scsi: ibmvfc: Define per-queue state/list locks

Define per-queue locks for protecting queue state and event pool sent/free
lists. The evt list lock is initially redundant but it allows the driver to
be modified in the follow-up patches to relax the queue locking around
submissions and completions.

Link: https://lore.kernel.org/r/20210106201835.1053593-4-tyreld@linux.ibm.com
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index 8de2a25..69a6401 100644 (file)
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -176,8 +176,9 @@ static void ibmvfc_trc_start(struct ibmvfc_event *evt)
        struct ibmvfc_mad_common *mad = &evt->iu.mad_common;
        struct ibmvfc_fcp_cmd_iu *iu = ibmvfc_get_fcp_iu(vhost, vfc_cmd);
        struct ibmvfc_trace_entry *entry;
+       int index = atomic_inc_return(&vhost->trace_index) & IBMVFC_TRACE_INDEX_MASK;
 
-       entry = &vhost->trace[vhost->trace_index++];
+       entry = &vhost->trace[index];
        entry->evt = evt;
        entry->time = jiffies;
        entry->fmt = evt->crq.format;
@@ -211,8 +212,10 @@ static void ibmvfc_trc_end(struct ibmvfc_event *evt)
        struct ibmvfc_mad_common *mad = &evt->xfer_iu->mad_common;
        struct ibmvfc_fcp_cmd_iu *iu = ibmvfc_get_fcp_iu(vhost, vfc_cmd);
        struct ibmvfc_fcp_rsp *rsp = ibmvfc_get_fcp_rsp(vhost, vfc_cmd);
-       struct ibmvfc_trace_entry *entry = &vhost->trace[vhost->trace_index++];
+       struct ibmvfc_trace_entry *entry;
+       int index = atomic_inc_return(&vhost->trace_index) & IBMVFC_TRACE_INDEX_MASK;
 
+       entry = &vhost->trace[index];
        entry->evt = evt;
        entry->time = jiffies;
        entry->fmt = evt->crq.format;
@@ -805,6 +808,7 @@ static int ibmvfc_reset_crq(struct ibmvfc_host *vhost)
        } while (rc == H_BUSY || H_IS_LONG_BUSY(rc));
 
        spin_lock_irqsave(vhost->host->host_lock, flags);
+       spin_lock(vhost->crq.q_lock);
        vhost->state = IBMVFC_NO_CRQ;
        vhost->logged_in = 0;
 
@@ -821,6 +825,7 @@ static int ibmvfc_reset_crq(struct ibmvfc_host *vhost)
                dev_warn(vhost->dev, "Partner adapter not ready\n");
        else if (rc != 0)
                dev_warn(vhost->dev, "Couldn't register crq (rc=%d)\n", rc);
+       spin_unlock(vhost->crq.q_lock);
        spin_unlock_irqrestore(vhost->host->host_lock, flags);
 
        return rc;
@@ -853,10 +858,16 @@ static int ibmvfc_valid_event(struct ibmvfc_event_pool *pool,
 static void ibmvfc_free_event(struct ibmvfc_event *evt)
 {
        struct ibmvfc_event_pool *pool = &evt->queue->evt_pool;
+       unsigned long flags;
 
        BUG_ON(!ibmvfc_valid_event(pool, evt));
        BUG_ON(atomic_inc_return(&evt->free) != 1);
+
+       spin_lock_irqsave(&evt->queue->l_lock, flags);
        list_add_tail(&evt->queue_list, &evt->queue->free);
+       if (evt->eh_comp)
+               complete(evt->eh_comp);
+       spin_unlock_irqrestore(&evt->queue->l_lock, flags);
 }
 
 /**
@@ -875,13 +886,28 @@ static void ibmvfc_scsi_eh_done(struct ibmvfc_event *evt)
                cmnd->scsi_done(cmnd);
        }
 
-       if (evt->eh_comp)
-               complete(evt->eh_comp);
-
        ibmvfc_free_event(evt);
 }
 
