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: Cong Meng <[email protected]> Signed-off-by: Sen Wang <[email protected]> --- drivers/scsi/virtio_scsi.c | 109 ++++++++++++++++++++++++++++++++++++++++++- include/linux/virtio_scsi.h | 9 ++++ 2 files changed, 116 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index 1b38431..6dad625 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 { @@ -43,9 +44,15 @@ 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; +}; + /* Driver instance state */ struct virtio_scsi { - /* Protects ctrl_vq, req_vq and sg[] */ + /* Protects ctrl_vq, event_vq, req_vq and sg[] */ spinlock_t vq_lock; struct virtio_device *vdev; @@ -53,6 +60,9 @@ struct virtio_scsi { struct virtqueue *event_vq; struct virtqueue *req_vq; + /* Get some buffers reday for event vq */ + struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN]; + /* For sglist construction when adding commands to the virtqueue. */ struct scatterlist sg[]; }; @@ -184,9 +194,93 @@ static void virtscsi_ctrl_done(struct virtqueue *vq) virtscsi_vq_done(vq, virtscsi_complete_free); }; +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->vq_lock, flags); + + ret = virtqueue_add_buf(vscsi->event_vq, &sg, 0, 1, event_node, GFP_ATOMIC); + if (ret >= 0) + virtqueue_kick(vscsi->event_vq); + + spin_unlock_irqrestore(&vscsi->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; + + switch (event->event) { + 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) { - virtscsi_vq_done(vq, virtscsi_complete_free); + virtscsi_vq_done(vq, virtscsi_complete_event); }; static void virtscsi_map_sgl(struct scatterlist *sg, unsigned int *p_idx, @@ -435,6 +529,11 @@ 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); + } + return 0; } @@ -532,7 +631,13 @@ 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 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
