iser-target: Allocate PI contexts dynamically

This patch converts to allocate PI contexts dynamically in order
avoid a potentially bogus np->tpg_np and associated NULL pointer
dereference in isert_connect_request() during iser-target endpoint
shutdown with multiple network portals.

Also, there is really no need to allocate these at connection
establishment since it is not guaranteed that all the IOs on
that connection will be to a PI formatted device.

We can do it in a lazy fashion so the initial burst will have a
transient slow down, but very fast all IOs will allocate a PI
context.

Squashed:

iser-target: Centralize PI context handling code

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

2 files changed, 158 insertions, 116 deletions

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 33b549e..b0e58f1 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -96,8 +96,7 @@ isert_query_device(struct ib_device *ib_dev, struct ib_device_attr *devattr)
 }
 
 static int
-isert_conn_setup_qp(struct isert_conn *isert_conn, struct rdma_cm_id *cma_id,
-		    u8 protection)
+isert_conn_setup_qp(struct isert_conn *isert_conn, struct rdma_cm_id *cma_id)
 {
 	struct isert_device *device = isert_conn->conn_device;
 	struct ib_qp_init_attr attr;
@@ -132,7 +131,7 @@ isert_conn_setup_qp(struct isert_conn *isert_conn, struct rdma_cm_id *cma_id,
 	attr.cap.max_recv_sge = 1;
 	attr.sq_sig_type = IB_SIGNAL_REQ_WR;
 	attr.qp_type = IB_QPT_RC;
-	if (protection)
+	if (device->pi_capable)
 		attr.create_flags |= IB_QP_CREATE_SIGNATURE_EN;
 
 	pr_debug("isert_conn_setup_qp cma_id->device: %p\n",
@@ -442,8 +441,68 @@ isert_conn_free_fastreg_pool(struct isert_conn *isert_conn)
 }
 
 static int
+isert_create_pi_ctx(struct fast_reg_descriptor *desc,
+		    struct ib_device *device,
+		    struct ib_pd *pd)
+{
+	struct ib_mr_init_attr mr_init_attr;
+	struct pi_context *pi_ctx;
+	int ret;
+
+	pi_ctx = kzalloc(sizeof(*desc->pi_ctx), GFP_KERNEL);
+	if (!pi_ctx) {
+		pr_err("Failed to allocate pi context\n");
+		return -ENOMEM;
+	}
+
+	pi_ctx->prot_frpl = ib_alloc_fast_reg_page_list(device,
+					    ISCSI_ISER_SG_TABLESIZE);
+	if (IS_ERR(pi_ctx->prot_frpl)) {
+		pr_err("Failed to allocate prot frpl err=%ld\n",
+			  PTR_ERR(pi_ctx->prot_frpl));
+		ret = PTR_ERR(pi_ctx->prot_frpl);
+		goto err_pi_ctx;
+	}
+
+	pi_ctx->prot_mr = ib_alloc_fast_reg_mr(pd, ISCSI_ISER_SG_TABLESIZE);
+	if (IS_ERR(pi_ctx->prot_mr)) {
+		pr_err("Failed to allocate prot frmr err=%ld\n",
+			  PTR_ERR(pi_ctx->prot_mr));
+		ret = PTR_ERR(pi_ctx->prot_mr);
+		goto err_prot_frpl;
+	}
+	desc->ind |= ISERT_PROT_KEY_VALID;
+
+	memset(&mr_init_attr, 0, sizeof(mr_init_attr));
+	mr_init_attr.max_reg_descriptors = 2;
+	mr_init_attr.flags |= IB_MR_SIGNATURE_EN;
+	pi_ctx->sig_mr = ib_create_mr(pd, &mr_init_attr);
+	if (IS_ERR(pi_ctx->sig_mr)) {
+		pr_err("Failed to allocate signature enabled mr err=%ld\n",
+			  PTR_ERR(pi_ctx->sig_mr));
+		ret = PTR_ERR(pi_ctx->sig_mr);
+		goto err_prot_mr;
+	}
+
+	desc->pi_ctx = pi_ctx;
+	desc->ind |= ISERT_SIG_KEY_VALID;
+	desc->ind &= ~ISERT_PROTECTED;
+
+	return 0;
+
+err_prot_mr:
+	ib_dereg_mr(desc->pi_ctx->prot_mr);
+err_prot_frpl:
+	ib_free_fast_reg_page_list(desc->pi_ctx->prot_frpl);
+err_pi_ctx:
+	kfree(desc->pi_ctx);
+
+	return ret;
+}
+
+static int
 isert_create_fr_desc(struct ib_device *ib_device, struct ib_pd *pd,
-		     struct fast_reg_descriptor *fr_desc, u8 protection)
+		     struct fast_reg_descriptor *fr_desc)
 {
 	int ret;
 
