This patch makes vhost_scsi_flush() wait for all the pending requests issued before the flush operation to be finished. Signed-off-by: Asias He <asias@xxxxxxxxxx> --- drivers/vhost/tcm_vhost.c | 117 ++++++++++++++++++++++++++++++++++++++-------- drivers/vhost/tcm_vhost.h | 4 ++ 2 files changed, 101 insertions(+), 20 deletions(-) diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c index e734ead..dc0af52 100644 --- a/drivers/vhost/tcm_vhost.c +++ b/drivers/vhost/tcm_vhost.c @@ -82,6 +82,15 @@ struct vhost_scsi { bool vs_events_dropped; /* any missed events, protected by dev.mutex */ u64 vs_events_nr; /* num of pending events, protected by dev.mutex */ + + /* + * vs_inflight[0]/[1] are used to track requests issued + * before/during the flush operation + */ + u64 vs_inflight[2]; + wait_queue_head_t vs_flush_wait; /* wait queue for flush operation */ + spinlock_t vs_flush_lock; /* lock to protect vs_during_flush */ + int vs_during_flush; /* flag to indicate if we are in flush operation */ }; /* Local pointer to allocated TCM configfs fabric module */ @@ -99,6 +108,46 @@ static int iov_num_pages(struct iovec *iov) ((unsigned long)iov->iov_base & PAGE_MASK)) >> PAGE_SHIFT; } +static int tcm_vhost_inc_inflight(struct vhost_scsi *vs) +{ + int during_flush; + + spin_lock(&vs->vs_flush_lock); + during_flush = vs->vs_during_flush; + vs->vs_inflight[during_flush]++; + spin_unlock(&vs->vs_flush_lock); + + return during_flush; +} + +static void tcm_vhost_dec_inflight(struct vhost_scsi *vs, int during_flush) +{ + u64 inflight; + + spin_lock(&vs->vs_flush_lock); + inflight = vs->vs_inflight[during_flush]--; + /* + * Wakeup the waiter when all the requests issued before the flush + * operation are finished and we are during the flush operation. + */ + if (!inflight && !during_flush && vs->vs_during_flush) + wake_up(&vs->vs_flush_wait); + spin_unlock(&vs->vs_flush_lock); +} + +static bool tcm_vhost_done_inflight(struct vhost_scsi *vs) +{ + bool ret = false; + + /* The requests issued before the flush operation are finished ? */ + spin_lock(&vs->vs_flush_lock); + if (!vs->vs_inflight[0]) + ret = true; + spin_unlock(&vs->vs_flush_lock); + + return ret; +} + static bool tcm_vhost_check_feature(struct vhost_scsi *vs, int feature) { bool ret = false; @@ -391,6 +440,8 @@ static int tcm_vhost_queue_tm_rsp(struct se_cmd *se_cmd) static void tcm_vhost_free_evt(struct vhost_scsi *vs, struct tcm_vhost_evt *evt) { + + tcm_vhost_dec_inflight(vs, evt->during_flush); mutex_lock(&vs->dev.mutex); vs->vs_events_nr--; kfree(evt); @@ -412,6 +463,7 @@ static struct tcm_vhost_evt *tcm_vhost_allocate_evt(struct vhost_scsi *vs, if (evt) { evt->event.event = event; evt->event.reason = reason; + evt->during_flush = tcm_vhost_inc_inflight(vs); vs->vs_events_nr++; } mutex_unlock(&vs->dev.mutex); @@ -422,6 +474,7 @@ static struct tcm_vhost_evt *tcm_vhost_allocate_evt(struct vhost_scsi *vs, static void vhost_scsi_free_cmd(struct tcm_vhost_cmd *tv_cmd) { struct se_cmd *se_cmd = &tv_cmd->tvc_se_cmd; + struct vhost_scsi *vs = tv_cmd->tvc_vhost; /* TODO locking against target/backend threads? */ transport_generic_free_cmd(se_cmd, 1); @@ -434,13 +487,16 @@ static void vhost_scsi_free_cmd(struct tcm_vhost_cmd *tv_cmd) kfree(tv_cmd->tvc_sgl); } + tcm_vhost_dec_inflight(vs, tv_cmd->during_flush); + kfree(tv_cmd); } static void tcm_vhost_do_evt_work(struct vhost_scsi *vs, - struct virtio_scsi_event *event) + struct tcm_vhost_evt *evt) { struct vhost_virtqueue *vq = &vs->vqs[VHOST_SCSI_VQ_EVT]; + struct virtio_scsi_event *event = &evt->event; struct virtio_scsi_event __user *eventp; unsigned out, in; int head, ret; @@ -503,7 +559,7 @@ static void tcm_vhost_evt_work(struct vhost_work *work) while (llnode) { evt = llist_entry(llnode, struct tcm_vhost_evt, list); llnode = llist_next(llnode); - tcm_vhost_do_evt_work(vs, &evt->event); + tcm_vhost_do_evt_work(vs, evt); tcm_vhost_free_evt(vs, evt); } } @@ -521,8 +577,8 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work) struct virtio_scsi_cmd_resp v_rsp; struct tcm_vhost_cmd *tv_cmd; struct llist_node *llnode; - struct