nvmet-rdma: use a private workqueue for delete

[platform/kernel/linux-rpi.git] / drivers / nvme / target / rdma.c

diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index 3533e91..5becca8 100644 (file)
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -66,6 +66,7 @@ struct nvmet_rdma_rsp {
 
        struct nvmet_req        req;
 
+       bool                    allocated;
        u8                      n_rdma;
        u32                     flags;
        u32                     invalidate_rkey;
@@ -121,6 +122,7 @@ struct nvmet_rdma_device {
        int                     inline_page_count;
 };
 
+struct workqueue_struct *nvmet_rdma_delete_wq;
 static bool nvmet_rdma_use_srq;
 module_param_named(use_srq, nvmet_rdma_use_srq, bool, 0444);
 MODULE_PARM_DESC(use_srq, "Use shared receive queue.");
@@ -174,11 +176,19 @@ nvmet_rdma_get_rsp(struct nvmet_rdma_queue *queue)
        unsigned long flags;
 
        spin_lock_irqsave(&queue->rsps_lock, flags);
-       rsp = list_first_entry(&queue->free_rsps,
+       rsp = list_first_entry_or_null(&queue->free_rsps,
                                struct nvmet_rdma_rsp, free_list);
-       list_del(&rsp->free_list);
+       if (likely(rsp))
+               list_del(&rsp->free_list);
        spin_unlock_irqrestore(&queue->rsps_lock, flags);
 
+       if (unlikely(!rsp)) {
+               rsp = kmalloc(sizeof(*rsp), GFP_KERNEL);
+               if (unlikely(!rsp))
+                       return NULL;
+               rsp->allocated = true;
+       }
+
        return rsp;
 }
 
@@ -187,6 +197,11 @@ nvmet_rdma_put_rsp(struct nvmet_rdma_rsp *rsp)
 {
        unsigned long flags;
 
+       if (rsp->allocated) {
+               kfree(rsp);
+               return;
+       }
+
        spin_lock_irqsave(&rsp->queue->rsps_lock, flags);
        list_add_tail(&rsp->free_list, &rsp->queue->free_rsps);
        spin_unlock_irqrestore(&rsp->queue->rsps_lock, flags);
@@ -776,6 +791,15 @@ static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
 
        cmd->queue = queue;
        rsp = nvmet_rdma_get_rsp(queue);
+       if (unlikely(!rsp)) {
+               /*
+                * we get here only under memory pressure,
+                * silently drop and have the host retry
+                * as we can't even fail it.
+                */
+               nvmet_rdma_post_recv(queue->dev, cmd);
+               return;
+       }
        rsp->queue = queue;
        rsp->cmd = cmd;
        rsp->flags = 0;
@@ -1244,12 +1268,12 @@ static int nvmet_rdma_queue_connect(struct rdma_cm_id *cm_id,
 
        if (queue->host_qid == 0) {
                /* Let inflight controller teardown complete */
-               flush_scheduled_work();
+               flush_workqueue(nvmet_rdma_delete_wq);
        }
 
        ret = nvmet_rdma_cm_accept(cm_id, queue, &event->param.conn);
        if (ret) {
-               schedule_work(&queue->release_work);
+               queue_work(nvmet_rdma_delete_wq, &queue->release_work);
                /* Destroying rdma_cm id is not needed here */
                return 0;
        }
@@ -1314,7 +1338,7 @@ static void __nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
 
        if (disconnect) {
                rdma_disconnect(queue->cm_id);
-               schedule_work(&queue->release_work);
+               queue_work(nvmet_rdma_delete_wq, &queue->release_work);
        }
 }
 
@@ -1344,7 +1368,7 @@ static void nvmet_rdma_queue_connect_fail(struct rdma_cm_id *cm_id,
        mutex_unlock(&nvmet_rdma_queue_mutex);
 
        pr_err("failed to connect queue %d\n", queue->idx);
-       schedule_work(&queue->release_work);
+       queue_work(nvmet_rdma_delete_wq, &queue->release_work);
 }
 
 /**
@@ -1626,8 +1650,17 @@ static int __init nvmet_rdma_init(void)
        if (ret)
                goto err_ib_client;
 
+       nvmet_rdma_delete_wq = alloc_workqueue("nvmet-rdma-delete-wq",
+                       WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS, 0);
+       if (!nvmet_rdma_delete_wq) {
+               ret = -ENOMEM;
+               goto err_unreg_transport;
+       }
+
        return 0;
 
+err_unreg_transport:
+       nvmet_unregister_transport(&nvmet_rdma_ops);
 err_ib_client:
        ib_unregister_client(&nvmet_rdma_ib_client);
        return ret;
@@ -1635,6 +1668,7 @@ err_ib_client:
 
 static void __exit nvmet_rdma_exit(void)
 {
+       destroy_workqueue(nvmet_rdma_delete_wq);
        nvmet_unregister_transport(&nvmet_rdma_ops);
        ib_unregister_client(&nvmet_rdma_ib_client);
        WARN_ON_ONCE(!list_empty(&nvmet_rdma_queue_list));