File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
new file mode 100644
index 0000000..03a2aad
--- /dev/null
+++ b/drivers/scsi/virtio_scsi.c
@@ -0,0 +1,1177 @@
+/*
+ * Virtio SCSI HBA driver
+ *
+ * Copyright IBM Corp. 2010
+ * Copyright Red Hat, Inc. 2011
+ *
+ * Authors:
+ * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
+ * Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/mempool.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_scsi.h>
+#include <linux/cpu.h>
+#include <linux/blkdev.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_tcq.h>
+#include <linux/seqlock.h>
+
+#define VIRTIO_SCSI_MEMPOOL_SZ 64
+#define VIRTIO_SCSI_EVENT_LEN 8
+#define VIRTIO_SCSI_VQ_BASE 2
+
+/* Command queue element */
+struct virtio_scsi_cmd {
+ struct scsi_cmnd *sc;
+ struct completion *comp;
+ union {
+ struct virtio_scsi_cmd_req cmd;
+ struct virtio_scsi_cmd_req_pi cmd_pi;
+ struct virtio_scsi_ctrl_tmf_req tmf;
+ struct virtio_scsi_ctrl_an_req an;
+ } req;
+ union {
+ struct virtio_scsi_cmd_resp cmd;
+ struct virtio_scsi_ctrl_tmf_resp tmf;
+ struct virtio_scsi_ctrl_an_resp an;
+ struct virtio_scsi_event evt;
+ } 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;
+
+ struct virtqueue *vq;
+};
+
+/*
+ * Per-target queue state.
+ *
+ * This struct holds the data needed by the queue steering policy. When a
+ * target is sent multiple requests, we need to drive them to the same queue so
+ * that FIFO processing order is kept. However, if a target was idle, we can
+ * choose a queue arbitrarily. In this case the queue is chosen according to
+ * the current VCPU, so the driver expects the number of request queues to be
+ * equal to the number of VCPUs. This makes it easy and fast to select the
+ * queue, and also lets the driver optimize the IRQ affinity for the virtqueues
+ * (each virtqueue's affinity is set to the CPU that "owns" the queue).
+ *
+ * tgt_seq is held to serialize reading and writing req_vq.
+ *
+ * Decrements of reqs are never concurrent with writes of req_vq: before the
+ * decrement reqs will be != 0; after the decrement the virtqueue completion
+ * routine will not use the req_vq so it can be changed by a new request.
+ * Thus they can happen outside the tgt_seq, provided of course we make reqs
+ * an atomic_t.
+ */
+struct virtio_scsi_target_state {
+ seqcount_t tgt_seq;
+
+ /* Count of outstanding requests. */
+ atomic_t reqs;
+
+ /* Currently active virtqueue for requests sent to this target. */
+ struct virtio_scsi_vq *req_vq;
+};
+
+/* Driver instance state */
+struct virtio_scsi {
+ struct virtio_device *vdev;
+
+ /* Get some buffers ready for event vq */
+ struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
+
+ u32 num_queues;
+
+ /* If the affinity hint is set for virtqueues */
+ bool affinity_hint_set;
+
+ /* CPU hotplug notifier */
+ struct notifier_block nb;
+
+ /* Protected by event_vq lock */
+ bool stop_events;
+
+ struct virtio_scsi_vq ctrl_vq;
+ struct virtio_scsi_vq event_vq;
+ struct virtio_scsi_vq req_vqs[];
+};
+
+static struct kmem_cache *virtscsi_cmd_cache;
+static mempool_t *virtscsi_cmd_pool;
+
+static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
+{
+ return vdev->priv;
+}
+
+static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
+{
+ if (!resid)
+ return;
+
+ if (!scsi_bidi_cmnd(sc)) {
+ scsi_set_resid(sc, resid);
+ return;
+ }
+
+ scsi_in(sc)->resid = min(resid, scsi_in(sc)->length);
+ scsi_out(sc)->resid = resid - scsi_in(sc)->resid;
+}
+
+/**
+ * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
+ *
+ * Called with vq_lock held.
