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authorRusty Russell <rusty@rustcorp.com.au>2008-02-04 23:50:03 -0500
committerRusty Russell <rusty@rustcorp.com.au>2008-02-04 07:50:03 -0500
commit6e5aa7efb27aec7e55b6463fa2c8db594c4226fa (patch)
tree060a955e711ac224136157a5410e88dcdab965af /include
parentb3369c1fb410fddeb38a404316c861395f6d6ae8 (diff)
virtio: reset function
A reset function solves three problems: 1) It allows us to renegotiate features, eg. if we want to upgrade a guest driver without rebooting the guest. 2) It gives us a clean way of shutting down virtqueues: after a reset, we know that the buffers won't be used by the host, and 3) It helps the guest recover from messed-up drivers. So we remove the ->shutdown hook, and the only way we now remove feature bits is via reset. We leave it to the driver to do the reset before it deletes queues: the balloon driver, for example, needs to chat to the host in its remove function. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'include')
-rw-r--r--include/linux/virtio.h5
-rw-r--r--include/linux/virtio_config.h4
2 files changed, 4 insertions, 5 deletions
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 78408d5237c1..260d1fcf29a4 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -45,9 +45,6 @@ struct virtqueue
45 * vq: the struct virtqueue we're talking about. 45 * vq: the struct virtqueue we're talking about.
46 * This returns "false" (and doesn't re-enable) if there are pending 46 * This returns "false" (and doesn't re-enable) if there are pending
47 * buffers in the queue, to avoid a race. 47 * buffers in the queue, to avoid a race.
48 * @shutdown: "unadd" all buffers.
49 * vq: the struct virtqueue we're talking about.
50 * Remove everything from the queue.
51 * 48 *
52 * Locking rules are straightforward: the driver is responsible for 49 * Locking rules are straightforward: the driver is responsible for
53 * locking. No two operations may be invoked simultaneously. 50 * locking. No two operations may be invoked simultaneously.
@@ -67,8 +64,6 @@ struct virtqueue_ops {
67 64
68 void (*disable_cb)(struct virtqueue *vq); 65 void (*disable_cb)(struct virtqueue *vq);
69 bool (*enable_cb)(struct virtqueue *vq); 66 bool (*enable_cb)(struct virtqueue *vq);
70
71 void (*shutdown)(struct virtqueue *vq);
72}; 67};
73 68
74/** 69/**
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 81f828ac8f47..d581b2914b34 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -43,6 +43,9 @@ struct virtio_device;
43 * @set_status: write the status byte 43 * @set_status: write the status byte
44 * vdev: the virtio_device 44 * vdev: the virtio_device
45 * status: the new status byte 45 * status: the new status byte
46 * @reset: reset the device
47 * vdev: the virtio device
48 * After this, status and feature negotiation must be done again
46 * @find_vq: find a virtqueue and instantiate it. 49 * @find_vq: find a virtqueue and instantiate it.
47 * vdev: the virtio_device 50 * vdev: the virtio_device
48 * index: the 0-based virtqueue number in case there's more than one. 51 * index: the 0-based virtqueue number in case there's more than one.
@@ -59,6 +62,7 @@ struct virtio_config_ops
59 const void *buf, unsigned len); 62 const void *buf, unsigned len);
60 u8 (*get_status)(struct virtio_device *vdev); 63 u8 (*get_status)(struct virtio_device *vdev);
61 void (*set_status)(struct virtio_device *vdev, u8 status); 64 void (*set_status)(struct virtio_device *vdev, u8 status);
65 void (*reset)(struct virtio_device *vdev);
62 struct virtqueue *(*find_vq)(struct virtio_device *vdev, 66 struct virtqueue *(*find_vq)(struct virtio_device *vdev,
63 unsigned index, 67 unsigned index,
64 void (*callback)(struct virtqueue *)); 68 void (*callback)(struct virtqueue *));