firmware: ensure the firmware cache is not used on incompatible calls

request_firmware_into_buf() explicitly disables the firmware cache, meanwhile the firmware cache cannot be used when request_firmware_nowait() is used without the uevent. Enforce a sanity check for this to avoid future issues undocumented behaviours should misuses of the firmware cache happen later. One of the reasons we want to enforce this is the firmware cache is used for helping with suspend/resume, and if incompatible calls use it they can stall suspend. Signed-off-by: Luis R. Rodriguez <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
laijs · Mar 20, 2018 · 995e869 · 995e869
1 parent 9952db7
commit 995e869
Showing 1 changed file with 14 additions and 0 deletions.
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
@@ -431,6 +431,11 @@ static int fw_add_devm_name(struct device *dev, const char *name)
 	return 0;
 }
 #else
+static bool fw_cache_is_setup(struct device *dev, const char *name)
+{
+	return false;
+}
+
 static int fw_add_devm_name(struct device *dev, const char *name)
 {
 	return 0;
@@ -672,6 +677,9 @@ request_firmware_into_buf(const struct firmware **firmware_p, const char *name,
 {
 	int ret;
 
+	if (fw_cache_is_setup(device, name))
+		return -EOPNOTSUPP;
+
 	__module_get(THIS_MODULE);
 	ret = _request_firmware(firmware_p, name, device, buf, size,
 				FW_OPT_UEVENT | FW_OPT_NOCACHE);
@@ -769,6 +777,12 @@ request_firmware_nowait(
 	fw_work->opt_flags = FW_OPT_NOWAIT |
 		(uevent ? FW_OPT_UEVENT : FW_OPT_USERHELPER);
 
+	if (!uevent && fw_cache_is_setup(device, name)) {
+		kfree_const(fw_work->name);
+		kfree(fw_work);
+		return -EOPNOTSUPP;
+	}
+
 	if (!try_module_get(module)) {
 		kfree_const(fw_work->name);
 		kfree(fw_work);