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[SCSI] virtio-scsi: hotplug support for virtio-scsi

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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 2012-07-05 17:06:43 +08:00 committed by James Bottomley
parent 2bd37f0fde
commit 365a715009
2 changed files with 132 additions and 1 deletions
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124
drivers/scsi/virtio_scsi.c
View File

@ -25,6 +25,7 @@
#include <scsi/scsi_cmnd.h>
#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,

9
include/linux/virtio_scsi.h
View File

@ -69,6 +69,10 @@ struct virtio_scsi_config {
u32 max_lun;
} __packed;
/* Feature Bits */
#define VIRTIO_SCSI_F_INOUT 0
#define VIRTIO_SCSI_F_HOTPLUG 1
/* Response codes */
#define VIRTIO_SCSI_S_OK 0
#define VIRTIO_SCSI_S_OVERRUN 1
@ -105,6 +109,11 @@ struct virtio_scsi_config {
#define VIRTIO_SCSI_T_TRANSPORT_RESET 1
#define VIRTIO_SCSI_T_ASYNC_NOTIFY 2
/* Reasons of transport reset event */
#define VIRTIO_SCSI_EVT_RESET_HARD 0
#define VIRTIO_SCSI_EVT_RESET_RESCAN 1
#define VIRTIO_SCSI_EVT_RESET_REMOVED 2
#define VIRTIO_SCSI_S_SIMPLE 0
#define VIRTIO_SCSI_S_ORDERED 1
#define VIRTIO_SCSI_S_HEAD 2