pstore/ram: Probe as early as possible

Registering the platform driver before module_init allows us to log oopses
that happen during device probing.

This requires changing module_init to postcore_initcall, and switching
from platform_driver_probe to platform_driver_register because the
platform device is not registered when the platform driver is registered;
and because we use driver_register, now can't use create_bundle() (since
it will try to register the same driver once again), so we have to switch
to platform_device_register_data().

Also, some __init -> __devinit changes were needed.

Overall, the registration logic is now much clearer, since we have only
one driver registration point, and just an optional dummy device, which
is created from the module parameters.
Suggested-by: Colin Cross <ccross@android.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/pstore/ram.c

@@ -330,7 +330,7 @@ static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
 	return 0;
 }
 
-static int __init ramoops_probe(struct platform_device *pdev)
+static int __devinit ramoops_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct ramoops_platform_data *pdata = pdev->dev.platform_data;
@@ -452,6 +452,7 @@ static int __exit ramoops_remove(struct platform_device *pdev)
 }
 
 static struct platform_driver ramoops_driver = {
+	.probe		= ramoops_probe,
 	.remove		= __exit_p(ramoops_remove),
 	.driver		= {
 		.name	= "ramoops",
@@ -459,46 +460,46 @@ static struct platform_driver ramoops_driver = {
 	},
 };
 
-static int __init ramoops_init(void)
+static void ramoops_register_dummy(void)
 {
-	int ret;
-	ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
-	if (ret == -ENODEV) {
-		/*
-		 * If we didn't find a platform device, we use module parameters
-		 * building platform data on the fly.
-		 */
-		pr_info("platform device not found, using module parameters\n");
-		dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
-				     GFP_KERNEL);
-		if (!dummy_data)
-			return -ENOMEM;
-		dummy_data->mem_size = mem_size;
-		dummy_data->mem_address = mem_address;
-		dummy_data->record_size = record_size;
-		dummy_data->console_size = ramoops_console_size;
-		dummy_data->dump_oops = dump_oops;
-		dummy_data->ecc = ramoops_ecc;
-		dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
-			NULL, 0, dummy_data,
-			sizeof(struct ramoops_platform_data));
-
-		if (IS_ERR(dummy))
-			ret = PTR_ERR(dummy);
-		else
-			ret = 0;
+	if (!mem_size)
+		return;
+
+	pr_info("using module parameters\n");
+
+	dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
+	if (!dummy_data) {
+		pr_info("could not allocate pdata\n");
+		return;
 	}
 
-	return ret;
+	dummy_data->mem_size = mem_size;
+	dummy_data->mem_address = mem_address;
+	dummy_data->record_size = record_size;
+	dummy_data->console_size = ramoops_console_size;
+	dummy_data->dump_oops = dump_oops;
+	dummy_data->ecc = ramoops_ecc;
+
+	dummy = platform_device_register_data(NULL, "ramoops", -1,
+			dummy_data, sizeof(struct ramoops_platform_data));
+	if (IS_ERR(dummy)) {
+		pr_info("could not create platform device: %ld\n",
+			PTR_ERR(dummy));
+	}
+}
+
+static int __init ramoops_init(void)
+{
+	ramoops_register_dummy();
+	return platform_driver_register(&ramoops_driver);
 }
+postcore_initcall(ramoops_init);
 
 static void __exit ramoops_exit(void)
 {
 	platform_driver_unregister(&ramoops_driver);
 	kfree(dummy_data);
 }
-
-module_init(ramoops_init);
 module_exit(ramoops_exit);
 
 MODULE_LICENSE("GPL");

fs/pstore/ram_core.c

@@ -390,7 +390,8 @@ static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
 	return 0;
 }
 
-static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool ecc)
+static int __devinit persistent_ram_post_init(struct persistent_ram_zone *prz,
+					      bool ecc)
 {
 	int ret;
 
@@ -436,9 +437,9 @@ void persistent_ram_free(struct persistent_ram_zone *prz)
 	kfree(prz);
 }
 
-struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
-						       size_t size,
-						       bool ecc)
+struct persistent_ram_zone * __devinit persistent_ram_new(phys_addr_t start,
+							  size_t size,
+							  bool ecc)
 {
 	struct persistent_ram_zone *prz;
 	int ret = -ENOMEM;

include/linux/pstore_ram.h

@@ -48,9 +48,9 @@ struct persistent_ram_zone {
 	size_t old_log_size;
 };
 
-struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
-						       size_t size,
-						       bool ecc);
+struct persistent_ram_zone * __devinit persistent_ram_new(phys_addr_t start,
+							  size_t size,
+							  bool ecc);
 void persistent_ram_free(struct persistent_ram_zone *prz);
 void persistent_ram_zap(struct persistent_ram_zone *prz);