@@ -462,62 +521,12 @@ isert_create_fr_desc(struct ib_device *ib_device, struct ib_pd *pd,
 		ret = PTR_ERR(fr_desc->data_mr);
 		goto err_data_frpl;
 	}
-	pr_debug("Create fr_desc %p page_list %p\n",
-		 fr_desc, fr_desc->data_frpl->page_list);
 	fr_desc->ind |= ISERT_DATA_KEY_VALID;
 
-	if (protection) {
-		struct ib_mr_init_attr mr_init_attr = {0};
-		struct pi_context *pi_ctx;
-
-		fr_desc->pi_ctx = kzalloc(sizeof(*fr_desc->pi_ctx), GFP_KERNEL);
-		if (!fr_desc->pi_ctx) {
-			pr_err("Failed to allocate pi context\n");
-			ret = -ENOMEM;
-			goto err_data_mr;
-		}
-		pi_ctx = fr_desc->pi_ctx;
-
-		pi_ctx->prot_frpl = ib_alloc_fast_reg_page_list(ib_device,
-						    ISCSI_ISER_SG_TABLESIZE);
-		if (IS_ERR(pi_ctx->prot_frpl)) {
-			pr_err("Failed to allocate prot frpl err=%ld\n",
-			       PTR_ERR(pi_ctx->prot_frpl));
-			ret = PTR_ERR(pi_ctx->prot_frpl);
-			goto err_pi_ctx;
-		}
-
-		pi_ctx->prot_mr = ib_alloc_fast_reg_mr(pd, ISCSI_ISER_SG_TABLESIZE);
-		if (IS_ERR(pi_ctx->prot_mr)) {
-			pr_err("Failed to allocate prot frmr err=%ld\n",
-			       PTR_ERR(pi_ctx->prot_mr));
-			ret = PTR_ERR(pi_ctx->prot_mr);
-			goto err_prot_frpl;
-		}
-		fr_desc->ind |= ISERT_PROT_KEY_VALID;
-
-		mr_init_attr.max_reg_descriptors = 2;
-		mr_init_attr.flags |= IB_MR_SIGNATURE_EN;
-		pi_ctx->sig_mr = ib_create_mr(pd, &mr_init_attr);
-		if (IS_ERR(pi_ctx->sig_mr)) {
-			pr_err("Failed to allocate signature enabled mr err=%ld\n",
-			       PTR_ERR(pi_ctx->sig_mr));
-			ret = PTR_ERR(pi_ctx->sig_mr);
-			goto err_prot_mr;
-		}
-		fr_desc->ind |= ISERT_SIG_KEY_VALID;
-	}
-	fr_desc->ind &= ~ISERT_PROTECTED;
+	pr_debug("Created fr_desc %p\n", fr_desc);
 
 	return 0;
-err_prot_mr:
-	ib_dereg_mr(fr_desc->pi_ctx->prot_mr);
-err_prot_frpl:
-	ib_free_fast_reg_page_list(fr_desc->pi_ctx->prot_frpl);
-err_pi_ctx:
-	kfree(fr_desc->pi_ctx);
-err_data_mr:
-	ib_dereg_mr(fr_desc->data_mr);
+
 err_data_frpl:
 	ib_free_fast_reg_page_list(fr_desc->data_frpl);
 
