iscsi/isert-target: Refactor ISCSI_OP_NOOP RX handling

This patch refactors ISCSI_OP_NOOP handling within iscsi-target in
order to handle iscsi_nopout payloads in a transport specific manner.

This includes splitting existing iscsit_handle_nop_out() into
iscsit_setup_nop_out() and iscsit_process_nop_out() calls, and
makes iscsit_handle_nop_out() be only used internally by traditional
iscsi socket calls.

Next update iser-target code to use new callers and add FIXME for
the handling iscsi_nopout payloads.  Also fix reject response handling
in iscsit_setup_nop_out() to use proper iscsit_add_reject_from_cmd().

v2: Fix uninitialized iscsit_handle_nop_out() payload_length usage (Fengguang)
v3: Remove left-over dead code in iscsit_setup_nop_out() (DanC)

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

3 files changed, 115 insertions, 88 deletions

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 41712f096515..c48c9481025c 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -1001,6 +1001,25 @@ isert_handle_iscsi_dataout(struct isert_conn *isert_conn,
 }
 
 static int
+isert_handle_nop_out(struct isert_conn *isert_conn, struct isert_cmd *isert_cmd,
+                     struct iser_rx_desc *rx_desc, unsigned char *buf)
+{
+        struct iscsi_cmd *cmd = &isert_cmd->iscsi_cmd;
+        struct iscsi_conn *conn = isert_conn->conn;
+        struct iscsi_nopout *hdr = (struct iscsi_nopout *)buf;
+        int rc;
+
+        rc = iscsit_setup_nop_out(conn, cmd, hdr);
+        if (rc < 0)
+                return rc;
+        /*
+         * FIXME: Add support for NOPOUT payload using unsolicited RDMA payload
+         */
+
+        return iscsit_process_nop_out(conn, cmd, hdr);
+}
+
+static int
 isert_rx_opcode(struct isert_conn *isert_conn, struct iser_rx_desc *rx_desc,
                 uint32_t read_stag, uint64_t read_va,
                 uint32_t write_stag, uint64_t write_va)
@@ -1032,7 +1051,9 @@ isert_rx_opcode(struct isert_conn *isert_conn, struct iser_rx_desc *rx_desc,
                 if (!cmd)
                         break;
 
-                ret = iscsit_handle_nop_out(conn, cmd, (unsigned char *)hdr);
+                isert_cmd = container_of(cmd, struct isert_cmd, iscsi_cmd);
+                ret = isert_handle_nop_out(isert_conn, isert_cmd,
+                                           rx_desc, (unsigned char *)hdr);
                 break;
         case ISCSI_OP_SCSI_DATA_OUT:
                 ret = isert_handle_iscsi_dataout(isert_conn, rx_desc,
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index cc43d4163adc..f684627244bf 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -1535,24 +1535,16 @@ static int iscsit_handle_data_out(struct iscsi_conn *conn, unsigned char *buf)
         return iscsit_check_dataout_payload(cmd, hdr, data_crc_failed);
 }
 
-int iscsit_handle_nop_out(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
-                        unsigned char *buf)
+int iscsit_setup_nop_out(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
+                         struct iscsi_nopout *hdr)
 {
-        unsigned char *ping_data = NULL;
-        int cmdsn_ret, niov = 0, ret = 0, rx_got, rx_size;
-        u32 checksum, data_crc, padding = 0, payload_length;
-        struct iscsi_cmd *cmd_p = NULL;
-        struct kvec *iov = NULL;
-        struct iscsi_nopout *hdr;
-
-        hdr                     = (struct iscsi_nopout *) buf;
-        payload_length          = ntoh24(hdr->dlength);
+        u32 payload_length = ntoh24(hdr->dlength);
 
         if (hdr->itt == RESERVED_ITT && !(hdr->opcode & ISCSI_OP_IMMEDIATE)) {
                 pr_err("NOPOUT ITT is reserved, but Immediate Bit is"
                         " not set, protocol error.\n");
-                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
-                                        buf, conn);
+                return iscsit_add_reject_from_cmd(ISCSI_REASON_PROTOCOL_ERROR,
+                                        1, 0, (unsigned char *)hdr, cmd);
         }
 
