ipmi:msghandler: Handle error returns from the SMI sender

It used to be, until recently, that the sender operation on the low
level interfaces would not fail.  That's not the case any more with
recent changes.

So check the return value from the sender operation, and propagate it
back up from there and handle the errors in all places.

Reported-by: Rafael J. Wysocki <rafael@kernel.org>
Fixes: bc3a9d2 ("ipmi:si: Gracefully handle if the BMC is non-functional")
Cc: stable@vger.kernel.org # 4.18
Signed-off-by: Corey Minyard <corey@minyard.net>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>

Author: cminyard

drivers/char/ipmi/ipmi_msghandler.c

@@ -1887,19 +1887,32 @@ static struct ipmi_smi_msg *smi_add_send_msg(struct ipmi_smi *intf,
 	return smi_msg;
 }
 
-static void smi_send(struct ipmi_smi *intf,
+static int smi_send(struct ipmi_smi *intf,
 		     const struct ipmi_smi_handlers *handlers,
 		     struct ipmi_smi_msg *smi_msg, int priority)
 {
 	int run_to_completion = READ_ONCE(intf->run_to_completion);
 	unsigned long flags = 0;
+	int rv = 0;
 
 	ipmi_lock_xmit_msgs(intf, run_to_completion, &flags);
 	smi_msg = smi_add_send_msg(intf, smi_msg, priority);
 	ipmi_unlock_xmit_msgs(intf, run_to_completion, &flags);
 
-	if (smi_msg)
-		handlers->sender(intf->send_info, smi_msg);
+	if (smi_msg) {
+		rv = handlers->sender(intf->send_info, smi_msg);
+		if (rv) {
+			ipmi_lock_xmit_msgs(intf, run_to_completion, &flags);
+			intf->curr_msg = NULL;
+			ipmi_unlock_xmit_msgs(intf, run_to_completion, &flags);
+			/*
+			 * Something may have been added to the transmit
+			 * queue, so schedule a check for that.
+			 */
+			queue_work(system_wq, &intf->smi_work);
+		}
+	}
+	return rv;
 }
 
 static bool is_maintenance_mode_cmd(struct kernel_ipmi_msg *msg)
@@ -2312,6 +2325,7 @@ static int i_ipmi_request(struct ipmi_user     *user,
 	struct ipmi_recv_msg *recv_msg;
 	int run_to_completion = READ_ONCE(intf->run_to_completion);
 	int rv = 0;
+	bool in_seq_table = false;
 
 	if (supplied_recv) {
 		recv_msg = supplied_recv;
@@ -2365,33 +2379,50 @@ static int i_ipmi_request(struct ipmi_user     *user,
 		rv = i_ipmi_req_ipmb(intf, addr, msgid, msg, smi_msg, recv_msg,
 				     source_address, source_lun,
 				     retries, retry_time_ms);
+		in_seq_table = true;
 	} else if (is_ipmb_direct_addr(addr)) {
 		rv = i_ipmi_req_ipmb_direct(intf, addr, msgid, msg, smi_msg,
 					    recv_msg, source_lun);
 	} else if (is_lan_addr(addr)) {
 		rv = i_ipmi_req_lan(intf, addr, msgid, msg, smi_msg, recv_msg,
 				    source_lun, retries, retry_time_ms);
+		in_seq_table = true;
 	} else {
-	    /* Unknown address type. */
+		/* Unknown address type. */
 		ipmi_inc_stat(intf, sent_invalid_commands);
 		rv = -EINVAL;
 	}
 
-	if (rv) {
-out_err:
-		if (!supplied_smi)
-			ipmi_free_smi_msg(smi_msg);
-		if (!supplied_recv)
-			ipmi_free_recv_msg(recv_msg);
-	} else {
+	if (!rv) {
 		dev_dbg(intf->si_dev, "Send: %*ph\n",
 			smi_msg->data_size, smi_msg->data);
 
-		smi_send(intf, intf->handlers, smi_msg, priority);
+		rv = smi_send(intf, intf->handlers, smi_msg, priority);
+		if (rv != IPMI_CC_NO_ERROR)
+			/* smi_send() returns an IPMI err, return a Linux one. */
+			rv = -EIO;
+		if (rv && in_seq_table) {
+			/*
+			 * If it's in the sequence table, it will be
+			 * retried later, so ignore errors.
+			 */
+			rv = 0;
+			/* But we need to fix the timeout. */
+			intf_start_seq_timer(intf, smi_msg->msgid);
+			ipmi_free_smi_msg(smi_msg);
+			smi_msg = NULL;
+		}
 	}
+out_err:
 	if (!run_to_completion)
 		mutex_unlock(&intf->users_mutex);
 