se_cmd *se_cmd; int ret, vq; + struct se_cmd *se_cmd; bitmap_zero(signal, VHOST_SCSI_MAX_VQ); llnode = llist_del_all(&vs->vs_completion_list); @@ -560,6 +616,7 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work) } static struct tcm_vhost_cmd *vhost_scsi_allocate_cmd( + struct vhost_scsi *vs, struct tcm_vhost_tpg *tv_tpg, struct virtio_scsi_cmd_req *v_req, u32 exp_data_len, @@ -584,6 +641,8 @@ static struct tcm_vhost_cmd *vhost_scsi_allocate_cmd( tv_cmd->tvc_exp_data_len = exp_data_len; tv_cmd->tvc_data_direction = data_direction; tv_cmd->tvc_nexus = tv_nexus; + tv_cmd->tvc_vhost = vs; + tv_cmd->during_flush = tcm_vhost_inc_inflight(vs); return tv_cmd; } @@ -824,7 +883,7 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs, for (i = 0; i < data_num; i++) exp_data_len += vq->iov[data_first + i].iov_len; - tv_cmd = vhost_scsi_allocate_cmd(tv_tpg, &v_req, + tv_cmd = vhost_scsi_allocate_cmd(vs, tv_tpg, &v_req, exp_data_len, data_direction); if (IS_ERR(tv_cmd)) { vq_err(vq, "vhost_scsi_allocate_cmd failed %ld\n", @@ -834,7 +893,6 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs, pr_debug("Allocated tv_cmd: %p exp_data_len: %d, data_direction" ": %d\n", tv_cmd, exp_data_len, data_direction); - tv_cmd->tvc_vhost = vs; tv_cmd->tvc_vq = vq; if (unlikely(vq->iov[out].iov_len != @@ -887,6 +945,7 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs, * tcm_vhost_queue_data_in() and tcm_vhost_queue_status() */ tv_cmd->tvc_vq_desc = head; + /* * Dispatch tv_cmd descriptor for cmwq execution in process * context provided by tcm_vhost_workqueue. This also ensures @@ -956,6 +1015,34 @@ 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; + + /* Flush operation is started */ + spin_lock(&vs->vs_flush_lock); + vs->vs_during_flush = 1; + spin_unlock(&vs->vs_flush_lock); + + for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) + vhost_scsi_flush_vq(vs, i); + vhost_work_flush(&vs->dev, &vs->vs_completion_work); + vhost_work_flush(&vs->dev, &vs->vs_event_work); + + /* Wait until all requests issued before the flush to be finished */ + wait_event(vs->vs_flush_wait, tcm_vhost_done_inflight(vs)); + + /* Flush operation is finished */ + spin_lock(&vs->vs_flush_lock); + vs->vs_during_flush = 0; + spin_unlock(&vs->vs_flush_lock); +} + /* * Called from vhost_scsi_ioctl() context to walk the list of available * tcm_vhost_tpg with an active struct tcm_vhost_nexus @@ -1042,6 +1129,7 @@ static int vhost_scsi_clear_endpoint( u8 target; mutex_lock(&vs->dev.mutex); + /* Verify that ring has been setup correctly. */ for (index = 0; index < vs->dev.nvqs; ++index) { if (!vhost_vq_access_ok(&vs->vqs[index])) { @@ -1109,6 +1197,10 @@ static int vhost_scsi_open(struct inode *inode, struct file *f) vhost_work_init(&s->vs_event_work, tcm_vhost_evt_work); s->vs_events_nr = 0; + s->vs_inflight[0] = 0; + s->vs_inflight[1] = 0; + spin_lock_init(&s->vs_flush_lock); + init_waitqueue_head(&s->vs_flush_wait); s->vqs[VHOST_SCSI_VQ_CTL].handle_kick = vhost_scsi_ctl_handle_kick; s->vqs[VHOST_SCSI_VQ_EVT].handle_kick = vhost_scsi_evt_handle_kick; @@ -1139,21 +1231,6 @@ 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); - vhost_work_flush(&vs->dev, &vs->vs_event_work); -} - static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features) { if (features & ~VHOST_SCSI_FEATURES) diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h index 94e9ee53..dd84622 100644 --- a/drivers/vhost/tcm_vhost.h +++ b/drivers/vhost/tcm_vhost.h @@ -37,6 +37,8 @@ struct tcm_vhost_cmd { unsigned char tvc_sense_buf[TRANSPORT_SENSE_BUFFER]; /* Completed commands list, serviced from vhost worker thread */ struct llist_node tvc_completion_list; + /* Indicate this command is issued during the flush operaton */ + int during_flush; }; struct tcm_vhost_nexus { @@ -91,6 +93,8 @@ struct tcm_vhost_evt { struct virtio_scsi_event event; /* virtio_scsi event list, serviced from vhost worker thread */ struct llist_node list; + /* Indicate this event is issued during the flush operaton */ + int during_flush; }; /* -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html