usb: typec: ucsi: Fix command cancellation

The Cancel command was passed to the write callback as the
offset instead of as the actual command which caused NULL
pointer dereference.

Reported-by: Stephan Bolten <stephan.bolten@gmx.net>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217517
Fixes: 094902b ("usb: typec: ucsi: Always cancel the command if PPM reports BUSY condition")
Cc: stable@vger.kernel.org
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Message-ID: <20230606115802.79339-1-heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Heikki Krogerus

drivers/usb/typec/ucsi/ucsi.c

@@ -132,10 +132,8 @@ static int ucsi_exec_command(struct ucsi *ucsi, u64 cmd)
 	if (ret)
 		return ret;
 
-	if (cci & UCSI_CCI_BUSY) {
-		ucsi->ops->async_write(ucsi, UCSI_CANCEL, NULL, 0);
-		return -EBUSY;
-	}
+	if (cmd != UCSI_CANCEL && cci & UCSI_CCI_BUSY)
+		return ucsi_exec_command(ucsi, UCSI_CANCEL);
 
 	if (!(cci & UCSI_CCI_COMMAND_COMPLETE))
 		return -EIO;
@@ -149,6 +147,11 @@ static int ucsi_exec_command(struct ucsi *ucsi, u64 cmd)
 		return ucsi_read_error(ucsi);
 	}
 
+	if (cmd == UCSI_CANCEL && cci & UCSI_CCI_CANCEL_COMPLETE) {
+		ret = ucsi_acknowledge_command(ucsi);
+		return ret ? ret : -EBUSY;
+	}
+
 	return UCSI_CCI_LENGTH(cci);
 }