This patch makes vhost_scsi_flush() wait for all the pending requests
issued before the flush operation to be finished.
Changes in v3:
- Rebase
- Drop 'tcm_vhost: Wait for pending requests in
vhost_scsi_clear_endpoint()' in this series, we already did that in
'tcm_vhost: Use vq->private_data to indicate if the endpoint is setup'
Changes in v2:
- Increase/Decrease inflight requests in
vhost_scsi_{allocate,free}_cmd and tcm_vhost_{allocate,free}_evt
Signed-off-by: Asias He <[email protected]>
---
drivers/vhost/tcm_vhost.c | 88 ++++++++++++++++++++++++++++++++++++++++++++---
drivers/vhost/tcm_vhost.h | 4 +++
2 files changed, 87 insertions(+), 5 deletions(-)
diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index 1f9116c..719ce13 100644
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -91,6 +91,15 @@ struct vhost_scsi {
struct mutex vs_events_lock; /* protect vs_events_dropped,events_nr */
bool vs_events_dropped; /* any missed events */
int vs_events_nr; /* num of pending events */
+
+ /*
+ * 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 */
@@ -108,6 +117,46 @@ 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;
@@ -402,6 +451,7 @@ 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)
{
mutex_lock(&vs->vs_events_lock);
+ tcm_vhost_dec_inflight(vs, evt->during_flush);
vs->vs_events_nr--;
kfree(evt);
mutex_unlock(&vs->vs_events_lock);
@@ -423,6 +473,7 @@ 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->vs_events_lock);
@@ -433,6 +484,7 @@ 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);
@@ -445,13 +497,16 @@ 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;
@@ -511,7 +566,7 @@ 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);
}
}
@@ -529,8 +584,8 @@ 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);
@@ -568,6 +623,7 @@ 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,
@@ -592,6 +648,8 @@ 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;
}
@@ -842,7 +900,7 @@ 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",
@@ -852,7 +910,6 @@ 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 !=
@@ -905,6 +962,7 @@ 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
@@ -984,9 +1042,23 @@ 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);
}
/*
@@ -1094,6 +1166,7 @@ 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])) {
@@ -1195,6 +1268,11 @@ static int vhost_scsi_open(struct inode *inode, struct
file *f)
s->vs_events_dropped = false;
mutex_init(&s->vs_events_lock);
+ 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;
for (i = VHOST_SCSI_VQ_IO; i < VHOST_SCSI_MAX_VQ; i++)
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
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