+ */
+static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
+{
+ struct virtio_scsi_cmd *cmd = buf;
+ struct scsi_cmnd *sc = cmd->sc;
+ struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
+ struct virtio_scsi_target_state *tgt =
+ scsi_target(sc->device)->hostdata;
+
+ dev_dbg(&sc->device->sdev_gendev,
+ "cmd %p response %u status %#02x sense_len %u\n",
+ sc, resp->response, resp->status, resp->sense_len);
+
+ sc->result = resp->status;
+ virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid));
+ switch (resp->response) {
+ case VIRTIO_SCSI_S_OK:
+ set_host_byte(sc, DID_OK);
+ break;
+ case VIRTIO_SCSI_S_OVERRUN:
+ set_host_byte(sc, DID_ERROR);
+ break;
+ case VIRTIO_SCSI_S_ABORTED:
+ set_host_byte(sc, DID_ABORT);
+ break;
+ case VIRTIO_SCSI_S_BAD_TARGET:
+ set_host_byte(sc, DID_BAD_TARGET);
+ break;
+ case VIRTIO_SCSI_S_RESET:
+ set_host_byte(sc, DID_RESET);
+ break;
+ case VIRTIO_SCSI_S_BUSY:
+ set_host_byte(sc, DID_BUS_BUSY);
+ break;
+ case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
+ set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
+ break;
+ case VIRTIO_SCSI_S_TARGET_FAILURE:
+ set_host_byte(sc, DID_TARGET_FAILURE);
+ break;
+ case VIRTIO_SCSI_S_NEXUS_FAILURE:
+ set_host_byte(sc, DID_NEXUS_FAILURE);
+ break;
+ default:
+ scmd_printk(KERN_WARNING, sc, "Unknown response %d",
+ resp->response);
+ /* fall through */
+ case VIRTIO_SCSI_S_FAILURE:
+ set_host_byte(sc, DID_ERROR);
+ break;
+ }
+
+ WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) >
+ VIRTIO_SCSI_SENSE_SIZE);
+ if (sc->sense_buffer) {
+ memcpy(sc->sense_buffer, resp->sense,
+ min_t(u32,
+ virtio32_to_cpu(vscsi->vdev, resp->sense_len),
+ VIRTIO_SCSI_SENSE_SIZE));
+ if (resp->sense_len)
+ set_driver_byte(sc, DRIVER_SENSE);
+ }
+
+ sc->scsi_done(sc);
+
+ atomic_dec(&tgt->reqs);
+}
+
+static void virtscsi_vq_done(struct virtio_scsi *vscsi,
+ struct virtio_scsi_vq *virtscsi_vq,
+ void (*fn)(struct virtio_scsi *vscsi, void *buf))
+{
+ void *buf;
+ unsigned int len;
+ unsigned long flags;
+ struct virtqueue *vq = virtscsi_vq->vq;
+
+ spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
+ do {
+ virtqueue_disable_cb(vq);
+ while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
+ fn(vscsi, buf);
+
+ if (unlikely(virtqueue_is_broken(vq)))
+ break;
+ } while (!virtqueue_enable_cb(vq));
+ spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
+}
+
+static void virtscsi_req_done(struct virtqueue *vq)
+{
+ struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
+ struct virtio_scsi *vscsi = shost_priv(sh);
+ int index = vq->index - VIRTIO_SCSI_VQ_BASE;
+ struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
+
+ virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
+};
+
+static void virtscsi_poll_requests(struct virtio_scsi *vscsi)
+{
+ int i, num_vqs;
+
+ num_vqs = vscsi->num_queues;
+ for (i = 0; i < num_vqs; i++)
+ virtscsi_vq_done(vscsi, &vscsi->req_vqs[i],
+ virtscsi_complete_cmd);
+}
+
+static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
+{
+ struct virtio_scsi_cmd *cmd = buf;
+
+ if (cmd->comp)
+ complete_all(cmd->comp);
+}
+
+static void virtscsi_ctrl_done(struct virtqueue *vq)
+{
+ struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
+ struct virtio_scsi *vscsi = shost_priv(sh);
+
+ virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
+};
+
+static void virtscsi_handle_event(struct work_struct *work);
+
+static int virtscsi_kick_event(struct virtio_scsi *vscsi,