 /**
+ * ibmvfc_complete_purge - Complete failed command list
+ * @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.
+ **/
+static void ibmvfc_complete_purge(struct list_head *purge_list)
+{
+       struct ibmvfc_event *evt, *pos;
+
+       list_for_each_entry_safe(evt, pos, purge_list, queue_list) {
+               list_del(&evt->queue_list);
+               ibmvfc_trc_end(evt);
+               evt->done(evt);
+       }
+}
+
+/**
  * ibmvfc_fail_request - Fail request with specified error code
  * @evt:               ibmvfc event struct
  * @error_code:        error code to fail request with
@@ -897,10 +923,7 @@ static void ibmvfc_fail_request(struct ibmvfc_event *evt, int error_code)
        } else
                evt->xfer_iu->mad_common.status = cpu_to_be16(IBMVFC_MAD_DRIVER_FAILED);
 
-       list_del(&evt->queue_list);
        del_timer(&evt->timer);
-       ibmvfc_trc_end(evt);
-       evt->done(evt);
 }
 
 /**
@@ -914,10 +937,14 @@ static void ibmvfc_fail_request(struct ibmvfc_event *evt, int error_code)
 static void ibmvfc_purge_requests(struct ibmvfc_host *vhost, int error_code)
 {
        struct ibmvfc_event *evt, *pos;
+       unsigned long flags;
 
        ibmvfc_dbg(vhost, "Purging all requests\n");
+       spin_lock_irqsave(&vhost->crq.l_lock, flags);
        list_for_each_entry_safe(evt, pos, &vhost->crq.sent, queue_list)
                ibmvfc_fail_request(evt, error_code);
+       list_splice_init(&vhost->crq.sent, &vhost->purge);
+       spin_unlock_irqrestore(&vhost->crq.l_lock, flags);
 }
 
 /**
@@ -1314,6 +1341,7 @@ static int ibmvfc_init_event_pool(struct ibmvfc_host *vhost,
 
        INIT_LIST_HEAD(&queue->sent);
        INIT_LIST_HEAD(&queue->free);
+       spin_lock_init(&queue->l_lock);
 
        for (i = 0; i < pool->size; ++i) {
                struct ibmvfc_event *evt = &pool->events[i];
@@ -1368,11 +1396,14 @@ static void ibmvfc_free_event_pool(struct ibmvfc_host *vhost,
 static struct ibmvfc_event *ibmvfc_get_event(struct ibmvfc_queue *queue)
 {
        struct ibmvfc_event *evt;
+       unsigned long flags;
 
+       spin_lock_irqsave(&queue->l_lock, flags);
        BUG_ON(list_empty(&queue->free));
        evt = list_entry(queue->free.next, struct ibmvfc_event, queue_list);
        atomic_set(&evt->free, 0);
        list_del(&evt->queue_list);
+       spin_unlock_irqrestore(&queue->l_lock, flags);
        return evt;
 }
 
@@ -1506,6 +1537,7 @@ static int ibmvfc_send_event(struct ibmvfc_event *evt,
                             struct ibmvfc_host *vhost, unsigned long timeout)
 {
        __be64 *crq_as_u64 = (__be64 *) &evt->crq;
+       unsigned long flags;
        int rc;
 
        /* Copy the IU into the transfer area */
@@ -1517,7 +1549,6 @@ static int ibmvfc_send_event(struct ibmvfc_event *evt,
        else
                BUG();
 
-       list_add_tail(&evt->queue_list, &evt->queue->sent);
        timer_setup(&evt->timer, ibmvfc_timeout, 0);
 
        if (timeout) {
@@ -1525,11 +1556,15 @@ static int ibmvfc_send_event(struct ibmvfc_event *evt,
                add_timer(&evt->timer);
        }
 
+       spin_lock_irqsave(&evt->queue->l_lock, flags);
+       list_add_tail(&evt->queue_list, &evt->queue->sent);
+
        mb();
 
        if ((rc = ibmvfc_send_crq(vhost, be64_to_cpu(crq_as_u64[0]),
                                  be64_to_cpu(crq_as_u64[1])))) {
                list_del(&evt->queue_list);
+               spin_unlock_irqrestore(&evt->queue->l_lock, flags);
                del_timer(&evt->timer);
 
