lkml.org 
[lkml]   [2012]   [Jul]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v4] virtio-scsi: hotplug support for virtio-scsi
Date
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.

v2: handle no_event event
v3: add handle event dropped, and typo fix
v4: Cancel event works when exit. Coding type fix.

Signed-off-by: Sen Wang <senwang@linux.vnet.ibm.com>
Signed-off-by: Cong Meng <mc@linux.vnet.ibm.com>
---
drivers/scsi/virtio_scsi.c | 127 ++++++++++++++++++++++++++++++++++++++++++-
include/linux/virtio_scsi.h | 9 +++
2 files changed, 135 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 9fc5e67..173cb39 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -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 +212,106 @@ 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 +319,7 @@ 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 +620,10 @@ 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 +694,11 @@ 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 +727,13 @@ 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,
diff --git a/include/linux/virtio_scsi.h b/include/linux/virtio_scsi.h
index 8ddeafd..dc8d305 100644
--- a/include/linux/virtio_scsi.h
+++ b/include/linux/virtio_scsi.h
@@ -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
--
1.7.7.6


\
 
 \ /
  Last update: 2012-07-05 11:41    [W:0.065 / U:31.400 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site