+ struct virtio_scsi_event_node *event_node)
+{
+ int err;
+ struct scatterlist sg;
+ unsigned long flags;
+
+ INIT_WORK(&event_node->work, virtscsi_handle_event);
+ sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
+
+ spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
+
+ err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
+ GFP_ATOMIC);
+ if (!err)
+ virtqueue_kick(vscsi->event_vq.vq);
+
+ spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
+
+ return err;
+}
+
+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;
+
+ /* Stop scheduling work before calling cancel_work_sync. */
+ spin_lock_irq(&vscsi->event_vq.vq_lock);
+ vscsi->stop_events = true;
+ spin_unlock_irq(&vscsi->event_vq.vq_lock);
+
+ 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 (virtio32_to_cpu(vscsi->vdev, 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_param_change(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];
+ u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255;
+ u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8;
+
+ sdev = scsi_device_lookup(shost, 0, target, lun);
+ if (!sdev) {
+ pr_err("SCSI device %d 0 %d %d not found\n",
+ shost->host_no, target, lun);
+ return;
+ }
+
+ /* Handle "Parameters changed", "Mode parameters changed", and
+ "Capacity data has changed". */
+ if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
+ scsi_rescan_device(&sdev->sdev_gendev);
+
+ scsi_device_put(sdev);
+}
+
+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 &
+ cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) {
+ event->event &= ~cpu_to_virtio32(vscsi->vdev,
+ VIRTIO_SCSI_T_EVENTS_MISSED);
+ scsi_scan_host(virtio_scsi_host(vscsi->vdev));
+ }
+
+ switch (virtio32_to_cpu(vscsi->vdev, event->event)) {
+ case VIRTIO_SCSI_T_NO_EVENT:
+ break;
+ case VIRTIO_SCSI_T_TRANSPORT_RESET:
+ virtscsi_handle_transport_reset(vscsi, event);
+ break;
+ case VIRTIO_SCSI_T_PARAM_CHANGE:
+ virtscsi_handle_param_change(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(struct virtio_scsi *vscsi, void *buf)
+{
+ struct virtio_scsi_event_node *event_node = buf;
+
+ if (!vscsi->stop_events)
+ queue_work(system_freezable_wq, &event_node->work);
+}
+
+static void virtscsi_event_done(struct virtqueue *vq)
+{
+ struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
+ struct virtio_scsi *vscsi = shost_priv(sh);
+
+ virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
+};
+
+/**
+ * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue
+ * @vq : the struct virtqueue we're talking about
+ * @cmd : command structure
+ * @req_size : size of the request buffer
+ * @resp_size : size of the response buffer
+ */
+static int virtscsi_add_cmd(struct virtqueue *vq,
+ struct virtio_scsi_cmd *cmd,
+ size_t req_size, size_t resp_size)
+{
+ struct scsi_cmnd *sc = cmd->sc;
+ struct scatterlist *sgs[6], req, resp;
+ struct sg_table *out, *in;
+ unsigned out_num = 0, in_num = 0;
+
+ out = in = NULL;
+
+ if (sc && sc->sc_data_direction != DMA_NONE) {
+ if (sc->sc_data_direction != DMA_FROM_DEVICE)
+ out = &scsi_out(sc)->table;
+ if (sc->sc_data_direction != DMA_TO_DEVICE)
+ in = &scsi_in(sc)->table;
+ }
+
+ /* Request header. */
+ sg_init_one(&req, &cmd->req, req_size);
+ sgs[out_num++] = &req;
+
+ /* Data-out buffer. */
+ if (out) {
+ /* Place WRITE protection SGLs before Data OUT payload */
+ if (scsi_prot_sg_count(sc))
+ sgs[out_num++] = scsi_prot_sglist(sc);
+ sgs[out_num++] = out->sgl;
+ }
+
+ /* Response header. */
