tcm_vhost: Multi-target support

In order to take advantages of Paolo's multi-queue virito-scsi, we need
multi-target support in tcm_vhost first. Otherwise all the requests go
to one queue and other queues are idle.

This patch makes:

1. All the targets under the wwpn is seen and can be used by guest.
2. No need to pass the tpgt number in struct vhost_scsi_target to
   tcm_vhost.ko. Only wwpn is needed.
3. We can always pass max_target = 255 to guest now, since we abort the
   request who's target id does not exist.

Changes in v2:
- Handle non-contiguous tpgt

Changes in v3:
- Simplfy lock in vhost_scsi_set_endpoint
- Return -EEXIST when does not match

Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index 704e4f6..81ecda5 100644 (file)
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -59,8 +59,14 @@ enum {
        VHOST_SCSI_VQ_IO = 2,
 };
 
+#define VHOST_SCSI_MAX_TARGET 256
+
 struct vhost_scsi {
-       struct tcm_vhost_tpg *vs_tpg;   /* Protected by vhost_scsi->dev.mutex */
+       /* Protected by vhost_scsi->dev.mutex */
+       struct tcm_vhost_tpg *vs_tpg[VHOST_SCSI_MAX_TARGET];
+       char vs_vhost_wwpn[TRANSPORT_IQN_LEN];
+       bool vs_endpoint;
+
        struct vhost_dev dev;
        struct vhost_virtqueue vqs[3];
 
@@ -564,10 +570,10 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs)
        u32 exp_data_len, data_first, data_num, data_direction;
        unsigned out, in, i;
        int head, ret;
+       u8 target;
 
        /* Must use ioctl VHOST_SCSI_SET_ENDPOINT */
-       tv_tpg = vs->vs_tpg;
-       if (unlikely(!tv_tpg))
+       if (unlikely(!vs->vs_endpoint))
                return;
 
        mutex_lock(&vq->mutex);
@@ -635,6 +641,28 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs)
                        break;
                }
 
+               /* Extract the tpgt */
+               target = v_req.lun[1];
+               tv_tpg = vs->vs_tpg[target];
+
+               /* Target does not exist, fail the request */
+               if (unlikely(!tv_tpg)) {
+                       struct virtio_scsi_cmd_resp __user *resp;
+                       struct virtio_scsi_cmd_resp rsp;
+
+                       memset(&rsp, 0, sizeof(rsp));
+                       rsp.response = VIRTIO_SCSI_S_BAD_TARGET;
+                       resp = vq->iov[out].iov_base;
+                       ret = __copy_to_user(resp, &rsp, sizeof(rsp));
+                       if (!ret)
+                               vhost_add_used_and_signal(&vs->dev,
+                                               &vs->vqs[2], head, 0);
+                       else
+                               pr_err("Faulted on virtio_scsi_cmd_resp\n");
+
+                       continue;
+               }
+
                exp_data_len = 0;
                for (i = 0; i < data_num; i++)
                        exp_data_len += vq->iov[data_first + i].iov_len;
@@ -743,7 +771,8 @@ static int vhost_scsi_set_endpoint(
 {
        struct tcm_vhost_tport *tv_tport;
        struct tcm_vhost_tpg *tv_tpg;
-       int index;
+       bool match = false;
+       int index, ret;
 
        mutex_lock(&vs->dev.mutex);
        /* Verify that ring has been setup correctly. */
@@ -754,7 +783,6 @@ static int vhost_scsi_set_endpoint(
                        return -EFAULT;
                }
        }
-       mutex_unlock(&vs->dev.mutex);
 
        mutex_lock(&tcm_vhost_mutex);
        list_for_each_entry(tv_tpg, &tcm_vhost_list, tv_tpg_list) {
@@ -769,30 +797,33 @@ static int vhost_scsi_set_endpoint(
                }
                tv_tport = tv_tpg->tport;
 
-               if (!strcmp(tv_tport->tport_name, t->vhost_wwpn) &&
-                   (tv_tpg->tport_tpgt == t->vhost_tpgt)) {
-                       tv_tpg->tv_tpg_vhost_count++;
-                       mutex_unlock(&tv_tpg->tv_tpg_mutex);
-                       mutex_unlock(&tcm_vhost_mutex);
-
-                       mutex_lock(&vs->dev.mutex);
-                       if (vs->vs_tpg) {
-                               mutex_unlock(&vs->dev.mutex);
-                               mutex_lock(&tv_tpg->tv_tpg_mutex);
-                               tv_tpg->tv_tpg_vhost_count--;
+               if (!strcmp(tv_tport->tport_name, t->vhost_wwpn)) {
+                       if (vs->vs_tpg[tv_tpg->tport_tpgt]) {
                                mutex_unlock(&tv_tpg->tv_tpg_mutex);
+                               mutex_unlock(&tcm_vhost_mutex);
+                               mutex_unlock(&vs->dev.mutex);
                                return -EEXIST;
                        }
-
-                       vs->vs_tpg = tv_tpg;
+                       tv_tpg->tv_tpg_vhost_count++;
+                       vs->vs_tpg[tv_tpg->tport_tpgt] = tv_tpg;
                        smp_mb__after_atomic_inc();
-                       mutex_unlock(&vs->dev.mutex);
-                       return 0;
+                       match = true;
                }
                mutex_unlock(&tv_tpg->tv_tpg_mutex);
        }
        mutex_unlock(&tcm_vhost_mutex);
-       return -EINVAL;
+
+       if (match) {
+               memcpy(vs->vs_vhost_wwpn, t->vhost_wwpn,
+                      sizeof(vs->vs_vhost_wwpn));
+               vs->vs_endpoint = true;
+               ret = 0;
+       } else {
+               ret = -EEXIST;
+       }
+
+       mutex_unlock(&vs->dev.mutex);
+       return ret;
 }
 
