Merge tag 'virtio-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus

Pull virtio update from Rusty Russell:
 "Virtio patches, mainly hotplugging fixes."

* tag 'virtio-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  virtio-blk: return VIRTIO_BLK_F_FLUSH to header.
  virtio-blk: allow toggling host cache between writeback and writethrough
  virtio-blk: Use block layer provided spinlock
  virtio-blk: Reset device after blk_cleanup_queue()
  virtio-blk: Call del_gendisk() before disable guest kick
  virtio: rng: s3/s4 support
  virtio: rng: split out common code in probe / remove for s3/s4 ops
  virtio: rng: don't wait on host when module is going away
  virtio: rng: allow tasks to be killed that are waiting for rng input
  virtio ids: fix comment for virtio-rng

4 files changed, 137 insertions, 27 deletions

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 693187d..c0bbeb4 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -21,8 +21,6 @@ struct workqueue_struct *virtblk_wq;
 
 struct virtio_blk
 {
-	spinlock_t lock;
-
 	struct virtio_device *vdev;
 	struct virtqueue *vq;
 
@@ -65,7 +63,7 @@ static void blk_done(struct virtqueue *vq)
 	unsigned int len;
 	unsigned long flags;
 
-	spin_lock_irqsave(&vblk->lock, flags);
+	spin_lock_irqsave(vblk->disk->queue->queue_lock, flags);
 	while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
 		int error;
 
@@ -99,7 +97,7 @@ static void blk_done(struct virtqueue *vq)
 	}
 	/* In case queue is stopped waiting for more buffers. */
 	blk_start_queue(vblk->disk->queue);
-	spin_unlock_irqrestore(&vblk->lock, flags);
+	spin_unlock_irqrestore(vblk->disk->queue->queue_lock, flags);
 }
 
 static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
@@ -397,6 +395,83 @@ static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
 	return 0;
 }
 
+static int virtblk_get_cache_mode(struct virtio_device *vdev)
+{
+	u8 writeback;
+	int err;
+
+	err = virtio_config_val(vdev, VIRTIO_BLK_F_CONFIG_WCE,
+				offsetof(struct virtio_blk_config, wce),
+				&writeback);
+	if (err)
+		writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE);
+
+	return writeback;
+}
+
+static void virtblk_update_cache_mode(struct virtio_device *vdev)
+{
+	u8 writeback = virtblk_get_cache_mode(vdev);
+	struct virtio_blk *vblk = vdev->priv;
+
+	if (writeback)
+		blk_queue_flush(vblk->disk->queue, REQ_FLUSH);
+	else
+		blk_queue_flush(vblk->disk->queue, 0);
+
+	revalidate_disk(vblk->disk);
+}
+
+static const char *const virtblk_cache_types[] = {
+	"write through", "write back"
+};
+
+static ssize_t
+virtblk_cache_type_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	struct gendisk *disk = dev_to_disk(dev);
+	struct virtio_blk *vblk = disk->private_data;
+	struct virtio_device *vdev = vblk->vdev;
+	int i;
+	u8 writeback;
+
+	BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
+	for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; )
+		if (sysfs_streq(buf, virtblk_cache_types[i]))
+			break;
+
+	if (i < 0)
+		return -EINVAL;
+
+	writeback = i;
+	vdev->config->set(vdev,
+			  offsetof(struct virtio_blk_config, wce),
+			  &writeback, sizeof(writeback));
+
+	virtblk_update_cache_mode(vdev);
+	return count;
+}
+
+static ssize_t
+virtblk_cache_type_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct gendisk *disk = dev_to_disk(dev);
+	struct virtio_blk *vblk = disk->private_data;
+	u8 writeback = virtblk_get_cache_mode(vblk->vdev);
+
+	BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
+	return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]);
+}
+
+static const struct device_attribute dev_attr_cache_type_ro =
+	__ATTR(cache_type, S_IRUGO,
+	       virtblk_cache_type_show, NULL);
+static const struct device_attribute dev_attr_cache_type_rw =
+	__ATTR(cache_type, S_IRUGO|S_IWUSR,
+	       virtblk_cache_type_show, virtblk_cache_type_store);
+
 static int __devinit virtblk_probe(struct virtio_device *vdev)
 {
 	struct virtio_blk *vblk;
@@ -431,7 +506,6 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
 		goto out_free_index;
 	}
 
