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
Signed-off-by: Sen Wang <senwang at linux.vnet.ibm.com>
Signed-off-by: Cong Meng <mc at linux.vnet.ibm.com>
---
drivers/scsi/virtio_scsi.c | 113 ++++++++++++++++++++++++++++++++++++++++++-
include/linux/virtio_scsi.h | 9 ++++
2 files changed, 121 insertions(+), 1 deletions(-)
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 9fc5e67..d87446b 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 +212,97 @@ 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_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 +310,7 @@ 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 +611,10 @@ 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;
@@ -608,7 +713,13 @@ 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
Paolo Bonzini
2012-Jul-05 07:24 UTC
[PATCH v3] virtio-scsi: hotplug support for virtio-scsi
Il 05/07/2012 09:09, Cong Meng ha scritto:> 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 > > Signed-off-by: Sen Wang <senwang at linux.vnet.ibm.com> > Signed-off-by: Cong Meng <mc at linux.vnet.ibm.com> > --- > drivers/scsi/virtio_scsi.c | 113 ++++++++++++++++++++++++++++++++++++++++++- > include/linux/virtio_scsi.h | 9 ++++ > 2 files changed, 121 insertions(+), 1 deletions(-) > > diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c > index 9fc5e67..d87446b 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 +212,97 @@ 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_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);Coding standard (no parentheses on the right hand side of operators). Also, you're missing a loop that calls cancel_work_sync in virtscsi_remove. I believe with these changes we're good to go. Thanks again, and sorry for missing the cancel_work_sync issue so far. Paolo> + 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 +310,7 @@ 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 +611,10 @@ 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; > > @@ -608,7 +713,13 @@ 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 >