                /* If send_crq returns H_CLOSED, return SCSI_MLQUEUE_HOST_BUSY.
@@ -1554,8 +1589,10 @@ static int ibmvfc_send_event(struct ibmvfc_event *evt,
                        evt->xfer_iu->mad_common.status = cpu_to_be16(IBMVFC_MAD_CRQ_ERROR);
 
                evt->done(evt);
-       } else
+       } else {
+               spin_unlock_irqrestore(&evt->queue->l_lock, flags);
                ibmvfc_trc_start(evt);
+       }
 
        return 0;
 }
@@ -1663,9 +1700,6 @@ static void ibmvfc_scsi_done(struct ibmvfc_event *evt)
                cmnd->scsi_done(cmnd);
        }
 
-       if (evt->eh_comp)
-               complete(evt->eh_comp);
-
        ibmvfc_free_event(evt);
 }
 
@@ -2219,28 +2253,28 @@ static int ibmvfc_wait_for_ops(struct ibmvfc_host *vhost, void *device,
        ENTER;
        do {
                wait = 0;
-               spin_lock_irqsave(vhost->host->host_lock, flags);
+               spin_lock_irqsave(&vhost->crq.l_lock, flags);
                list_for_each_entry(evt, &vhost->crq.sent, queue_list) {
                        if (match(evt, device)) {
                                evt->eh_comp = &comp;
                                wait++;
                        }
                }
-               spin_unlock_irqrestore(vhost->host->host_lock, flags);
+               spin_unlock_irqrestore(&vhost->crq.l_lock, flags);
 
                if (wait) {
                        timeout = wait_for_completion_timeout(&comp, timeout);
 
                        if (!timeout) {
                                wait = 0;
-                               spin_lock_irqsave(vhost->host->host_lock, flags);
+                               spin_lock_irqsave(&vhost->crq.l_lock, flags);
                                list_for_each_entry(evt, &vhost->crq.sent, queue_list) {
                                        if (match(evt, device)) {
                                                evt->eh_comp = NULL;
                                                wait++;
                                        }
                                }
-                               spin_unlock_irqrestore(vhost->host->host_lock, flags);
+                               spin_unlock_irqrestore(&vhost->crq.l_lock, flags);
                                if (wait)
                                        dev_err(vhost->dev, "Timed out waiting for aborted commands\n");
                                LEAVE;
@@ -2277,14 +2311,16 @@ static int ibmvfc_cancel_all(struct scsi_device *sdev, int type)
        u16 status;
 
        ENTER;
-       spin_lock_irqsave(vhost->host->host_lock, flags);
        found_evt = NULL;
+       spin_lock_irqsave(vhost->host->host_lock, flags);
+       spin_lock(&vhost->crq.l_lock);
        list_for_each_entry(evt, &vhost->crq.sent, queue_list) {
                if (evt->cmnd && evt->cmnd->device == sdev) {
                        found_evt = evt;
                        break;
                }
        }
+       spin_unlock(&vhost->crq.l_lock);
 
        if (!found_evt) {
                if (vhost->log_level > IBMVFC_DEFAULT_LOG_LEVEL)
@@ -2414,14 +2450,16 @@ static int ibmvfc_abort_task_set(struct scsi_device *sdev)
        unsigned long flags, timeout = IBMVFC_ABORT_TIMEOUT;
        int rsp_code = 0;
 
-       spin_lock_irqsave(vhost->host->host_lock, flags);
        found_evt = NULL;
+       spin_lock_irqsave(vhost->host->host_lock, flags);
+       spin_lock(&vhost->crq.l_lock);
        list_for_each_entry(evt, &vhost->crq.sent, queue_list) {
                if (evt->cmnd && evt->cmnd->device == sdev) {
                        found_evt = evt;
                        break;
                }
        }
+       spin_unlock(&vhost->crq.l_lock);
 
        if (!found_evt) {
                if (vhost->log_level > IBMVFC_DEFAULT_LOG_LEVEL)
@@ -2935,7 +2973,9 @@ static void ibmvfc_handle_crq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost)
        }
 
        del_timer(&evt->timer);
+       spin_lock(&evt->queue->l_lock);
        list_del(&evt->queue_list);
+       spin_unlock(&evt->queue->l_lock);
        ibmvfc_trc_end(evt);
        evt->done(evt);
 }
@@ -3328,6 +3368,7 @@ static void ibmvfc_tasklet(void *data)
        int done = 0;
 
        spin_lock_irqsave(vhost->host->host_lock, flags);
+       spin_lock(vhost->crq.q_lock);
        while (!done) {
                /* Pull all the valid messages off the async CRQ */
                while ((async = ibmvfc_next_async_crq(vhost)) != NULL) {
@@ -3358,6 +3399,7 @@ static void ibmvfc_tasklet(void *data)
                        done = 1;
        }
 
