[PATCH v2 4/5] ibmvfc: complete commands outside the host/queue lock

Tyrel Datwyler
2021-01-04T22:25:35Z

Drain the command queue and place all commands on a completion list.
Perform command completion on that list outside the host/queue locks.
Further, move purged command compeletions outside the host_lock as well.

Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
---

Changes in v2:
* Changed ibmvfc_locked_done to static fixing no-prototype warning

drivers/scsi/ibmvscsi/ibmvfc.c | 58 ++++++++++++++++++++++++++--------
drivers/scsi/ibmvscsi/ibmvfc.h | 3 +-
2 files changed, 47 insertions(+), 14 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index 69a6401ca504..f680f96d5d06 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -894,7 +894,7 @@ static void ibmvfc_scsi_eh_done(struct ibmvfc_event *evt)
* @purge_list: list head of failed commands
*
* This function runs completions on commands to fail as a result of a
- * host reset or platform migration. Caller must hold host_lock.
+ * host reset or platform migration.
**/
static void ibmvfc_complete_purge(struct list_head *purge_list)
{
@@ -1407,6 +1407,23 @@ static struct ibmvfc_event *ibmvfc_get_event(struct ibmvfc_queue *queue)
return evt;
}

+/**
+ * ibmvfc_locked_done - Calls evt completion with host_lock held
+ * @evt: ibmvfc evt to complete
+ *
+ * All non-scsi command completion callbacks have the expectation that the
+ * host_lock is held. This callback is used by ibmvfc_init_event to wrap a
+ * MAD evt with the host_lock.
+ **/
+static void ibmvfc_locked_done(struct ibmvfc_event *evt)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(evt->vhost->host->host_lock, flags);
+ evt->_done(evt);
+ spin_unlock_irqrestore(evt->vhost->host->host_lock, flags);
+}
+
/**
* ibmvfc_init_event - Initialize fields in an event struct that are always
* required.
@@ -1419,9 +1436,14 @@ static void ibmvfc_init_event(struct ibmvfc_event *evt,
{
evt->cmnd = NULL;
evt->sync_iu = NULL;
- evt->crq.format = format;
- evt->done = done;
evt->eh_comp = NULL;
+ evt->crq.format = format;
+ if (format == IBMVFC_CMD_FORMAT)
+ evt->done = done;
+ else {
+ evt->_done = done;
+ evt->done = ibmvfc_locked_done;
+ }
}

/**
@@ -1640,7 +1662,9 @@ static void ibmvfc_relogin(struct scsi_device *sdev)
struct ibmvfc_host *vhost = shost_priv(sdev->host);
struct fc_rport *rport = starget_to_rport(scsi_target(sdev));
struct ibmvfc_target *tgt;
+ unsigned long flags;

+ spin_lock_irqsave(vhost->host->host_lock, flags);
list_for_each_entry(tgt, &vhost->targets, queue) {
if (rport == tgt->rport) {
ibmvfc_del_tgt(tgt);
@@ -1649,6 +1673,7 @@ static void ibmvfc_relogin(struct scsi_device *sdev)
}

ibmvfc_reinit_host(vhost);
+ spin_unlock_irqrestore(vhost->host->host_lock, flags);
}

/**
@@ -2901,7 +2926,8 @@ static void ibmvfc_handle_async(struct ibmvfc_async_crq *crq,
* @vhost: ibmvfc host struct
*
**/
-static void ibmvfc_handle_crq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost)
+static void ibmvfc_handle_crq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost,
+ struct list_head *evt_doneq)
{
long rc;
struct ibmvfc_event *evt = (struct ibmvfc_event *)be64_to_cpu(crq->ioba);
@@ -2972,12 +2998,9 @@ static void ibmvfc_handle_crq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost)
return;
}

- del_timer(&evt->timer);
spin_lock(&evt->queue->l_lock);
- list_del(&evt->queue_list);
+ list_move_tail(&evt->queue_list, evt_doneq);
spin_unlock(&evt->queue->l_lock);
- ibmvfc_trc_end(evt);
- evt->done(evt);
}

