test: firmware_class: report errors properly on failure

request_firmware() failures currently won't get reported at all (the
error code is discarded). What's more, we get confusing messages, like:

    # echo -n notafile > /sys/devices/virtual/misc/test_firmware/trigger_request
    [ 8280.311856] test_firmware: loading 'notafile'
    [ 8280.317042] test_firmware: load of 'notafile' failed: -2
    [ 8280.322445] test_firmware: loaded: 0
    # echo $?
    0

Report the failures via write() errors, and don't say we "loaded"
anything.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/lib/test_firmware.c b/lib/test_firmware.c
index 86374c1c49a4..841191061816 100644
--- a/lib/test_firmware.c
+++ b/lib/test_firmware.c
@@ -65,14 +65,19 @@ static ssize_t trigger_request_store(struct device *dev,
         release_firmware(test_firmware);
         test_firmware = NULL;
         rc = request_firmware(&test_firmware, name, dev);
-        if (rc)
+        if (rc) {
                 pr_info("load of '%s' failed: %d\n", name, rc);
-        pr_info("loaded: %zu\n", test_firmware ? test_firmware->size : 0);
+                goto out;
+        }
+        pr_info("loaded: %zu\n", test_firmware->size);
+        rc = count;
+
+out:
         mutex_unlock(&test_fw_mutex);
 
         kfree(name);
 
-        return count;
+        return rc;
 }
 static DEVICE_ATTR_WO(trigger_request);