-	spin_lock_init(&vblk->lock);
 	vblk->vdev = vdev;
 	vblk->sg_elems = sg_elems;
 	sg_init_table(vblk->sg, vblk->sg_elems);
@@ -456,7 +530,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
 		goto out_mempool;
 	}
 
-	q = vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
+	q = vblk->disk->queue = blk_init_queue(do_virtblk_request, NULL);
 	if (!q) {
 		err = -ENOMEM;
 		goto out_put_disk;
@@ -474,8 +548,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
 	vblk->index = index;
 
 	/* configure queue flush support */
-	if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
-		blk_queue_flush(q, REQ_FLUSH);
+	virtblk_update_cache_mode(vdev);
 
 	/* If disk is read-only in the host, the guest should obey */
 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
@@ -553,6 +626,14 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
 	if (err)
 		goto out_del_disk;
 
+	if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
+		err = device_create_file(disk_to_dev(vblk->disk),
+					 &dev_attr_cache_type_rw);
+	else
+		err = device_create_file(disk_to_dev(vblk->disk),
+					 &dev_attr_cache_type_ro);
+	if (err)
+		goto out_del_disk;
 	return 0;
 
 out_del_disk:
@@ -576,30 +657,20 @@ static void __devexit virtblk_remove(struct virtio_device *vdev)
 {
 	struct virtio_blk *vblk = vdev->priv;
 	int index = vblk->index;
-	struct virtblk_req *vbr;
-	unsigned long flags;
 
 	/* Prevent config work handler from accessing the device. */
 	mutex_lock(&vblk->config_lock);
 	vblk->config_enable = false;
 	mutex_unlock(&vblk->config_lock);
 
+	del_gendisk(vblk->disk);
+	blk_cleanup_queue(vblk->disk->queue);
+
 	/* Stop all the virtqueues. */
 	vdev->config->reset(vdev);
 
 	flush_work(&vblk->config_work);
 
-	del_gendisk(vblk->disk);
-
-	/* Abort requests dispatched to driver. */
-	spin_lock_irqsave(&vblk->lock, flags);
-	while ((vbr = virtqueue_detach_unused_buf(vblk->vq))) {
-		__blk_end_request_all(vbr->req, -EIO);
-		mempool_free(vbr, vblk->pool);
-	}
-	spin_unlock_irqrestore(&vblk->lock, flags);
-
-	blk_cleanup_queue(vblk->disk->queue);
 	put_disk(vblk->disk);
 	mempool_destroy(vblk->pool);
 	vdev->config->del_vqs(vdev);
@@ -655,7 +726,7 @@ static const struct virtio_device_id id_table[] = {
 static unsigned int features[] = {
 	VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
 	VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
-	VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY
+	VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE
 };
 
 /*
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index 723725b..5708299 100644
--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -55,6 +55,7 @@ static void register_buffer(u8 *buf, size_t size)
 
 static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
 {
+	int ret;
 
 	if (!busy) {
 		busy = true;
@@ -65,7 +66,9 @@ static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
 	if (!wait)
 		return 0;
 
-	wait_for_completion(&have_data);
+	ret = wait_for_completion_killable(&have_data);
+	if (ret < 0)
+		return ret;
 
 	busy = false;
 
@@ -85,7 +88,7 @@ static struct hwrng virtio_hwrng = {
 	.read		= virtio_read,
 };
 
-static int virtrng_probe(struct virtio_device *vdev)
+static int probe_common(struct virtio_device *vdev)
 {
 	int err;
 
