diff options
| -rw-r--r-- | drivers/vhost/tcm_vhost.c | 144 |
1 files changed, 101 insertions, 43 deletions
diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c index dd9614eb2577..6cda137bb208 100644 --- a/drivers/vhost/tcm_vhost.c +++ b/drivers/vhost/tcm_vhost.c @@ -74,9 +74,8 @@ enum { struct vhost_scsi { /* Protected by vhost_scsi->dev.mutex */ - struct tcm_vhost_tpg *vs_tpg[VHOST_SCSI_MAX_TARGET]; + struct tcm_vhost_tpg **vs_tpg; char vs_vhost_wwpn[TRANSPORT_IQN_LEN]; - bool vs_endpoint; struct vhost_dev dev; struct vhost_virtqueue vqs[VHOST_SCSI_MAX_VQ]; @@ -582,6 +581,7 @@ static void tcm_vhost_submission_work(struct work_struct *work) static void vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) { + struct tcm_vhost_tpg **vs_tpg; struct virtio_scsi_cmd_req v_req; struct tcm_vhost_tpg *tv_tpg; struct tcm_vhost_cmd *tv_cmd; @@ -590,8 +590,16 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs, int head, ret; u8 target; - /* Must use ioctl VHOST_SCSI_SET_ENDPOINT */ - if (unlikely(!vs->vs_endpoint)) + /* + * We can handle the vq only after the endpoint is setup by calling the + * VHOST_SCSI_SET_ENDPOINT ioctl. + * + * TODO: Check that we are running from vhost_worker which acts + * as read-side critical section for vhost kind of RCU. + * See the comments in struct vhost_virtqueue in drivers/vhost/vhost.h + */ + vs_tpg = rcu_dereference_check(vq->private_data, 1); + if (!vs_tpg) return; mutex_lock(&vq->mutex); @@ -661,7 +669,7 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs, /* Extract the tpgt */ target = v_req.lun[1]; - tv_tpg = ACCESS_ONCE(vs->vs_tpg[target]); + tv_tpg = ACCESS_ONCE(vs_tpg[target]); /* Target does not exist, fail the request */ if (unlikely(!tv_tpg)) { @@ -780,6 +788,20 @@ static void vhost_scsi_handle_kick(struct vhost_work *work) vhost_scsi_handle_vq(vs, vq); } +static void vhost_scsi_flush_vq(struct vhost_scsi *vs, int index) +{ + vhost_poll_flush(&vs->dev.vqs[index].poll); +} + +static void vhost_scsi_flush(struct vhost_scsi *vs) +{ + int i; + + for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) + vhost_scsi_flush_vq(vs, i); + vhost_work_flush(&vs->dev, &vs->vs_completion_work); +} + /* * Called from vhost_scsi_ioctl() context to walk the list of available * tcm_vhost_tpg with an active struct tcm_vhost_nexus @@ -790,8 +812,10 @@ static int vhost_scsi_set_endpoint( { struct tcm_vhost_tport *tv_tport; struct tcm_vhost_tpg *tv_tpg; + struct tcm_vhost_tpg **vs_tpg; + struct vhost_virtqueue *vq; + int index, ret, i, len; bool match = false; - int index, ret; mutex_lock(&vs->dev.mutex); /* Verify that ring has been setup correctly. */ @@ -803,6 +827,15 @@ static int vhost_scsi_set_endpoint( } } + len = sizeof(vs_tpg[0]) * VHOST_SCSI_MAX_TARGET; + vs_tpg = kzalloc(len, GFP_KERNEL); + if (!vs_tpg) { + mutex_unlock(&vs->dev.mutex); + return -ENOMEM; + } + if (vs->vs_tpg) + memcpy(vs_tpg, vs->vs_tpg, len); + mutex_lock(&tcm_vhost_mutex); list_for_each_entry(tv_tpg, &tcm_vhost_list, tv_tpg_list) { mutex_lock(&tv_tpg->tv_tpg_mutex); @@ -817,14 +850,15 @@ static int vhost_scsi_set_endpoint( tv_tport = tv_tpg->tport; if (!strcmp(tv_tport->tport_name, t->vhost_wwpn)) { - if (vs->vs_tpg[tv_tpg->tport_tpgt]) { + if (vs->vs_tpg && vs->vs_tpg[tv_tpg->tport_tpgt]) { mutex_unlock(&tv_tpg->tv_tpg_mutex); mutex_unlock(&tcm_vhost_mutex); mutex_unlock(&vs->dev.mutex); + kfree(vs_tpg); return -EEXIST; } tv_tpg->tv_tpg_vhost_count++; - vs->vs_tpg[tv_tpg->tport_tpgt] = tv_tpg; + vs_tpg[tv_tpg->tport_tpgt] = tv_tpg; smp_mb__after_atomic_inc(); match = true; } @@ -835,12 +869,26 @@ static int vhost_scsi_set_endpoint( if (match) { memcpy(vs->vs_vhost_wwpn, t->vhost_wwpn, sizeof(vs->vs_vhost_wwpn)); - vs->vs_endpoint = true; + for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) { + vq = &vs->vqs[i]; + /* Flushing the vhost_work acts as synchronize_rcu */ + mutex_lock(&vq->mutex); + rcu_assign_pointer(vq->private_data, vs_tpg); + mutex_unlock(&vq->mutex); + } ret = 0; } else { ret = -EEXIST; } + /* + * Act as synchronize_rcu to make sure access to + * old vs->vs_tpg is finished. + */ + vhost_scsi_flush(vs); + kfree(vs->vs_tpg); + vs->vs_tpg = vs_tpg; + mutex_unlock(&vs->dev.mutex); return ret; } @@ -851,6 +899,8 @@ static int vhost_scsi_clear_endpoint( { struct tcm_vhost_tport *tv_tport; struct tcm_vhost_tpg *tv_tpg; + struct vhost_virtqueue *vq; + bool match = false; int index, ret, i; u8 target; @@ -862,9 +912,14 @@ static int vhost_scsi_clear_endpoint( goto err_dev; } } + + if (!vs->vs_tpg) { + mutex_unlock(&vs->dev.mutex); + return 0; + } + for (i = 0; i < VHOST_SCSI_MAX_TARGET; i++) { target = i; - tv_tpg = vs->vs_tpg[target]; if (!tv_tpg) continue; @@ -886,10 +941,27 @@ static int vhost_scsi_clear_endpoint( } tv_tpg->tv_tpg_vhost_count--; vs->vs_tpg[target] = NULL; - vs->vs_endpoint = false; + match = true; mutex_unlock(&tv_tpg->tv_tpg_mutex); } + if (match) { + for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) { + vq = &vs->vqs[i]; + /* Flushing the vhost_work acts as synchronize_rcu */ + mutex_lock(&vq->mutex); + rcu_assign_pointer(vq->private_data, NULL); + mutex_unlock(&vq->mutex); + } + } + /* + * Act as synchronize_rcu to make sure access to + * old vs->vs_tpg is finished. + */ + vhost_scsi_flush(vs); + kfree(vs->vs_tpg); + vs->vs_tpg = NULL; mutex_unlock(&vs->dev.mutex); + return 0; err_tpg: @@ -899,6 +971,24 @@ err_dev: return ret; } +static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features) +{ + if (features & ~VHOST_SCSI_FEATURES) + return -EOPNOTSUPP; + + mutex_lock(&vs->dev.mutex); + if ((features & (1 << VHOST_F_LOG_ALL)) && + !vhost_log_access_ok(&vs->dev)) { + mutex_unlock(&vs->dev.mutex); + return -EFAULT; + } + vs->dev.acked_features = features; + smp_wmb(); + vhost_scsi_flush(vs); + mutex_unlock(&vs->dev.mutex); + return 0; +} + static int vhost_scsi_open(struct inode *inode, struct file *f) { struct vhost_scsi *s; @@ -939,38 +1029,6 @@ static int vhost_scsi_release(struct inode *inode, struct file *f) return 0; } -static void vhost_scsi_flush_vq(struct vhost_scsi *vs, int index) -{ - vhost_poll_flush(&vs->dev.vqs[index].poll); -} - -static void vhost_scsi_flush(struct vhost_scsi *vs) -{ - int i; - - for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) - vhost_scsi_flush_vq(vs, i); - vhost_work_flush(&vs->dev, &vs->vs_completion_work); -} - -static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features) -{ - if (features & ~VHOST_SCSI_FEATURES) - return -EOPNOTSUPP; - - mutex_lock(&vs->dev.mutex); - if ((features & (1 << VHOST_F_LOG_ALL)) && - !vhost_log_access_ok(&vs->dev)) { - mutex_unlock(&vs->dev.mutex); - return -EFAULT; - } - vs->dev.acked_features = features; - smp_wmb(); - vhost_scsi_flush(vs); - mutex_unlock(&vs->dev.mutex); - return 0; -} - static long vhost_scsi_ioctl(struct file *f, unsigned int ioctl, unsigned long arg) { |