         if (payload_length > conn->conn_ops->MaxXmitDataSegmentLength) {
@@ -1560,8 +1552,8 @@ int iscsit_handle_nop_out(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                         " greater than MaxXmitDataSegmentLength: %u, protocol"
                         " error.\n", payload_length,
                         conn->conn_ops->MaxXmitDataSegmentLength);
-                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
-                                        buf, conn);
+                return iscsit_add_reject_from_cmd(ISCSI_REASON_PROTOCOL_ERROR,
+                                        1, 0, (unsigned char *)hdr, cmd);
         }
 
         pr_debug("Got NOPOUT Ping %s ITT: 0x%08x, TTT: 0x%08x,"
@@ -1577,11 +1569,6 @@ int iscsit_handle_nop_out(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
          * can contain ping data.
          */
         if (hdr->ttt == cpu_to_be32(0xFFFFFFFF)) {
-                if (!cmd)
-                        return iscsit_add_reject(
-                                        ISCSI_REASON_BOOKMARK_NO_RESOURCES,
-                                        1, buf, conn);
-
                 cmd->iscsi_opcode       = ISCSI_OP_NOOP_OUT;
                 cmd->i_state            = ISTATE_SEND_NOPIN;
                 cmd->immediate_cmd      = ((hdr->opcode & ISCSI_OP_IMMEDIATE) ?
@@ -1593,8 +1580,87 @@ int iscsit_handle_nop_out(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                 cmd->data_direction     = DMA_NONE;
         }
 
+        return 0;
+}
+EXPORT_SYMBOL(iscsit_setup_nop_out);
+
+int iscsit_process_nop_out(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
+                           struct iscsi_nopout *hdr)
+{
+        struct iscsi_cmd *cmd_p = NULL;
+        int cmdsn_ret = 0;
+        /*
+         * Initiator is expecting a NopIN ping reply..
+         */
+        if (hdr->itt != RESERVED_ITT) {
+                BUG_ON(!cmd);
+
+                spin_lock_bh(&conn->cmd_lock);
+                list_add_tail(&cmd->i_conn_node, &conn->conn_cmd_list);
+                spin_unlock_bh(&conn->cmd_lock);
+
+                iscsit_ack_from_expstatsn(conn, be32_to_cpu(hdr->exp_statsn));
+
+                if (hdr->opcode & ISCSI_OP_IMMEDIATE) {
+                        iscsit_add_cmd_to_response_queue(cmd, conn,
+                                                         cmd->i_state);
+                        return 0;
+                }
+
+                cmdsn_ret = iscsit_sequence_cmd(conn, cmd, hdr->cmdsn);
+                if (cmdsn_ret == CMDSN_LOWER_THAN_EXP)
+                        return 0;
+
+                if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER)
+                        return iscsit_add_reject_from_cmd(
+                                        ISCSI_REASON_PROTOCOL_ERROR,
+                                        1, 0, (unsigned char *)hdr, cmd);
+
+                return 0;
+        }
+        /*
+         * This was a response to a unsolicited NOPIN ping.
+         */
+        if (hdr->ttt != cpu_to_be32(0xFFFFFFFF)) {
+                cmd_p = iscsit_find_cmd_from_ttt(conn, be32_to_cpu(hdr->ttt));
+                if (!cmd_p)
+                        return -EINVAL;
+
+                iscsit_stop_nopin_response_timer(conn);
+
+                cmd_p->i_state = ISTATE_REMOVE;
+                iscsit_add_cmd_to_immediate_queue(cmd_p, conn, cmd_p->i_state);
+
+                iscsit_start_nopin_timer(conn);
+                return 0;
+        }
+        /*
+         * Otherwise, initiator is not expecting a NOPIN is response.
+         * Just ignore for now.
+         */
+        return 0;
+}
+EXPORT_SYMBOL(iscsit_process_nop_out);
+
+static int iscsit_handle_nop_out(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
+                                 unsigned char *buf)
+{
+        unsigned char *ping_data = NULL;
+        struct iscsi_nopout *hdr = (struct iscsi_nopout *)buf;
+        struct kvec *iov = NULL;
+        u32 payload_length = ntoh24(hdr->dlength);
+        int ret;
+
+        ret = iscsit_setup_nop_out(conn, cmd, hdr);
+        if (ret < 0)
+                return ret;
+        /*
+         * Handle NOP-OUT payload for traditional iSCSI sockets
+         */
         if (payload_length && hdr->ttt == cpu_to_be32(0xFFFFFFFF)) {
-                rx_size = payload_length;
+                u32 checksum, data_crc, padding = 0;
+                int niov = 0, rx_got, rx_size = payload_length;
+
                 ping_data = kzalloc(payload_length + 1, GFP_KERNEL);
                 if (!ping_data) {
                         pr_err("Unable to allocate memory for"
@@ -1673,76 +1739,14 @@ int iscsit_handle_nop_out(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                 pr_debug("Ping Data: \"%s\"\n", ping_data);
         }
 
