Asias He
2013-Mar-11 05:09 UTC
[PATCH 0/2] tcm_vhost: Wait for pending requests in flush and clear endpoint operation.
Asias He (2): tcm_vhost: Wait for pending requests in vhost_scsi_flush() tcm_vhost: Wait for pending requests in vhost_scsi_clear_endpoint() drivers/vhost/tcm_vhost.c | 119 +++++++++++++++++++++++++++++++++++++++------- drivers/vhost/tcm_vhost.h | 4 ++ 2 files changed, 105 insertions(+), 18 deletions(-) -- 1.8.1.4
Asias He
2013-Mar-11 05:09 UTC
[PATCH 1/2] tcm_vhost: Wait for pending requests in vhost_scsi_flush()
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 at redhat.com>
---
drivers/vhost/tcm_vhost.c | 115 ++++++++++++++++++++++++++++++++++++++--------
drivers/vhost/tcm_vhost.h | 4 ++
2 files changed, 101 insertions(+), 18 deletions(-)
diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index f80a545..5f8342c 100644
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -84,6 +84,15 @@ struct vhost_scsi {
bool vs_events_dropped; /* any missed events, protected by dev.mutex */
u64 vs_events_nr; /* # of pennding 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 */
@@ -101,6 +110,46 @@ 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;
@@ -433,9 +482,10 @@ static void vhost_scsi_free_cmd(struct tcm_vhost_cmd
*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;
@@ -493,13 +543,16 @@ static void tcm_vhost_evt_work(struct vhost_work *work)
vs_event_work);
struct tcm_vhost_evt *evt;
struct llist_node *llnode;
+ int during_flush;
llnode = llist_del_all(&vs->vs_event_list);
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);
+ during_flush = evt->during_flush;
tcm_vhost_free_evt(vs, evt);
+ tcm_vhost_dec_inflight(vs, during_flush);
}
}
@@ -516,8 +569,8 @@ 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;
+ int ret, vq, during_flush;
struct se_cmd *se_cmd;
- int ret, vq;
bitmap_zero(signal, VHOST_SCSI_MAX_VQ);
llnode = llist_del_all(&vs->vs_completion_list);
@@ -545,7 +598,9 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work
*work)
} else
pr_err("Faulted on virtio_scsi_cmd_resp\n");
+ during_flush = tv_cmd->during_flush;
vhost_scsi_free_cmd(tv_cmd);
+ tcm_vhost_dec_inflight(vs, during_flush);
}
vq = -1;
@@ -711,6 +766,7 @@ static void tcm_vhost_submission_work(struct work_struct
*work)
transport_send_check_condition_and_sense(se_cmd,
TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
transport_generic_free_cmd(se_cmd, 0);
+ tcm_vhost_dec_inflight(tv_cmd->tvc_vhost, tv_cmd->during_flush);
}
}
@@ -883,6 +939,9 @@ 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;
+
+ tv_cmd->during_flush = tcm_vhost_inc_inflight(vs);
+
/*
* Dispatch tv_cmd descriptor for cmwq execution in process
* context provided by tcm_vhost_workqueue. This also ensures
@@ -926,6 +985,8 @@ static int tcm_vhost_send_evt(struct vhost_scsi *vs, struct
tcm_vhost_tpg *tpg,
evt->event.lun[3] = lun->unpacked_lun & 0xFF;
}
+ evt->during_flush = tcm_vhost_inc_inflight(vs);
+
llist_add(&evt->list, &vs->vs_event_list);
vhost_work_queue(&vs->dev, &vs->vs_event_work);
@@ -952,6 +1013,34 @@ 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
@@ -1028,6 +1117,7 @@ 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])) {
@@ -1086,6 +1176,10 @@ 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;
@@ -1116,21 +1210,6 @@ 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
Asias He
2013-Mar-11 05:09 UTC
[PATCH 2/2] tcm_vhost: Wait for pending requests in vhost_scsi_clear_endpoint()
Wait for termination of all pending requests in clear endpoint operation, otherwise you cannot reset virtio devices safely. Signed-off-by: Asias He <asias at redhat.com> --- drivers/vhost/tcm_vhost.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c index 5f8342c..4b0cb12 100644 --- a/drivers/vhost/tcm_vhost.c +++ b/drivers/vhost/tcm_vhost.c @@ -1152,9 +1152,13 @@ static int vhost_scsi_clear_endpoint( tv_tpg->tv_tpg_vhost_count--; tv_tpg->vhost_scsi = NULL; vs->vs_tpg[target] = NULL; + /* After this, no further requests can be queued */ vs->vs_endpoint = false; mutex_unlock(&tv_tpg->tv_tpg_mutex); } + /* Flush the pending requests and wait for them to finish */ + vhost_scsi_flush(vs); + mutex_unlock(&vs->dev.mutex); return 0; -- 1.8.1.4