+ sg_init_one(&resp, &cmd->resp, resp_size);
+ sgs[out_num + in_num++] = &resp;
+
+ /* Data-in buffer */
+ if (in) {
+ /* Place READ protection SGLs before Data IN payload */
+ if (scsi_prot_sg_count(sc))
+ sgs[out_num + in_num++] = scsi_prot_sglist(sc);
+ sgs[out_num + in_num++] = in->sgl;
+ }
+
+ return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
+}
+
+static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq,
+ struct virtio_scsi_cmd *cmd,
+ size_t req_size, size_t resp_size)
+{
+ unsigned long flags;
+ int err;
+ bool needs_kick = false;
+
+ spin_lock_irqsave(&vq->vq_lock, flags);
+ err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
+ if (!err)
+ needs_kick = virtqueue_kick_prepare(vq->vq);
+
+ spin_unlock_irqrestore(&vq->vq_lock, flags);
+
+ if (needs_kick)
+ virtqueue_notify(vq->vq);
+ return err;
+}
+
+static void virtio_scsi_init_hdr(struct virtio_device *vdev,
+ struct virtio_scsi_cmd_req *cmd,
+ struct scsi_cmnd *sc)
+{
+ cmd->lun[0] = 1;
+ cmd->lun[1] = sc->device->id;
+ cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
+ cmd->lun[3] = sc->device->lun & 0xff;
+ cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc);
+ cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
+ cmd->prio = 0;
+ cmd->crn = 0;
+}
+
+#ifdef CONFIG_BLK_DEV_INTEGRITY
+static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
+ struct virtio_scsi_cmd_req_pi *cmd_pi,
+ struct scsi_cmnd *sc)
+{
+ struct request *rq = sc->request;
+ struct blk_integrity *bi;
+
+ virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc);
+
+ if (!rq || !scsi_prot_sg_count(sc))
+ return;
+
+ bi = blk_get_integrity(rq->rq_disk);
+
+ if (sc->sc_data_direction == DMA_TO_DEVICE)
+ cmd_pi->pi_bytesout = cpu_to_virtio32(vdev,
+ blk_rq_sectors(rq) *
+ bi->tuple_size);
+ else if (sc->sc_data_direction == DMA_FROM_DEVICE)
+ cmd_pi->pi_bytesin = cpu_to_virtio32(vdev,
+ blk_rq_sectors(rq) *
+ bi->tuple_size);
+}
+#endif
+
+static int virtscsi_queuecommand(struct virtio_scsi *vscsi,
+ struct virtio_scsi_vq *req_vq,
+ struct scsi_cmnd *sc)
+{
+ struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
+ struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
+ unsigned long flags;
+ int req_size;
+ int ret;
+
+ BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
+
+ /* TODO: check feature bit and fail if unsupported? */
+ BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
+
+ dev_dbg(&sc->device->sdev_gendev,
+ "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
+
+ memset(cmd, 0, sizeof(*cmd));
+ cmd->sc = sc;
+
+ BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
+
+#ifdef CONFIG_BLK_DEV_INTEGRITY
+ if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) {
+ virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc);
+ memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
+ req_size = sizeof(cmd->req.cmd_pi);
+ } else
+#endif
+ {
+ virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc);
+ memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
+ req_size = sizeof(cmd->req.cmd);
+ }
+
+ ret = virtscsi_kick_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd));
+ if (ret == -EIO) {
+ cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
+ spin_lock_irqsave(&req_vq->vq_lock, flags);
+ virtscsi_complete_cmd(vscsi, cmd);
+ spin_unlock_irqrestore(&req_vq->vq_lock, flags);
+ } else if (ret != 0) {
+ return SCSI_MLQUEUE_HOST_BUSY;
+ }
+ return 0;
+}
+
+static int virtscsi_queuecommand_single(struct Scsi_Host *sh,
+ struct scsi_cmnd *sc)