@@ -103,13 +106,37 @@ static int virtrng_probe(struct virtio_device *vdev)
 	return 0;
 }
 
-static void __devexit virtrng_remove(struct virtio_device *vdev)
+static void remove_common(struct virtio_device *vdev)
 {
 	vdev->config->reset(vdev);
+	busy = false;
 	hwrng_unregister(&virtio_hwrng);
 	vdev->config->del_vqs(vdev);
 }
 
+static int virtrng_probe(struct virtio_device *vdev)
+{
+	return probe_common(vdev);
+}
+
+static void __devexit virtrng_remove(struct virtio_device *vdev)
+{
+	remove_common(vdev);
+}
+
+#ifdef CONFIG_PM
+static int virtrng_freeze(struct virtio_device *vdev)
+{
+	remove_common(vdev);
+	return 0;
+}
+
+static int virtrng_restore(struct virtio_device *vdev)
+{
+	return probe_common(vdev);
+}
+#endif
+
 static struct virtio_device_id id_table[] = {
 	{ VIRTIO_ID_RNG, VIRTIO_DEV_ANY_ID },
 	{ 0 },
@@ -121,6 +148,10 @@ static struct virtio_driver virtio_rng_driver = {
 	.id_table =	id_table,
 	.probe =	virtrng_probe,
 	.remove =	__devexit_p(virtrng_remove),
+#ifdef CONFIG_PM
+	.freeze =	virtrng_freeze,
+	.restore =	virtrng_restore,
+#endif
 };
 
 static int __init init(void)
diff --git a/include/linux/virtio_blk.h b/include/linux/virtio_blk.h
index e0edb40..6d8e61c 100644
--- a/include/linux/virtio_blk.h
+++ b/include/linux/virtio_blk.h
@@ -37,8 +37,14 @@
 #define VIRTIO_BLK_F_RO		5	/* Disk is read-only */
 #define VIRTIO_BLK_F_BLK_SIZE	6	/* Block size of disk is available*/
 #define VIRTIO_BLK_F_SCSI	7	/* Supports scsi command passthru */
-#define VIRTIO_BLK_F_FLUSH	9	/* Cache flush command support */
+#define VIRTIO_BLK_F_WCE	9	/* Writeback mode enabled after reset */
 #define VIRTIO_BLK_F_TOPOLOGY	10	/* Topology information is available */
+#define VIRTIO_BLK_F_CONFIG_WCE	11	/* Writeback mode available in config */
+
+#ifndef __KERNEL__
+/* Old (deprecated) name for VIRTIO_BLK_F_WCE. */
+#define VIRTIO_BLK_F_FLUSH VIRTIO_BLK_F_WCE
+#endif
 
 #define VIRTIO_BLK_ID_BYTES	20	/* ID string length */
 
@@ -69,6 +75,8 @@ struct virtio_blk_config {
 	/* optimal sustained I/O size in logical blocks. */
 	__u32 opt_io_size;
 
+	/* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
+	__u8 wce;
 } __attribute__((packed));
 
 /*
diff --git a/include/linux/virtio_ids.h b/include/linux/virtio_ids.h
index 7529b85..270fb22 100644
--- a/include/linux/virtio_ids.h
+++ b/include/linux/virtio_ids.h
@@ -32,7 +32,7 @@
 #define VIRTIO_ID_NET		1 /* virtio net */
 #define VIRTIO_ID_BLOCK		2 /* virtio block */
 #define VIRTIO_ID_CONSOLE	3 /* virtio console */
-#define VIRTIO_ID_RNG		4 /* virtio ring */
+#define VIRTIO_ID_RNG		4 /* virtio rng */
 #define VIRTIO_ID_BALLOON	5 /* virtio balloon */
 #define VIRTIO_ID_RPMSG		7 /* virtio remote processor messaging */
 #define VIRTIO_ID_SCSI		8 /* virtio scsi */