-        if (hdr->itt != RESERVED_ITT) {
-                if (!cmd) {
-                        pr_err("Checking CmdSN for NOPOUT,"
-                                " but cmd is NULL!\n");
-                        return -1;
-                }
-                /*
-                 * Initiator is expecting a NopIN ping reply,
-                 */
-                spin_lock_bh(&conn->cmd_lock);
-                list_add_tail(&cmd->i_conn_node, &conn->conn_cmd_list);
-                spin_unlock_bh(&conn->cmd_lock);
-
-                iscsit_ack_from_expstatsn(conn, be32_to_cpu(hdr->exp_statsn));
-
-                if (hdr->opcode & ISCSI_OP_IMMEDIATE) {
-                        iscsit_add_cmd_to_response_queue(cmd, conn,
-                                        cmd->i_state);
-                        return 0;
-                }
-
-                cmdsn_ret = iscsit_sequence_cmd(conn, cmd, hdr->cmdsn);
-                if (cmdsn_ret == CMDSN_LOWER_THAN_EXP) {
-                        ret = 0;
-                        goto ping_out;
-                }
-                if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER)
-                        return iscsit_add_reject_from_cmd(
-                                        ISCSI_REASON_PROTOCOL_ERROR,
-                                        1, 0, buf, cmd);
-
-                return 0;
-        }
-
-        if (hdr->ttt != cpu_to_be32(0xFFFFFFFF)) {
-                /*
-                 * This was a response to a unsolicited NOPIN ping.
-                 */
-                cmd_p = iscsit_find_cmd_from_ttt(conn, be32_to_cpu(hdr->ttt));
-                if (!cmd_p)
-                        return -1;
-
-                iscsit_stop_nopin_response_timer(conn);
-
-                cmd_p->i_state = ISTATE_REMOVE;
-                iscsit_add_cmd_to_immediate_queue(cmd_p, conn, cmd_p->i_state);
-                iscsit_start_nopin_timer(conn);
-        } else {
-                /*
-                 * Initiator is not expecting a NOPIN is response.
-                 * Just ignore for now.
-                 *
-                 * iSCSI v19-91 10.18
-                 * "A NOP-OUT may also be used to confirm a changed
-                 *  ExpStatSN if another PDU will not be available
-                 *  for a long time."
-                 */
-                ret = 0;
-                goto out;
-        }
-
-        return 0;
+        return iscsit_process_nop_out(conn, cmd, hdr);
 out:
         if (cmd)
                 iscsit_free_cmd(cmd, false);
-ping_out:
+
         kfree(ping_data);
         return ret;
 }
-EXPORT_SYMBOL(iscsit_handle_nop_out);
 
 int
 iscsit_handle_task_mgt_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
diff --git a/include/target/iscsi/iscsi_transport.h b/include/target/iscsi/iscsi_transport.h
index 23a87d0cd72c..ecb53ea6d1c7 100644
--- a/include/target/iscsi/iscsi_transport.h
+++ b/include/target/iscsi/iscsi_transport.h
@@ -45,8 +45,10 @@ extern int iscsit_check_dataout_hdr(struct iscsi_conn *, unsigned char *,
                                 struct iscsi_cmd **);
 extern int iscsit_check_dataout_payload(struct iscsi_cmd *, struct iscsi_data *,
                                 bool);
-extern int iscsit_handle_nop_out(struct iscsi_conn *, struct iscsi_cmd *,
-                                unsigned char *);
+extern int iscsit_setup_nop_out(struct iscsi_conn *, struct iscsi_cmd *,
+                                struct iscsi_nopout *);
+extern int iscsit_process_nop_out(struct iscsi_conn *, struct iscsi_cmd *,
+                                struct iscsi_nopout *);
 extern int iscsit_handle_logout_cmd(struct iscsi_conn *, struct iscsi_cmd *,
                                 unsigned char *);
 extern int iscsit_handle_task_mgt_cmd(struct iscsi_conn *, struct iscsi_cmd *,