[SCSI] virtio-scsi: hotplug support for virtio-scsi
This patch implements the hotplug support for virtio-scsi. When there is a device attached/detached, the virtio-scsi driver will be signaled via event virtual queue and it will add/remove the scsi device in question automatically. Signed-off-by: Sen Wang <senwang@linux.vnet.ibm.com> Signed-off-by: Cong Meng <mc@linux.vnet.ibm.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Cong Meng
James Bottomley
parent
2bd37f0fde
commit
365a715009
@ -25,6 +25,7 @@
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#include <scsi/scsi_cmnd.h>
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#define VIRTIO_SCSI_MEMPOOL_SZ 64
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#define VIRTIO_SCSI_EVENT_LEN 8
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/* Command queue element */
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struct virtio_scsi_cmd {
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@ -43,6 +44,12 @@ struct virtio_scsi_cmd {
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} resp;
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} ____cacheline_aligned_in_smp;
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struct virtio_scsi_event_node {
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struct virtio_scsi *vscsi;
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struct virtio_scsi_event event;
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struct work_struct work;
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};
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struct virtio_scsi_vq {
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/* Protects vq */
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spinlock_t vq_lock;
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@ -67,6 +74,9 @@ struct virtio_scsi {
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struct virtio_scsi_vq event_vq;
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struct virtio_scsi_vq req_vq;
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/* Get some buffers ready for event vq */
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struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
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struct virtio_scsi_target_state *tgt[];
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};
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@ -202,6 +212,105 @@ static void virtscsi_ctrl_done(struct virtqueue *vq)
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spin_unlock_irqrestore(&vscsi->ctrl_vq.vq_lock, flags);
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};
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static int virtscsi_kick_event(struct virtio_scsi *vscsi,
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struct virtio_scsi_event_node *event_node)
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{
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int ret;
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struct scatterlist sg;
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unsigned long flags;
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sg_set_buf(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
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spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
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ret = virtqueue_add_buf(vscsi->event_vq.vq, &sg, 0, 1, event_node, GFP_ATOMIC);
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if (ret >= 0)
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virtqueue_kick(vscsi->event_vq.vq);
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spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
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return ret;
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}
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static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
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{
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int i;
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for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
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vscsi->event_list[i].vscsi = vscsi;
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virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
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}
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return 0;
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}
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static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
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{
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int i;
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for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
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cancel_work_sync(&vscsi->event_list[i].work);
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}
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static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
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struct virtio_scsi_event *event)
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{
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struct scsi_device *sdev;
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struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
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unsigned int target = event->lun[1];
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unsigned int lun = (event->lun[2] << 8) | event->lun[3];
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switch (event->reason) {
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case VIRTIO_SCSI_EVT_RESET_RESCAN:
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scsi_add_device(shost, 0, target, lun);
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break;
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case VIRTIO_SCSI_EVT_RESET_REMOVED:
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sdev = scsi_device_lookup(shost, 0, target, lun);
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if (sdev) {
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scsi_remove_device(sdev);
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scsi_device_put(sdev);
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} else {
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pr_err("SCSI device %d 0 %d %d not found\n",
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shost->host_no, target, lun);
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}
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break;
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default:
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pr_info("Unsupport virtio scsi event reason %x\n", event->reason);
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}
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}
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static void virtscsi_handle_event(struct work_struct *work)
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{
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struct virtio_scsi_event_node *event_node =
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container_of(work, struct virtio_scsi_event_node, work);
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struct virtio_scsi *vscsi = event_node->vscsi;
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struct virtio_scsi_event *event = &event_node->event;
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if (event->event & VIRTIO_SCSI_T_EVENTS_MISSED) {
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event->event &= ~VIRTIO_SCSI_T_EVENTS_MISSED;
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scsi_scan_host(virtio_scsi_host(vscsi->vdev));
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}
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switch (event->event) {
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case VIRTIO_SCSI_T_NO_EVENT:
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break;
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case VIRTIO_SCSI_T_TRANSPORT_RESET:
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virtscsi_handle_transport_reset(vscsi, event);
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break;
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default:
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pr_err("Unsupport virtio scsi event %x\n", event->event);
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}
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virtscsi_kick_event(vscsi, event_node);
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}
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static void virtscsi_complete_event(void *buf)
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{
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struct virtio_scsi_event_node *event_node = buf;
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INIT_WORK(&event_node->work, virtscsi_handle_event);
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schedule_work(&event_node->work);
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}
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static void virtscsi_event_done(struct virtqueue *vq)
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{
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struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
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@ -209,7 +318,7 @@ static void virtscsi_event_done(struct virtqueue *vq)
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unsigned long flags;
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spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
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virtscsi_vq_done(vq, virtscsi_complete_free);
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virtscsi_vq_done(vq, virtscsi_complete_event);
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spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
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};
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@ -510,6 +619,9 @@ static int virtscsi_init(struct virtio_device *vdev,
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virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
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virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
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if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
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virtscsi_kick_event_all(vscsi);
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/* We need to know how many segments before we allocate. */
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sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
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@ -580,6 +692,10 @@ virtscsi_init_failed:
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static void __devexit virtscsi_remove(struct virtio_device *vdev)
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{
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struct Scsi_Host *shost = virtio_scsi_host(vdev);
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struct virtio_scsi *vscsi = shost_priv(shost);
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if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
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virtscsi_cancel_event_work(vscsi);
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scsi_remove_host(shost);
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@ -608,7 +724,13 @@ static struct virtio_device_id id_table[] = {
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{ 0 },
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};
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static unsigned int features[] = {
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VIRTIO_SCSI_F_HOTPLUG
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};
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static struct virtio_driver virtio_scsi_driver = {
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.feature_table = features,
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.feature_table_size = ARRAY_SIZE(features),
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.driver.name = KBUILD_MODNAME,
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.driver.owner = THIS_MODULE,
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.id_table = id_table,
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@ -69,6 +69,10 @@ struct virtio_scsi_config {
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u32 max_lun;
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} __packed;
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/* Feature Bits */
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#define VIRTIO_SCSI_F_INOUT 0
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#define VIRTIO_SCSI_F_HOTPLUG 1
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/* Response codes */
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#define VIRTIO_SCSI_S_OK 0
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#define VIRTIO_SCSI_S_OVERRUN 1
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@ -105,6 +109,11 @@ struct virtio_scsi_config {
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#define VIRTIO_SCSI_T_TRANSPORT_RESET 1
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#define VIRTIO_SCSI_T_ASYNC_NOTIFY 2
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/* Reasons of transport reset event */
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#define VIRTIO_SCSI_EVT_RESET_HARD 0
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#define VIRTIO_SCSI_EVT_RESET_RESCAN 1
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#define VIRTIO_SCSI_EVT_RESET_REMOVED 2
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#define VIRTIO_SCSI_S_SIMPLE 0
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#define VIRTIO_SCSI_S_ORDERED 1
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#define VIRTIO_SCSI_S_HEAD 2
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