From 365a7150094114a0f8ef0b6164e6b04b519039e8 Mon Sep 17 00:00:00 2001 From: Cong Meng Date: Thu, 5 Jul 2012 17:06:43 +0800 Subject: [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 Signed-off-by: Cong Meng Acked-by: Paolo Bonzini Signed-off-by: James Bottomley --- drivers/scsi/virtio_scsi.c | 124 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 123 insertions(+), 1 deletion(-) (limited to 'drivers/scsi/virtio_scsi.c') diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index 9fc5e67a0ca..ae3bef7c523 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -25,6 +25,7 @@ #include #define VIRTIO_SCSI_MEMPOOL_SZ 64 +#define VIRTIO_SCSI_EVENT_LEN 8 /* Command queue element */ struct virtio_scsi_cmd { @@ -43,6 +44,12 @@ struct virtio_scsi_cmd { } resp; } ____cacheline_aligned_in_smp; +struct virtio_scsi_event_node { + struct virtio_scsi *vscsi; + struct virtio_scsi_event event; + struct work_struct work; +}; + struct virtio_scsi_vq { /* Protects vq */ spinlock_t vq_lock; @@ -67,6 +74,9 @@ struct virtio_scsi { struct virtio_scsi_vq event_vq; struct virtio_scsi_vq req_vq; + /* Get some buffers ready for event vq */ + struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN]; + struct virtio_scsi_target_state *tgt[]; }; @@ -202,6 +212,105 @@ static void virtscsi_ctrl_done(struct virtqueue *vq) spin_unlock_irqrestore(&vscsi->ctrl_vq.vq_lock, flags); }; +static int virtscsi_kick_event(struct virtio_scsi *vscsi, + struct virtio_scsi_event_node *event_node) +{ + int ret; + struct scatterlist sg; + unsigned long flags; + + sg_set_buf(&sg, &event_node->event, sizeof(struct virtio_scsi_event)); + + spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags); + + ret = virtqueue_add_buf(vscsi->event_vq.vq, &sg, 0, 1, event_node, GFP_ATOMIC); + if (ret >= 0) + virtqueue_kick(vscsi->event_vq.vq); + + spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags); + + return ret; +} + +static int virtscsi_kick_event_all(struct virtio_scsi *vscsi) +{ + int i; + + for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) { + vscsi->event_list[i].vscsi = vscsi; + virtscsi_kick_event(vscsi, &vscsi->event_list[i]); + } + + return 0; +} + +static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi) +{ + int i; + + for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) + cancel_work_sync(&vscsi->event_list[i].work); +} + +static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi, + struct virtio_scsi_event *event) +{ + struct scsi_device *sdev; + struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev); + unsigned int target = event->lun[1]; + unsigned int lun = (event->lun[2] << 8) | event->lun[3]; + + switch (event->reason) { + case VIRTIO_SCSI_EVT_RESET_RESCAN: + scsi_add_device(shost, 0, target, lun); + break; + case VIRTIO_SCSI_EVT_RESET_REMOVED: + sdev = scsi_device_lookup(shost, 0, target, lun); + if (sdev) { + scsi_remove_device(sdev); + scsi_device_put(sdev); + } else { + pr_err("SCSI device %d 0 %d %d not found\n", + shost->host_no, target, lun); + } + break; + default: + pr_info("Unsupport virtio scsi event reason %x\n", event->reason); + } +} + +static void virtscsi_handle_event(struct work_struct *work) +{ + struct virtio_scsi_event_node *event_node = + container_of(work, struct virtio_scsi_event_node, work); + struct virtio_scsi *vscsi = event_node->vscsi; + struct virtio_scsi_event *event = &event_node->event; + + if (event->event & VIRTIO_SCSI_T_EVENTS_MISSED) { + event->event &= ~VIRTIO_SCSI_T_EVENTS_MISSED; + scsi_scan_host(virtio_scsi_host(vscsi->vdev)); + } + + switch (event->event) { + case VIRTIO_SCSI_T_NO_EVENT: + break; + case VIRTIO_SCSI_T_TRANSPORT_RESET: + virtscsi_handle_transport_reset(vscsi, event); + break; + default: + pr_err("Unsupport virtio scsi event %x\n", event->event); + } + virtscsi_kick_event(vscsi, event_node); +} + +static void virtscsi_complete_event(void *buf) +{ + struct virtio_scsi_event_node *event_node = buf; + + INIT_WORK(&event_node->work, virtscsi_handle_event); + schedule_work(&event_node->work); +} + static void virtscsi_event_done(struct virtqueue *vq) { struct Scsi_Host *sh = virtio_scsi_host(vq->vdev); @@ -209,7 +318,7 @@ static void virtscsi_event_done(struct virtqueue *vq) unsigned long flags; spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags); - virtscsi_vq_done(vq, virtscsi_complete_free); + virtscsi_vq_done(vq, virtscsi_complete_event); spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags); }; @@ -510,6 +619,9 @@ static int virtscsi_init(struct virtio_device *vdev, virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE); virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE); + if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) + virtscsi_kick_event_all(vscsi); + /* We need to know how many segments before we allocate. */ sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1; @@ -580,6 +692,10 @@ virtscsi_init_failed: static void __devexit virtscsi_remove(struct virtio_device *vdev) { struct Scsi_Host *shost = virtio_scsi_host(vdev); + struct virtio_scsi *vscsi = shost_priv(shost); + + if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) + virtscsi_cancel_event_work(vscsi); scsi_remove_host(shost); @@ -608,7 +724,13 @@ static struct virtio_device_id id_table[] = { { 0 }, }; +static unsigned int features[] = { + VIRTIO_SCSI_F_HOTPLUG +}; + static struct virtio_driver virtio_scsi_driver = { + .feature_table = features, + .feature_table_size = ARRAY_SIZE(features), .driver.name = KBUILD_MODNAME, .driver.owner = THIS_MODULE, .id_table = id_table, -- cgit v1.2.3