318,16 @@ bool use_buf(unsigned *lenp, void **bufp)
 
 void call_used(void)
 {
+	bool need;
+
 	/* Flush in previous flags write */
 	/* Barrier D (for pairing) */
 	smp_mb();
-	if (!vring_need_event(vring_used_event(&ring),
-			      host.used_idx,
-			      host.called_used_idx))
-		return;
+	need = vring_need_event(vring_used_event(&ring),
+				host.used_idx,
+				host.called_used_idx);
 
 	host.called_used_idx = host.used_idx;
-	call();
+	if (need)
+		call();
 }