+       spin_unlock(vhost->crq.q_lock);
        spin_unlock_irqrestore(vhost->host->host_lock, flags);
 }
 
@@ -4734,6 +4776,7 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost)
        struct ibmvfc_target *tgt;
        unsigned long flags;
        struct fc_rport *rport;
+       LIST_HEAD(purge);
        int rc;
 
        ibmvfc_log_ae(vhost, vhost->events_to_log);
@@ -4746,6 +4789,8 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost)
                break;
        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);
                rc = ibmvfc_reset_crq(vhost);
                spin_lock_irqsave(vhost->host->host_lock, flags);
@@ -4759,6 +4804,8 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost)
                break;
        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);
                rc = ibmvfc_reenable_crq_queue(vhost);
                spin_lock_irqsave(vhost->host->host_lock, flags);
@@ -4936,6 +4983,9 @@ static int ibmvfc_alloc_queue(struct ibmvfc_host *vhost,
        size_t fmt_size;
 
        ENTER;
+       spin_lock_init(&queue->_lock);
+       queue->q_lock = &queue->_lock;
+
        switch (fmt) {
        case IBMVFC_CRQ_FMT:
                fmt_size = sizeof(*queue->msgs.crq);
@@ -5098,6 +5148,7 @@ static int ibmvfc_alloc_mem(struct ibmvfc_host *vhost)
 
        vhost->trace = kcalloc(IBMVFC_NUM_TRACE_ENTRIES,
                               sizeof(struct ibmvfc_trace_entry), GFP_KERNEL);
+       atomic_set(&vhost->trace_index, -1);
 
        if (!vhost->trace)
                goto free_disc_buffer;
@@ -5214,6 +5265,7 @@ static int ibmvfc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 
        vhost = shost_priv(shost);
        INIT_LIST_HEAD(&vhost->targets);
+       INIT_LIST_HEAD(&vhost->purge);
        sprintf(vhost->name, IBMVFC_NAME);
        vhost->host = shost;
        vhost->dev = dev;
@@ -5298,6 +5350,7 @@ out:
 static int ibmvfc_remove(struct vio_dev *vdev)
 {
        struct ibmvfc_host *vhost = dev_get_drvdata(&vdev->dev);
+       LIST_HEAD(purge);
        unsigned long flags;
 
        ENTER;
@@ -5315,6 +5368,8 @@ 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_free_event_pool(vhost, &vhost->crq);
 

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.h b/drivers/scsi/ibmvscsi/ibmvfc.h
index 61c73b6..faf5b50 100644 (file)
--- a/drivers/scsi/ibmvscsi/ibmvfc.h
+++ b/drivers/scsi/ibmvscsi/ibmvfc.h
@@ -768,10 +768,13 @@ struct ibmvfc_queue {
        dma_addr_t msg_token;
        enum ibmvfc_msg_fmt fmt;
        int size, cur;
+       spinlock_t _lock;
+       spinlock_t *q_lock;
 
        struct ibmvfc_event_pool evt_pool;
        struct list_head sent;
        struct list_head free;
+       spinlock_t l_lock;
 };
 
 enum ibmvfc_host_action {
@@ -808,11 +811,13 @@ struct ibmvfc_host {
        enum ibmvfc_host_action action;
 #define IBMVFC_NUM_TRACE_INDEX_BITS            8
 #define IBMVFC_NUM_TRACE_ENTRIES               (1 << IBMVFC_NUM_TRACE_INDEX_BITS)
+#define IBMVFC_TRACE_INDEX_MASK                        (IBMVFC_NUM_TRACE_ENTRIES - 1)
 #define IBMVFC_TRACE_SIZE      (sizeof(struct ibmvfc_trace_entry) * IBMVFC_NUM_TRACE_ENTRIES)
        struct ibmvfc_trace_entry *trace;
-       u32 trace_index:IBMVFC_NUM_TRACE_INDEX_BITS;
+       atomic_t trace_index;
        int num_targets;
        struct list_head targets;
+       struct list_head purge;
        struct device *dev;
        struct dma_pool *sg_pool;
        mempool_t *tgt_pool;