230 lines
6.7 KiB
Diff
230 lines
6.7 KiB
Diff
From: Cong Meng <mc@linux.vnet.ibm.com>
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Date: Thu, 5 Jul 2012 17:06:43 +0800
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Subject: [07/12] [SCSI] virtio-scsi: hotplug support for virtio-scsi
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commit 365a7150094114a0f8ef0b6164e6b04b519039e8 upstream.
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This patch implements the hotplug support for virtio-scsi.
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When there is a device attached/detached, the virtio-scsi driver will be
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signaled via event virtual queue and it will add/remove the scsi device
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in question automatically.
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Signed-off-by: Sen Wang <senwang@linux.vnet.ibm.com>
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Signed-off-by: Cong Meng <mc@linux.vnet.ibm.com>
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Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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[bwh: Backported to 3.2: s/virtqueue_add_buf/&_gfp/]
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---
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drivers/scsi/virtio_scsi.c | 124 ++++++++++++++++++++++++++++++++++++++++++-
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include/linux/virtio_scsi.h | 9 ++++
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2 files changed, 132 insertions(+), 1 deletion(-)
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--- a/drivers/scsi/virtio_scsi.c
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+++ b/drivers/scsi/virtio_scsi.c
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@@ -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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+
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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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+
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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 vi
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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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+
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+ sg_set_buf(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
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+
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+ spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
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+
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+ ret = virtqueue_add_buf_gfp(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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+
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+ spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
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+
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+ return ret;
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+}
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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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+
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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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+
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+ return 0;
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+}
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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 v
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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_d
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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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+
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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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+
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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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+
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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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--- a/include/linux/virtio_scsi.h
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+++ b/include/linux/virtio_scsi.h
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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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+
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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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+
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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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