 static int vhost_scsi_clear_endpoint(
@@ -801,7 +832,8 @@ static int vhost_scsi_clear_endpoint(
 {
        struct tcm_vhost_tport *tv_tport;
        struct tcm_vhost_tpg *tv_tpg;
-       int index, ret;
+       int index, ret, i;
+       u8 target;
 
        mutex_lock(&vs->dev.mutex);
        /* Verify that ring has been setup correctly. */
@@ -811,27 +843,32 @@ static int vhost_scsi_clear_endpoint(
                        goto err;
                }
        }
+       for (i = 0; i < VHOST_SCSI_MAX_TARGET; i++) {
+               target = i;
 
-       if (!vs->vs_tpg) {
-               ret = -ENODEV;
-               goto err;
-       }
-       tv_tpg = vs->vs_tpg;
-       tv_tport = tv_tpg->tport;
-
-       if (strcmp(tv_tport->tport_name, t->vhost_wwpn) ||
-           (tv_tpg->tport_tpgt != t->vhost_tpgt)) {
-               pr_warn("tv_tport->tport_name: %s, tv_tpg->tport_tpgt: %hu"
-                       " does not match t->vhost_wwpn: %s, t->vhost_tpgt: %hu\n",
-                       tv_tport->tport_name, tv_tpg->tport_tpgt,
-                       t->vhost_wwpn, t->vhost_tpgt);
-               ret = -EINVAL;
-               goto err;
+               tv_tpg = vs->vs_tpg[target];
+               if (!tv_tpg)
+                       continue;
+
+               tv_tport = tv_tpg->tport;
+               if (!tv_tport) {
+                       ret = -ENODEV;
+                       goto err;
+               }
+
+               if (strcmp(tv_tport->tport_name, t->vhost_wwpn)) {
+                       pr_warn("tv_tport->tport_name: %s, tv_tpg->tport_tpgt: %hu"
+                               " does not match t->vhost_wwpn: %s, t->vhost_tpgt: %hu\n",
+                               tv_tport->tport_name, tv_tpg->tport_tpgt,
+                               t->vhost_wwpn, t->vhost_tpgt);
+                       ret = -EINVAL;
+                       goto err;
+               }
+               tv_tpg->tv_tpg_vhost_count--;
+               vs->vs_tpg[target] = NULL;
+               vs->vs_endpoint = false;
        }
-       tv_tpg->tv_tpg_vhost_count--;
-       vs->vs_tpg = NULL;
        mutex_unlock(&vs->dev.mutex);
-
        return 0;
 
 err:
@@ -866,16 +903,12 @@ static int vhost_scsi_open(struct inode *inode, struct file *f)
 static int vhost_scsi_release(struct inode *inode, struct file *f)
 {
        struct vhost_scsi *s = f->private_data;
+       struct vhost_scsi_target t;
 
-       if (s->vs_tpg && s->vs_tpg->tport) {
-               struct vhost_scsi_target backend;
-
-               memcpy(backend.vhost_wwpn, s->vs_tpg->tport->tport_name,
-                               sizeof(backend.vhost_wwpn));
-               backend.vhost_tpgt = s->vs_tpg->tport_tpgt;
-               vhost_scsi_clear_endpoint(s, &backend);
-       }
-
+       mutex_lock(&s->dev.mutex);
+       memcpy(t.vhost_wwpn, s->vs_vhost_wwpn, sizeof(t.vhost_wwpn));
+       mutex_unlock(&s->dev.mutex);
+       vhost_scsi_clear_endpoint(s, &t);
        vhost_dev_stop(&s->dev);
        vhost_dev_cleanup(&s->dev, false);
        kfree(s);

diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h
index 47ee80b..519a550 100644 (file)
--- a/drivers/vhost/tcm_vhost.h
+++ b/drivers/vhost/tcm_vhost.h
@@ -93,9 +93,11 @@ struct tcm_vhost_tport {
  *
  * ABI Rev 0: July 2012 version starting point for v3.6-rc merge candidate +
  *            RFC-v2 vhost-scsi userspace.  Add GET_ABI_VERSION ioctl usage
+ * ABI Rev 1: January 2013. Ignore vhost_tpgt filed in struct vhost_scsi_target.
+ *            All the targets under vhost_wwpn can be seen and used by guset.
  */
 
-#define VHOST_SCSI_ABI_VERSION 0
+#define VHOST_SCSI_ABI_VERSION 1
 
 struct vhost_scsi_target {
        int abi_version;