+	if (rv) {
+		if (!supplied_smi)
+			ipmi_free_smi_msg(smi_msg);
+		if (!supplied_recv)
+			ipmi_free_recv_msg(recv_msg);
+	}
 	return rv;
 }
 
@@ -3965,12 +3996,12 @@ static int handle_ipmb_get_msg_cmd(struct ipmi_smi *intf,
 		dev_dbg(intf->si_dev, "Invalid command: %*ph\n",
 			msg->data_size, msg->data);
 
-		smi_send(intf, intf->handlers, msg, 0);
-		/*
-		 * We used the message, so return the value that
-		 * causes it to not be freed or queued.
-		 */
-		rv = -1;
+		if (smi_send(intf, intf->handlers, msg, 0) == IPMI_CC_NO_ERROR)
+			/*
+			 * We used the message, so return the value that
+			 * causes it to not be freed or queued.
+			 */
+			rv = -1;
 	} else if (!IS_ERR(recv_msg)) {
 		/* Extract the source address from the data. */
 		ipmb_addr = (struct ipmi_ipmb_addr *) &recv_msg->addr;
@@ -4044,12 +4075,12 @@ static int handle_ipmb_direct_rcv_cmd(struct ipmi_smi *intf,
 		msg->data[4] = IPMI_INVALID_CMD_COMPLETION_CODE;
 		msg->data_size = 5;
 
-		smi_send(intf, intf->handlers, msg, 0);
-		/*
-		 * We used the message, so return the value that
-		 * causes it to not be freed or queued.
-		 */
-		rv = -1;
+		if (smi_send(intf, intf->handlers, msg, 0) == IPMI_CC_NO_ERROR)
+			/*
+			 * We used the message, so return the value that
+			 * causes it to not be freed or queued.
+			 */
+			rv = -1;
 	} else if (!IS_ERR(recv_msg)) {
 		/* Extract the source address from the data. */
 		daddr = (struct ipmi_ipmb_direct_addr *)&recv_msg->addr;
@@ -4189,7 +4220,7 @@ static int handle_lan_get_msg_cmd(struct ipmi_smi *intf,
 				  struct ipmi_smi_msg *msg)
 {
 	struct cmd_rcvr          *rcvr;
-	int                      rv = 0;
+	int                      rv = 0; /* Free by default */
 	unsigned char            netfn;
 	unsigned char            cmd;
 	unsigned char            chan;
@@ -4242,12 +4273,12 @@ static int handle_lan_get_msg_cmd(struct ipmi_smi *intf,
 		dev_dbg(intf->si_dev, "Invalid command: %*ph\n",
 			msg->data_size, msg->data);
 
-		smi_send(intf, intf->handlers, msg, 0);
-		/*
-		 * We used the message, so return the value that
-		 * causes it to not be freed or queued.
-		 */
-		rv = -1;
+		if (smi_send(intf, intf->handlers, msg, 0) == IPMI_CC_NO_ERROR)
+			/*
+			 * We used the message, so return the value that
+			 * causes it to not be freed or queued.
+			 */
+			rv = -1;
 	} else if (!IS_ERR(recv_msg)) {
 		/* Extract the source address from the data. */
 		lan_addr = (struct ipmi_lan_addr *) &recv_msg->addr;
@@ -5056,7 +5087,12 @@ static void check_msg_timeout(struct ipmi_smi *intf, struct seq_table *ent,
 				ipmi_inc_stat(intf,
 					      retransmitted_ipmb_commands);
 
-			smi_send(intf, intf->handlers, smi_msg, 0);
+			/* If this fails we'll retry later or timeout. */
+			if (smi_send(intf, intf->handlers, smi_msg, 0) != IPMI_CC_NO_ERROR) {
+				/* But fix the timeout. */
+				intf_start_seq_timer(intf, smi_msg->msgid);
+				ipmi_free_smi_msg(smi_msg);
+			}
 		} else
 			ipmi_free_smi_msg(smi_msg);