@@ -525,7 +534,7 @@ err_data_frpl:
 }
 
 static int
-isert_conn_create_fastreg_pool(struct isert_conn *isert_conn, u8 pi_support)
+isert_conn_create_fastreg_pool(struct isert_conn *isert_conn)
 {
 	struct fast_reg_descriptor *fr_desc;
 	struct isert_device *device = isert_conn->conn_device;
@@ -549,8 +558,7 @@ isert_conn_create_fastreg_pool(struct isert_conn *isert_conn, u8 pi_support)
 		}
 
 		ret = isert_create_fr_desc(device->ib_device,
-					   isert_conn->conn_pd, fr_desc,
-					   pi_support);
+					   isert_conn->conn_pd, fr_desc);
 		if (ret) {
 			pr_err("Failed to create fastreg descriptor err=%d\n",
 			       ret);
@@ -581,7 +589,6 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
 	struct isert_device *device;
 	struct ib_device *ib_dev = cma_id->device;
 	int ret = 0;
-	u8 pi_support;
 
 	spin_lock_bh(&np->np_thread_lock);
 	if (!np->enabled) {
@@ -681,15 +688,7 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
 		goto out_mr;
 	}
 
-	pi_support = np->tpg_np->tpg->tpg_attrib.t10_pi;
-	if (pi_support && !device->pi_capable) {
-		pr_err("Protection information requested but not supported, "
-		       "rejecting connect request\n");
-		ret = rdma_reject(cma_id, NULL, 0);
-		goto out_mr;
-	}
-
-	ret = isert_conn_setup_qp(isert_conn, cma_id, pi_support);
+	ret = isert_conn_setup_qp(isert_conn, cma_id);
 	if (ret)
 		goto out_conn_dev;
 
@@ -1151,11 +1150,7 @@ isert_put_login_tx(struct iscsi_conn *conn, struct iscsi_login *login,
 		if (login->login_complete) {
 			if (!conn->sess->sess_ops->SessionType &&
 			    isert_conn->conn_device->use_fastreg) {
-				/* Normal Session and fastreg is used */
-				u8 pi_support = login->np->tpg_np->tpg->tpg_attrib.t10_pi;
-
-				ret = isert_conn_create_fastreg_pool(isert_conn,
-								     pi_support);
+				ret = isert_conn_create_fastreg_pool(isert_conn);
 				if (ret) {
 					pr_err("Conn: %p failed to create"
 					       " fastreg pool\n", isert_conn);
@@ -2771,10 +2766,10 @@ isert_set_prot_checks(u8 prot_checks)
 }
 
 static int
-isert_reg_sig_mr(struct isert_conn *isert_conn, struct se_cmd *se_cmd,
-		 struct fast_reg_descriptor *fr_desc,
-		 struct ib_sge *data_sge, struct ib_sge *prot_sge,
-		 struct ib_sge *sig_sge)
+isert_reg_sig_mr(struct isert_conn *isert_conn,
+		 struct se_cmd *se_cmd,
+		 struct isert_rdma_wr *rdma_wr,
+		 struct fast_reg_descriptor *fr_desc)
 {
 	struct ib_send_wr sig_wr, inv_wr;
 	struct ib_send_wr *bad_wr, *wr = NULL;
@@ -2804,13 +2799,13 @@ isert_reg_sig_mr(struct isert_conn *isert_conn, struct se_cmd *se_cmd,
 	memset(&sig_wr, 0, sizeof(sig_wr));
 	sig_wr.opcode = IB_WR_REG_SIG_MR;
 	sig_wr.wr_id = ISER_FASTREG_LI_WRID;
-	sig_wr.sg_list = data_sge;
+	sig_wr.sg_list = &rdma_wr->ib_sg[DATA];
 	sig_wr.num_sge = 1;
 	sig_wr.wr.sig_handover.access_flags = IB_ACCESS_LOCAL_WRITE;
 	sig_wr.wr.sig_handover.sig_attrs = &sig_attrs;
 	sig_wr.wr.sig_handover.sig_mr = pi_ctx->sig_mr;
 	if (se_cmd->t_prot_sg)
-		sig_wr.wr.sig_handover.prot = prot_sge;
+		sig_wr.wr.sig_handover.prot = &rdma_wr->ib_sg[PROT];
 
 	if (!wr)
 		wr = &sig_wr;
@@ -2824,34 +2819,93 @@ isert_reg_sig_mr(struct isert_conn *isert_conn, struct se_cmd *se_cmd,
 	}
 	fr_desc->ind &= ~ISERT_SIG_KEY_VALID;
 
