ACPI: EC: Abort address space access upon error

When a multi-byte address space access is requested, acpi_ec_read()/
acpi_ec_write() is being called multiple times.

Abort such operations if a single call to acpi_ec_read() /
acpi_ec_write() fails, as the data read from / written to the EC
might be incomplete.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/ec.c

@@ -1333,10 +1333,13 @@ acpi_ec_space_handler(u32 function, acpi_physical_address address,
 	if (ec->busy_polling || bits > 8)
 		acpi_ec_burst_enable(ec);
 
-	for (i = 0; i < bytes; ++i, ++address, ++value)
+	for (i = 0; i < bytes; ++i, ++address, ++value) {
 		result = (function == ACPI_READ) ?
 			acpi_ec_read(ec, address, value) :
 			acpi_ec_write(ec, address, *value);
+		if (result < 0)
+			break;
+	}
 
 	if (ec->busy_polling || bits > 8)
 		acpi_ec_burst_disable(ec);