+{
+ struct virtio_scsi *vscsi = shost_priv(sh);
+ struct virtio_scsi_target_state *tgt =
+ scsi_target(sc->device)->hostdata;
+
+ atomic_inc(&tgt->reqs);
+ return virtscsi_queuecommand(vscsi, &vscsi->req_vqs[0], sc);
+}
+
+static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
+ struct scsi_cmnd *sc)
+{
+ u32 tag = blk_mq_unique_tag(sc->request);
+ u16 hwq = blk_mq_unique_tag_to_hwq(tag);
+
+ return &vscsi->req_vqs[hwq];
+}
+
+static struct virtio_scsi_vq *virtscsi_pick_vq(struct virtio_scsi *vscsi,
+ struct virtio_scsi_target_state *tgt)
+{
+ struct virtio_scsi_vq *vq;
+ unsigned long flags;
+ u32 queue_num;
+
+ local_irq_save(flags);
+ if (atomic_inc_return(&tgt->reqs) > 1) {
+ unsigned long seq;
+
+ do {
+ seq = read_seqcount_begin(&tgt->tgt_seq);
+ vq = tgt->req_vq;
+ } while (read_seqcount_retry(&tgt->tgt_seq, seq));
+ } else {
+ /* no writes can be concurrent because of atomic_t */
+ write_seqcount_begin(&tgt->tgt_seq);
+
+ /* keep previous req_vq if a reader just arrived */
+ if (unlikely(atomic_read(&tgt->reqs) > 1)) {
+ vq = tgt->req_vq;
+ goto unlock;
+ }
+
+ queue_num = smp_processor_id();
+ while (unlikely(queue_num >= vscsi->num_queues))
+ queue_num -= vscsi->num_queues;
+ tgt->req_vq = vq = &vscsi->req_vqs[queue_num];
+ unlock:
+ write_seqcount_end(&tgt->tgt_seq);
+ }
+ local_irq_restore(flags);
+
+ return vq;
+}
+
+static int virtscsi_queuecommand_multi(struct Scsi_Host *sh,
+ struct scsi_cmnd *sc)
+{
+ struct virtio_scsi *vscsi = shost_priv(sh);
+ struct virtio_scsi_target_state *tgt =
+ scsi_target(sc->device)->hostdata;
+ struct virtio_scsi_vq *req_vq;
+
+ if (shost_use_blk_mq(sh))
+ req_vq = virtscsi_pick_vq_mq(vscsi, sc);
+ else
+ req_vq = virtscsi_pick_vq(vscsi, tgt);
+
+ return virtscsi_queuecommand(vscsi, req_vq, sc);
+}
+
+static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
+{
+ DECLARE_COMPLETION_ONSTACK(comp);
+ int ret = FAILED;
+
+ cmd->comp = ∁
+ if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd,
+ sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0)
+ goto out;
+
+ wait_for_completion(&comp);
+ if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
+ cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
+ ret = SUCCESS;
+
+ /*
+ * The spec guarantees that all requests related to the TMF have
+ * been completed, but the callback might not have run yet if
+ * we're using independent interrupts (e.g. MSI). Poll the
+ * virtqueues once.
+ *
+ * In the abort case, sc->scsi_done will do nothing, because
+ * the block layer must have detected a timeout and as a result
+ * REQ_ATOM_COMPLETE has been set.
+ */
+ virtscsi_poll_requests(vscsi);
+
+out:
+ mempool_free(cmd, virtscsi_cmd_pool);
+ return ret;
+}
+
+static int virtscsi_device_reset(struct scsi_cmnd *sc)
+{
+ struct virtio_scsi *vscsi = shost_priv(sc->device->host);
+ struct virtio_scsi_cmd *cmd;
+
+ sdev_printk(KERN_INFO, sc->device, "device reset\n");
+ cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
+ if (!cmd)
+ return FAILED;
+
+ memset(cmd, 0, sizeof(*cmd));
+ cmd->sc = sc;
+ cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
+ .type = VIRTIO_SCSI_T_TMF,
+ .subtype = cpu_to_virtio32(vscsi->vdev,
+ VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET),
+ .lun[0] = 1,
+ .lun[1] = sc->device->id,
+ .lun[2] = (sc->device->lun >> 8) | 0x40,
+ .lun[3] = sc->device->lun & 0xff,
+ };
+ return virtscsi_tmf(vscsi, cmd);
+}
+
+/**
+ * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth
+ * @sdev: Virtscsi target whose queue depth to change
+ * @qdepth: New queue depth
+ */
+static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
+{
+ struct Scsi_Host *shost = sdev->host;
+ int max_depth = shost->cmd_per_lun;
+
+ return scsi_change_queue_depth(sdev, min(max_depth, qdepth));
+}
+
+static int virtscsi_abort(struct scsi_cmnd *sc)
+{
+ struct virtio_scsi *vscsi = shost_priv(sc->device->host);
+ struct virtio_scsi_cmd *cmd;
+
+ scmd_printk(KERN_INFO, sc, "abort\n");
+ cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
+ if (!cmd)
+ return FAILED;
+
+ memset(cmd, 0, sizeof(*cmd));
+ cmd->sc = sc;
+ cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
+ .type = VIRTIO_SCSI_T_TMF,
+ .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
+ .lun[0] = 1,
+ .lun[1] = sc->device->id,
+ .lun[2] = (sc->device->lun >> 8) | 0x40,
+ .lun[3] = sc->device->lun & 0xff,
+ .tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc),
+ };
+ return virtscsi_tmf(vscsi, cmd);
+}
+
+static int virtscsi_target_alloc(struct scsi_target *starget)
+{
+ struct Scsi_Host *sh = dev_to_shost(starget->dev.parent);
+ struct virtio_scsi *vscsi = shost_priv(sh);
+
+ struct virtio_scsi_target_state *tgt =
+ kmalloc(sizeof(*tgt), GFP_KERNEL);
+ if (!tgt)
+ return -ENOMEM;
+
+ seqcount_init(&tgt->tgt_seq);
+ atomic_set(&tgt->reqs, 0);
+ tgt->req_vq = &vscsi->req_vqs[0];
+
+ starget->hostdata = tgt;
+ return 0;
+}
+
+static void virtscsi_target_destroy(struct scsi_target *starget)
+{
+ struct virtio_scsi_target_state *tgt = starget->hostdata;
+ kfree(tgt);
+}
+
+static struct scsi_host_template virtscsi_host_template_single = {
+ .module = THIS_MODULE,
+ .name = "Virtio SCSI HBA",
+ .proc_name = "virtio_scsi",
+ .this_id = -1,
+ .cmd_size = sizeof(struct virtio_scsi_cmd),
+ .queuecommand = virtscsi_queuecommand_single,
+ .change_queue_depth = virtscsi_change_queue_depth,
+ .eh_abort_handler = virtscsi_abort,
+ .eh_device_reset_handler = virtscsi_device_reset,
+
+ .can_queue = 1024,
+ .dma_boundary = UINT_MAX,
+ .use_clustering = ENABLE_CLUSTERING,
+ .target_alloc = virtscsi_target_alloc,
+ .target_destroy = virtscsi_target_destroy,
+ .track_queue_depth = 1,
+};
+
+static struct scsi_host_template virtscsi_host_template_multi = {
+ .module = THIS_MODULE,
+ .name = "Virtio SCSI HBA",
+ .proc_name = "virtio_scsi",
+ .this_id = -1,
+ .cmd_size = sizeof(struct virtio_scsi_cmd),
+ .queuecommand = virtscsi_queuecommand_multi,
+ .change_queue_depth = virtscsi_change_queue_depth,
+ .eh_abort_handler = virtscsi_abort,
+ .eh_device_reset_handler = virtscsi_device_reset,
+
+ .can_queue = 1024,
+ .dma_boundary = UINT_MAX,
+ .use_clustering = ENABLE_CLUSTERING,
+ .target_alloc = virtscsi_target_alloc,
+ .target_destroy = virtscsi_target_destroy,
+ .track_queue_depth = 1,
+};
+
+#define virtscsi_config_get(vdev, fld) \
+ ({ \
+ typeof(((struct virtio_scsi_config *)0)->fld) __val; \
+ virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
+ __val; \
+ })
+
+#define virtscsi_config_set(vdev, fld, val) \
+ do { \
+ typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
+ virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
+ } while(0)
+
+static void __virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
+{
+ int i;
+ int cpu;
+
+ /* In multiqueue mode, when the number of cpu is equal
+ * to the number of request queues, we let the qeueues
+ * to be private to one cpu by setting the affinity hint
+ * to eliminate the contention.
