Merge branch 'virtio-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull virtio changes from Rusty Russell:
 "New workflow: same git trees pulled by linux-next get sent straight to
  Linus.  Git is awkward at shuffling patches compared with quilt or mq,
  but that doesn't happen often once things get into my -next branch."

* 'virtio-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (24 commits)
  lguest: fix occasional crash in example launcher.
  virtio-blk: Disable callback in virtblk_done()
  virtio_mmio: Don't attempt to create empty virtqueues
  virtio_mmio: fix off by one error allocating queue
  drivers/virtio/virtio_pci.c: fix error return code
  virtio: don't crash when device is buggy
  virtio: remove CONFIG_VIRTIO_RING
  virtio: add help to CONFIG_VIRTIO option.
  virtio: support reserved vqs
  virtio: introduce an API to set affinity for a virtqueue
  virtio-ring: move queue_index to vring_virtqueue
  virtio_balloon: not EXPERIMENTAL any more.
  virtio-balloon: dependency fix
  virtio-blk: fix NULL checking in virtblk_alloc_req()
  virtio-blk: Add REQ_FLUSH and REQ_FUA support to bio path
  virtio-blk: Add bio-based IO path for virtio-blk
  virtio: console: fix error handling in init() function
  tools: Fix pthread flag for Makefile of trace-agent used by virtio-trace
  tools: Add guest trace agent as a user tool
  virtio/console: Allocate scatterlist according to the current pipe size
  ...

25 files changed, 1391 insertions, 106 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index f9acddd9ace3..c8af429991d9 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -656,7 +656,6 @@ config S390_GUEST
         depends on 64BIT && EXPERIMENTAL
         select VIRTUALIZATION
         select VIRTIO
-        select VIRTIO_RING
         select VIRTIO_CONSOLE
         help
           Enabling this option adds support for virtio based paravirtual device
diff --git a/arch/x86/lguest/Kconfig b/arch/x86/lguest/Kconfig
index 6e121a2a49e1..7872a3330fb5 100644
--- a/arch/x86/lguest/Kconfig
+++ b/arch/x86/lguest/Kconfig
@@ -4,7 +4,6 @@ config LGUEST_GUEST
         depends on X86_32
         select VIRTUALIZATION
         select VIRTIO
-        select VIRTIO_RING
         select VIRTIO_CONSOLE
         help
           Lguest is a tiny in-kernel hypervisor.  Selecting this will
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index c0bbeb470754..0bdde8fba397 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -14,6 +14,9 @@
 
 #define PART_BITS 4
 
+static bool use_bio;
+module_param(use_bio, bool, S_IRUGO);
+
 static int major;
 static DEFINE_IDA(vd_index_ida);
 
@@ -23,6 +26,7 @@ struct virtio_blk
 {
         struct virtio_device *vdev;
         struct virtqueue *vq;
+        wait_queue_head_t queue_wait;
 
         /* The disk structure for the kernel. */
         struct gendisk *disk;
@@ -51,53 +55,244 @@ struct virtio_blk
 struct virtblk_req
 {
         struct request *req;
+        struct bio *bio;
         struct virtio_blk_outhdr out_hdr;
         struct virtio_scsi_inhdr in_hdr;
+        struct work_struct work;
+        struct virtio_blk *vblk;
+        int flags;
         u8 status;
+        struct scatterlist sg[];
+};
+
+enum {
+        VBLK_IS_FLUSH           = 1,
+        VBLK_REQ_FLUSH          = 2,
+        VBLK_REQ_DATA           = 4,
+        VBLK_REQ_FUA            = 8,
 };
 
-static void blk_done(struct virtqueue *vq)
+static inline int virtblk_result(struct virtblk_req *vbr)
+{
+        switch (vbr->status) {
+        case VIRTIO_BLK_S_OK:
+                return 0;
+        case VIRTIO_BLK_S_UNSUPP:
+                return -ENOTTY;
+        default:
+                return -EIO;
+        }
+}
+
+static inline struct virtblk_req *virtblk_alloc_req(struct virtio_blk *vblk,
+                                                    gfp_t gfp_mask)
 {
-        struct virtio_blk *vblk = vq->vdev->priv;
         struct virtblk_req *vbr;
-        unsigned int len;
-        unsigned long flags;
 
-        spin_lock_irqsave(vblk->disk->queue->queue_lock, flags);
-        while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
-                int error;
+        vbr = mempool_alloc(vblk->pool, gfp_mask);
+        if (!vbr)
+                return NULL;
 
-                switch (vbr->status) {
-                case VIRTIO_BLK_S_OK:
-                        error = 0;
-                        break;
-                case VIRTIO_BLK_S_UNSUPP:
-                        error = -ENOTTY;
-                        break;
-                default:
-                        error = -EIO;
+        vbr->vblk = vblk;
+        if (use_bio)
+                sg_init_table(vbr->sg, vblk->sg_elems);
+
+        return vbr;
+}
+
+static void virtblk_add_buf_wait(struct virtio_blk *vblk,
+                                 struct virtblk_req *vbr,
+                                 unsigned long out,
+                                 unsigned long in)
+{
+        DEFINE_WAIT(wait);
+
+        for (;;) {
+                prepare_to_wait_exclusive(&vblk->queue_wait, &wait,
+                                          TASK_UNINTERRUPTIBLE);
+
+                spin_lock_irq(vblk->disk->queue->queue_lock);
+                if (virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr,
+                                      GFP_ATOMIC) < 0) {
+                        spin_unlock_irq(vblk->disk->queue->queue_lock);
+                        io_schedule();
+                } else {
+                        virtqueue_kick(vblk->vq);
+                        spin_unlock_irq(vblk->disk->queue->queue_lock);
                         break;
                 }
 
-                switch (vbr->req->cmd_type) {
-                case REQ_TYPE_BLOCK_PC:
-                        vbr->req->resid_len = vbr->in_hdr.residual;
-                        vbr->req->sense_len = vbr->in_hdr.sense_len;
-                        vbr->req->errors = vbr->in_hdr.errors;
-                        break;
-                case REQ_TYPE_SPECIAL:
-                        vbr->req->errors = (error != 0);
+        }
+
+        finish_wait(&vblk->queue_wait, &wait);
+}
+
+static inline void virtblk_add_req(struct virtblk_req *vbr,
+                                   unsigned int out, unsigned int in)
+{