-	sig_sge->lkey = pi_ctx->sig_mr->lkey;
-	sig_sge->addr = 0;
-	sig_sge->length = se_cmd->data_length;
+	rdma_wr->ib_sg[SIG].lkey = pi_ctx->sig_mr->lkey;
+	rdma_wr->ib_sg[SIG].addr = 0;
+	rdma_wr->ib_sg[SIG].length = se_cmd->data_length;
 	if (se_cmd->prot_op != TARGET_PROT_DIN_STRIP &&
 	    se_cmd->prot_op != TARGET_PROT_DOUT_INSERT)
 		/*
 		 * We have protection guards on the wire
 		 * so we need to set a larget transfer
 		 */
-		sig_sge->length += se_cmd->prot_length;
+		rdma_wr->ib_sg[SIG].length += se_cmd->prot_length;
 
 	pr_debug("sig_sge: addr: 0x%llx  length: %u lkey: %x\n",
-		 sig_sge->addr, sig_sge->length,
-		 sig_sge->lkey);
+		  rdma_wr->ib_sg[SIG].addr, rdma_wr->ib_sg[SIG].length,
+		  rdma_wr->ib_sg[SIG].lkey);
 err:
 	return ret;
 }
 
 static int
+isert_handle_prot_cmd(struct isert_conn *isert_conn,
+		      struct isert_cmd *isert_cmd,
+		      struct isert_rdma_wr *wr)
+{
+	struct isert_device *device = isert_conn->conn_device;
+	struct se_cmd *se_cmd = &isert_cmd->iscsi_cmd->se_cmd;
+	int ret;
+
+	if (!wr->fr_desc->pi_ctx) {
+		ret = isert_create_pi_ctx(wr->fr_desc,
+					  device->ib_device,
+					  isert_conn->conn_pd);
+		if (ret) {
+			pr_err("conn %p failed to allocate pi_ctx\n",
+				  isert_conn);
+			return ret;
+		}
+	}
+
+	if (se_cmd->t_prot_sg) {
+		ret = isert_map_data_buf(isert_conn, isert_cmd,
+					 se_cmd->t_prot_sg,
+					 se_cmd->t_prot_nents,
+					 se_cmd->prot_length,
+					 0, wr->iser_ib_op, &wr->prot);
+		if (ret) {
+			pr_err("conn %p failed to map protection buffer\n",
+				  isert_conn);
+			return ret;
+		}
+
+		memset(&wr->ib_sg[PROT], 0, sizeof(wr->ib_sg[PROT]));
+		ret = isert_fast_reg_mr(isert_conn, wr->fr_desc, &wr->prot,
+					ISERT_PROT_KEY_VALID, &wr->ib_sg[PROT]);
+		if (ret) {
+			pr_err("conn %p failed to fast reg mr\n",
+				  isert_conn);
+			goto unmap_prot_cmd;
+		}
+	}
+
+	ret = isert_reg_sig_mr(isert_conn, se_cmd, wr, wr->fr_desc);
+	if (ret) {
+		pr_err("conn %p failed to fast reg mr\n",
+			  isert_conn);
+		goto unmap_prot_cmd;
+	}
+	wr->fr_desc->ind |= ISERT_PROTECTED;
+
+	return 0;
+
+unmap_prot_cmd:
+	if (se_cmd->t_prot_sg)
+		isert_unmap_data_buf(isert_conn, &wr->prot);
+
+	return ret;
+}
+
+static int
 isert_reg_rdma(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
 	       struct isert_rdma_wr *wr)
 {
 	struct se_cmd *se_cmd = &cmd->se_cmd;
 	struct isert_cmd *isert_cmd = iscsit_priv_cmd(cmd);
 	struct isert_conn *isert_conn = conn->context;
-	struct ib_sge data_sge;
-	struct ib_send_wr *send_wr;
 	struct fast_reg_descriptor *fr_desc = NULL;
+	struct ib_send_wr *send_wr;
+	struct ib_sge *ib_sg;
 	u32 offset;
 	int ret = 0;
 	unsigned long flags;
@@ -2876,38 +2930,21 @@ isert_reg_rdma(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
 	}
 