/**
@@ -3364,8 +3387,10 @@ static void ibmvfc_tasklet(void *data)
struct vio_dev *vdev = to_vio_dev(vhost->dev);
struct ibmvfc_crq *crq;
struct ibmvfc_async_crq *async;
+ struct ibmvfc_event *evt, *temp;
unsigned long flags;
int done = 0;
+ LIST_HEAD(evt_doneq);

spin_lock_irqsave(vhost->host->host_lock, flags);
spin_lock(vhost->crq.q_lock);
@@ -3379,7 +3404,7 @@ static void ibmvfc_tasklet(void *data)

/* Pull all the valid messages off the CRQ */
while ((crq = ibmvfc_next_crq(vhost)) != NULL) {
- ibmvfc_handle_crq(crq, vhost);
+ ibmvfc_handle_crq(crq, vhost, &evt_doneq);
crq->valid = 0;
wmb();
}
@@ -3392,7 +3417,7 @@ static void ibmvfc_tasklet(void *data)
wmb();
} else if ((crq = ibmvfc_next_crq(vhost)) != NULL) {
vio_disable_interrupts(vdev);
- ibmvfc_handle_crq(crq, vhost);
+ ibmvfc_handle_crq(crq, vhost, &evt_doneq);
crq->valid = 0;
wmb();
} else
@@ -3401,6 +3426,13 @@ static void ibmvfc_tasklet(void *data)

spin_unlock(vhost->crq.q_lock);
spin_unlock_irqrestore(vhost->host->host_lock, flags);
+
+ list_for_each_entry_safe(evt, temp, &evt_doneq, queue_list) {
+ del_timer(&evt->timer);
+ list_del(&evt->queue_list);
+ ibmvfc_trc_end(evt);
+ evt->done(evt);
+ }
}

/**
@@ -4790,8 +4822,8 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost)
case IBMVFC_HOST_ACTION_RESET:
vhost->action = IBMVFC_HOST_ACTION_TGT_DEL;
list_splice_init(&vhost->purge, &purge);
- ibmvfc_complete_purge(&purge);
spin_unlock_irqrestore(vhost->host->host_lock, flags);
+ ibmvfc_complete_purge(&purge);
rc = ibmvfc_reset_crq(vhost);
spin_lock_irqsave(vhost->host->host_lock, flags);
if (rc == H_CLOSED)
@@ -4805,8 +4837,8 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost)
case IBMVFC_HOST_ACTION_REENABLE:
vhost->action = IBMVFC_HOST_ACTION_TGT_DEL;
list_splice_init(&vhost->purge, &purge);
- ibmvfc_complete_purge(&purge);
spin_unlock_irqrestore(vhost->host->host_lock, flags);
+ ibmvfc_complete_purge(&purge);
rc = ibmvfc_reenable_crq_queue(vhost);
spin_lock_irqsave(vhost->host->host_lock, flags);
if (rc || (rc = ibmvfc_send_crq_init(vhost))) {
@@ -5369,8 +5401,8 @@ static int ibmvfc_remove(struct vio_dev *vdev)
spin_lock_irqsave(vhost->host->host_lock, flags);
ibmvfc_purge_requests(vhost, DID_ERROR);
list_splice_init(&vhost->purge, &purge);
- ibmvfc_complete_purge(&purge);
spin_unlock_irqrestore(vhost->host->host_lock, flags);
+ ibmvfc_complete_purge(&purge);
ibmvfc_free_event_pool(vhost, &vhost->crq);

ibmvfc_free_mem(vhost);
diff --git a/drivers/scsi/ibmvscsi/ibmvfc.h b/drivers/scsi/ibmvscsi/ibmvfc.h
index faf5b50d65b9..632e977449c5 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.h
+++ b/drivers/scsi/ibmvscsi/ibmvfc.h
@@ -733,7 +733,8 @@ struct ibmvfc_event {
struct scsi_cmnd *cmnd;
atomic_t free;
union ibmvfc_iu *xfer_iu;
- void (*done) (struct ibmvfc_event *);
+ void (*done)(struct ibmvfc_event *evt);
+ void (*_done)(struct ibmvfc_event *evt);
struct ibmvfc_crq crq;
union ibmvfc_iu iu;
union ibmvfc_iu *sync_iu;
--
2.27.0