RDMA/hns: Use mutex instead of spinlock for ida allocation

GFP_KERNEL may cause ida_alloc_range() to sleep, but the spinlock covering
this function is not allowed to sleep, so the spinlock needs to be changed
to mutex.

As there is a certain chance of memory allocation failure, GFP_ATOMIC is
not suitable for QP allocation scenarios.

Fixes: 71586dd2 ("RDMA/hns: Create QP with selected QPN for bank load balance")
Link: https://lore.kernel.org/r/1611048513-28663-1-git-send-email-liweihang@huawei.comSigned-off-by: Yangyang Li <liyangyang20@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/hns/hns_roce_device.h

@@ -532,7 +532,7 @@ struct hns_roce_qp_table {
 	struct hns_roce_hem_table	sccc_table;
 	struct mutex			scc_mutex;
 	struct hns_roce_bank bank[HNS_ROCE_QP_BANK_NUM];
-	spinlock_t bank_lock;
+	struct mutex bank_mutex;
 };
 
 struct hns_roce_cq_table {

drivers/infiniband/hw/hns/hns_roce_qp.c

@@ -209,7 +209,7 @@ static int alloc_qpn(struct hns_roce_dev *hr_dev, struct hns_roce_qp *hr_qp)
 
 		hr_qp->doorbell_qpn = 1;
 	} else {
-		spin_lock(&qp_table->bank_lock);
+		mutex_lock(&qp_table->bank_mutex);
 		bankid = get_least_load_bankid_for_qp(qp_table->bank);
 
 		ret = alloc_qpn_with_bankid(&qp_table->bank[bankid], bankid,
@@ -217,12 +217,12 @@ static int alloc_qpn(struct hns_roce_dev *hr_dev, struct hns_roce_qp *hr_qp)
 		if (ret) {
 			ibdev_err(&hr_dev->ib_dev,
 				  "failed to alloc QPN, ret = %d\n", ret);
-			spin_unlock(&qp_table->bank_lock);
+			mutex_unlock(&qp_table->bank_mutex);
 			return ret;
 		}
 
 		qp_table->bank[bankid].inuse++;
-		spin_unlock(&qp_table->bank_lock);
+		mutex_unlock(&qp_table->bank_mutex);
 
 		hr_qp->doorbell_qpn = (u32)num;
 	}
@@ -408,9 +408,9 @@ static void free_qpn(struct hns_roce_dev *hr_dev, struct hns_roce_qp *hr_qp)
 
 	ida_free(&hr_dev->qp_table.bank[bankid].ida, hr_qp->qpn >> 3);
 
-	spin_lock(&hr_dev->qp_table.bank_lock);
+	mutex_lock(&hr_dev->qp_table.bank_mutex);
 	hr_dev->qp_table.bank[bankid].inuse--;
-	spin_unlock(&hr_dev->qp_table.bank_lock);
+	mutex_unlock(&hr_dev->qp_table.bank_mutex);
 }
 
 static int set_rq_size(struct hns_roce_dev *hr_dev, struct ib_qp_cap *cap,
@@ -1371,6 +1371,7 @@ int hns_roce_init_qp_table(struct hns_roce_dev *hr_dev)
 	unsigned int i;
 
 	mutex_init(&qp_table->scc_mutex);
+	mutex_init(&qp_table->bank_mutex);
 	xa_init(&hr_dev->qp_table_xa);
 
 	reserved_from_bot = hr_dev->caps.reserved_qps;