RDMA/bnxt_re: Protect the PD table bitmap

Syncrhonization is required to avoid simultaneous allocation
of the PD. Add a new mutex lock to handle allocation from
the PD table.

Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Link: https://lore.kernel.org/r/1692032419-21680-2-git-send-email-selvin.xavier@broadcom.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>

Author: selvintxavier

drivers/infiniband/hw/bnxt_re/ib_verbs.c

@@ -619,7 +619,7 @@ int bnxt_re_alloc_pd(struct ib_pd *ibpd, struct ib_udata *udata)
 	int rc = 0;
 
 	pd->rdev = rdev;
-	if (bnxt_qplib_alloc_pd(&rdev->qplib_res.pd_tbl, &pd->qplib_pd)) {
+	if (bnxt_qplib_alloc_pd(&rdev->qplib_res, &pd->qplib_pd)) {
 		ibdev_err(&rdev->ibdev, "Failed to allocate HW PD");
 		rc = -ENOMEM;
 		goto fail;

drivers/infiniband/hw/bnxt_re/qplib_res.c

@@ -642,31 +642,44 @@ static void bnxt_qplib_init_sgid_tbl(struct bnxt_qplib_sgid_tbl *sgid_tbl,
 }
 
 /* PDs */
-int bnxt_qplib_alloc_pd(struct bnxt_qplib_pd_tbl *pdt, struct bnxt_qplib_pd *pd)
+int bnxt_qplib_alloc_pd(struct bnxt_qplib_res  *res, struct bnxt_qplib_pd *pd)
 {
+	struct bnxt_qplib_pd_tbl *pdt = &res->pd_tbl;
 	u32 bit_num;
+	int rc = 0;
 
+	mutex_lock(&res->pd_tbl_lock);
 	bit_num = find_first_bit(pdt->tbl, pdt->max);
-	if (bit_num == pdt->max)
-		return -ENOMEM;
+	if (bit_num == pdt->max) {
+		rc = -ENOMEM;
+		goto exit;
+	}
 
 	/* Found unused PD */
 	clear_bit(bit_num, pdt->tbl);
 	pd->id = bit_num;
-	return 0;
+exit:
+	mutex_unlock(&res->pd_tbl_lock);
+	return rc;
 }
 
 int bnxt_qplib_dealloc_pd(struct bnxt_qplib_res *res,
 			  struct bnxt_qplib_pd_tbl *pdt,
 			  struct bnxt_qplib_pd *pd)
 {
+	int rc = 0;
+
+	mutex_lock(&res->pd_tbl_lock);
 	if (test_and_set_bit(pd->id, pdt->tbl)) {
 		dev_warn(&res->pdev->dev, "Freeing an unused PD? pdn = %d\n",
 			 pd->id);
-		return -EINVAL;
+		rc = -EINVAL;
+		goto exit;
 	}
 	pd->id = 0;
-	return 0;
+exit:
+	mutex_unlock(&res->pd_tbl_lock);
+	return rc;
 }
 
 static void bnxt_qplib_free_pd_tbl(struct bnxt_qplib_pd_tbl *pdt)
@@ -691,6 +704,7 @@ static int bnxt_qplib_alloc_pd_tbl(struct bnxt_qplib_res *res,
 
 	pdt->max = max;
 	memset((u8 *)pdt->tbl, 0xFF, bytes);
+	mutex_init(&res->pd_tbl_lock);
 
 	return 0;
 }

drivers/infiniband/hw/bnxt_re/qplib_res.h

@@ -277,6 +277,8 @@ struct bnxt_qplib_res {
 	struct net_device		*netdev;
 	struct bnxt_qplib_rcfw		*rcfw;
 	struct bnxt_qplib_pd_tbl	pd_tbl;
+	/* To protect the pd table bit map */
+	struct mutex			pd_tbl_lock;
 	struct bnxt_qplib_sgid_tbl	sgid_tbl;
 	struct bnxt_qplib_dpi_tbl	dpi_tbl;
 	/* To protect the dpi table bit map */
@@ -368,7 +370,7 @@ void bnxt_qplib_free_hwq(struct bnxt_qplib_res *res,
 			 struct bnxt_qplib_hwq *hwq);
 int bnxt_qplib_alloc_init_hwq(struct bnxt_qplib_hwq *hwq,
 			      struct bnxt_qplib_hwq_attr *hwq_attr);
-int bnxt_qplib_alloc_pd(struct bnxt_qplib_pd_tbl *pd_tbl,
+int bnxt_qplib_alloc_pd(struct bnxt_qplib_res *res,
 			struct bnxt_qplib_pd *pd);
 int bnxt_qplib_dealloc_pd(struct bnxt_qplib_res *res,
 			  struct bnxt_qplib_pd_tbl *pd_tbl,