+ */
+ if ((vscsi->num_queues == 1 ||
+ vscsi->num_queues != num_online_cpus()) && affinity) {
+ if (vscsi->affinity_hint_set)
+ affinity = false;
+ else
+ return;
+ }
+
+ if (affinity) {
+ i = 0;
+ for_each_online_cpu(cpu) {
+ virtqueue_set_affinity(vscsi->req_vqs[i].vq, cpu);
+ i++;
+ }
+
+ vscsi->affinity_hint_set = true;
+ } else {
+ for (i = 0; i < vscsi->num_queues; i++) {
+ if (!vscsi->req_vqs[i].vq)
+ continue;
+
+ virtqueue_set_affinity(vscsi->req_vqs[i].vq, -1);
+ }
+
+ vscsi->affinity_hint_set = false;
+ }
+}
+
+static void virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
+{
+ get_online_cpus();
+ __virtscsi_set_affinity(vscsi, affinity);
+ put_online_cpus();
+}
+
+static int virtscsi_cpu_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ struct virtio_scsi *vscsi = container_of(nfb, struct virtio_scsi, nb);
+ switch(action) {
+ case CPU_ONLINE:
+ case CPU_ONLINE_FROZEN:
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ __virtscsi_set_affinity(vscsi, true);
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
+ struct virtqueue *vq)
+{
+ spin_lock_init(&virtscsi_vq->vq_lock);
+ virtscsi_vq->vq = vq;
+}
+
+static void virtscsi_remove_vqs(struct virtio_device *vdev)
+{
+ struct Scsi_Host *sh = virtio_scsi_host(vdev);
+ struct virtio_scsi *vscsi = shost_priv(sh);
+
+ virtscsi_set_affinity(vscsi, false);
+
+ /* Stop all the virtqueues. */
+ vdev->config->reset(vdev);
+
+ vdev->config->del_vqs(vdev);
+}
+
+static int virtscsi_init(struct virtio_device *vdev,
+ struct virtio_scsi *vscsi)
+{
+ int err;
+ u32 i;
+ u32 num_vqs;
+ vq_callback_t **callbacks;
+ const char **names;
+ struct virtqueue **vqs;
+
+ num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
+ vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL);
+ callbacks = kmalloc(num_vqs * sizeof(vq_callback_t *), GFP_KERNEL);
+ names = kmalloc(num_vqs * sizeof(char *), GFP_KERNEL);
+
+ if (!callbacks || !vqs || !names) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ callbacks[0] = virtscsi_ctrl_done;
+ callbacks[1] = virtscsi_event_done;
+ names[0] = "control";
+ names[1] = "event";
+ for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
+ callbacks[i] = virtscsi_req_done;
+ names[i] = "request";
+ }
+
+ /* Discover virtqueues and write information to configuration. */
+ err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
+ if (err)
+ goto out;
+
+ virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
+ virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
+ for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
+ virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
+ vqs[i]);
+
+ virtscsi_set_affinity(vscsi, true);
+
+ virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
+ virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
+
+ err = 0;
+
+out:
+ kfree(names);
+ kfree(callbacks);
+ kfree(vqs);
+ if (err)
+ virtscsi_remove_vqs(vdev);
+ return err;
+}
+
+static int virtscsi_probe(struct virtio_device *vdev)
+{
+ struct Scsi_Host *shost;
+ struct virtio_scsi *vscsi;
+ int err;
+ u32 sg_elems, num_targets;
+ u32 cmd_per_lun;
+ u32 num_queues;
+ struct scsi_host_template *hostt;
+
+ if (!vdev->config->get) {
+ dev_err(&vdev->dev, "%s failure: config access disabled\n",
+ __func__);
+ return -EINVAL;
+ }
+
+ /* We need to know how many queues before we allocate. */
+ num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
+
+ num_targets = virtscsi_config_get(vdev, max_target) + 1;
+
+ if (num_queues == 1)
+ hostt = &virtscsi_host_template_single;
+ else
+ hostt = &virtscsi_host_template_multi;
+
+ shost = scsi_host_alloc(hostt,
+ sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues);
+ if (!shost)
+ return -ENOMEM;
+
+ sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
+ shost->sg_tablesize = sg_elems;
+ vscsi = shost_priv(shost);
+ vscsi->vdev = vdev;
+ vscsi->num_queues = num_queues;
+ vdev->priv = shost;
+
+ err = virtscsi_init(vdev, vscsi);
+ if (err)
+ goto virtscsi_init_failed;
+
+ vscsi->nb.notifier_call = &virtscsi_cpu_callback;
+ err = register_hotcpu_notifier(&vscsi->nb);
+ if (err) {
+ pr_err("registering cpu notifier failed\n");
+ goto scsi_add_host_failed;
+ }
+
+ cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
+ shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
+ shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
+
+ /* LUNs > 256 are reported with format 1, so they go in the range
+ * 16640-32767.