 	ret = isert_fast_reg_mr(isert_conn, fr_desc, &wr->data,
-				ISERT_DATA_KEY_VALID, &data_sge);
+				ISERT_DATA_KEY_VALID, &wr->ib_sg[DATA]);
 	if (ret)
 		goto unmap_cmd;
 
 	if (se_cmd->prot_op != TARGET_PROT_NORMAL) {
-		struct ib_sge prot_sge, sig_sge;
-
-		if (se_cmd->t_prot_sg) {
-			ret = isert_map_data_buf(isert_conn, isert_cmd,
-						 se_cmd->t_prot_sg,
-						 se_cmd->t_prot_nents,
-						 se_cmd->prot_length,
-						 0, wr->iser_ib_op, &wr->prot);
-			if (ret)
-				goto unmap_cmd;
-
-			ret = isert_fast_reg_mr(isert_conn, fr_desc, &wr->prot,
-						ISERT_PROT_KEY_VALID, &prot_sge);
-			if (ret)
-				goto unmap_prot_cmd;
-		}
-
-		ret = isert_reg_sig_mr(isert_conn, se_cmd, fr_desc,
-				       &data_sge, &prot_sge, &sig_sge);
+		ret = isert_handle_prot_cmd(isert_conn, isert_cmd, wr);
 		if (ret)
-			goto unmap_prot_cmd;
+			goto unmap_cmd;
 
-		fr_desc->ind |= ISERT_PROTECTED;
-		memcpy(&wr->s_ib_sge, &sig_sge, sizeof(sig_sge));
-	} else
-		memcpy(&wr->s_ib_sge, &data_sge, sizeof(data_sge));
+		ib_sg = &wr->ib_sg[SIG];
+	} else {
+		ib_sg = &wr->ib_sg[DATA];
+	}
 
+	memcpy(&wr->s_ib_sge, ib_sg, sizeof(*ib_sg));
 	wr->ib_sge = &wr->s_ib_sge;
 	wr->send_wr_num = 1;
 	memset(&wr->s_send_wr, 0, sizeof(*send_wr));
@@ -2932,9 +2969,7 @@ isert_reg_rdma(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
 	}
 
 	return 0;
-unmap_prot_cmd:
-	if (se_cmd->t_prot_sg)
-		isert_unmap_data_buf(isert_conn, &wr->prot);
+
 unmap_cmd:
 	if (fr_desc) {
 		spin_lock_irqsave(&isert_conn->conn_lock, flags);
diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h
index 9372d4d..2e7868c 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.h
+++ b/drivers/infiniband/ulp/isert/ib_isert.h
@@ -82,6 +82,12 @@ struct isert_data_buf {
 	enum dma_data_direction dma_dir;
 };
 
+enum {
+	DATA = 0,
+	PROT = 1,
+	SIG = 2,
+};
+
 struct isert_rdma_wr {
 	struct list_head	wr_list;
 	struct isert_cmd	*isert_cmd;
@@ -91,6 +97,7 @@ struct isert_rdma_wr {
 	int			send_wr_num;
 	struct ib_send_wr	*send_wr;
 	struct ib_send_wr	s_send_wr;
+	struct ib_sge		ib_sg[3];
 	struct isert_data_buf	data;
 	struct isert_data_buf	prot;
 	struct fast_reg_descriptor *fr_desc;