+ */
+ shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
+ shost->max_id = num_targets;
+ shost->max_channel = 0;
+ shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
+ shost->nr_hw_queues = num_queues;
+
+#ifdef CONFIG_BLK_DEV_INTEGRITY
+ if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
+ int host_prot;
+
+ host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
+ SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
+ SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
+
+ scsi_host_set_prot(shost, host_prot);
+ scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
+ }
+#endif
+
+ err = scsi_add_host(shost, &vdev->dev);
+ if (err)
+ goto scsi_add_host_failed;
+
+ virtio_device_ready(vdev);
+
+ if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
+ virtscsi_kick_event_all(vscsi);
+
+ scsi_scan_host(shost);
+ return 0;
+
+scsi_add_host_failed:
+ vdev->config->del_vqs(vdev);
+virtscsi_init_failed:
+ scsi_host_put(shost);
+ return err;
+}
+
+static void 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);
+
+ unregister_hotcpu_notifier(&vscsi->nb);
+
+ virtscsi_remove_vqs(vdev);
+ scsi_host_put(shost);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int virtscsi_freeze(struct virtio_device *vdev)
+{
+ struct Scsi_Host *sh = virtio_scsi_host(vdev);
+ struct virtio_scsi *vscsi = shost_priv(sh);
+
+ unregister_hotcpu_notifier(&vscsi->nb);
+ virtscsi_remove_vqs(vdev);
+ return 0;
+}
+
+static int virtscsi_restore(struct virtio_device *vdev)
+{
+ struct Scsi_Host *sh = virtio_scsi_host(vdev);
+ struct virtio_scsi *vscsi = shost_priv(sh);
+ int err;
+
+ err = virtscsi_init(vdev, vscsi);
+ if (err)
+ return err;
+
+ err = register_hotcpu_notifier(&vscsi->nb);
+ if (err) {
+ vdev->config->del_vqs(vdev);
+ return err;
+ }
+
+ virtio_device_ready(vdev);
+
+ if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
+ virtscsi_kick_event_all(vscsi);
+
+ return err;
+}
+#endif
+
+static struct virtio_device_id id_table[] = {
+ { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
+ { 0 },
+};
+
+static unsigned int features[] = {
+ VIRTIO_SCSI_F_HOTPLUG,
+ VIRTIO_SCSI_F_CHANGE,
+#ifdef CONFIG_BLK_DEV_INTEGRITY
+ VIRTIO_SCSI_F_T10_PI,
+#endif
+};
+
+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,
+ .probe = virtscsi_probe,
+#ifdef CONFIG_PM_SLEEP
+ .freeze = virtscsi_freeze,
+ .restore = virtscsi_restore,
+#endif
+ .remove = virtscsi_remove,
+};
+
+static int __init init(void)
+{
+ int ret = -ENOMEM;
+
+ virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
+ if (!virtscsi_cmd_cache) {
+ pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
+ goto error;
+ }
+
+
+ virtscsi_cmd_pool =
+ mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
+ virtscsi_cmd_cache);
+ if (!virtscsi_cmd_pool) {
+ pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
+ goto error;
+ }
+ ret = register_virtio_driver(&virtio_scsi_driver);
+ if (ret < 0)
+ goto error;
+
+ return 0;
+
+error:
+ if (virtscsi_cmd_pool) {
+ mempool_destroy(virtscsi_cmd_pool);
+ virtscsi_cmd_pool = NULL;
+ }
+ if (virtscsi_cmd_cache) {
+ kmem_cache_destroy(virtscsi_cmd_cache);
+ virtscsi_cmd_cache = NULL;
+ }
+ return ret;
+}
+
+static void __exit fini(void)
+{
+ unregister_virtio_driver(&virtio_scsi_driver);
+ mempool_destroy(virtscsi_cmd_pool);
+ kmem_cache_destroy(virtscsi_cmd_cache);
+}
+module_init(init);
+module_exit(fini);
+
+MODULE_DEVICE_TABLE(virtio, id_table);
+MODULE_DESCRIPTION("Virtio SCSI HBA driver");
+MODULE_LICENSE("GPL");