[PATCH 1/3 v2] firmware: Convert firmware path setup from an array to a list

[Dimitris Papastamos <dp@opensource.wolfsonmicro.com>]

In preparation to support dynamic listing/updating of firmware
paths via procfs, this patch converts the firmware path configuration
from an array to a list.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
---
 drivers/base/firmware_class.c | 74 +++++++++++++++++++++++++++++++++++++------
 1 file changed, 65 insertions(+), 9 deletions(-)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 8945f4e..d76152b 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -36,6 +36,13 @@ MODULE_AUTHOR("Manuel Estrada Sainz");
 MODULE_DESCRIPTION("Multi purpose firmware loading support");
 MODULE_LICENSE("GPL");
 
+struct fw_path_rec {
+	const char *name;
+	struct list_head list;
+};
+
+static LIST_HEAD(fw_path_list);
+
 /* Builtin firmware support */
 
 #ifdef CONFIG_FW_LOADER
@@ -267,12 +274,6 @@ static void fw_free_buf(struct firmware_buf *buf)
 }
 
 /* direct firmware loading support */
-static const char *fw_path[] = {
-	"/lib/firmware/updates/" UTS_RELEASE,
-	"/lib/firmware/updates",
-	"/lib/firmware/" UTS_RELEASE,
-	"/lib/firmware"
-};
 
 /* Don't inline this: 'struct kstat' is biggish */
 static noinline long fw_file_size(struct file *file)
@@ -309,13 +310,13 @@ static bool fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf
 
 static bool fw_get_filesystem_firmware(struct firmware_buf *buf)
 {
-	int i;
 	bool success = false;
 	char *path = __getname();
+	struct fw_path_rec *fwp;
 
-	for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
+	list_for_each_entry(fwp, &fw_path_list, list) {
 		struct file *file;
-		snprintf(path, PATH_MAX, "%s/%s", fw_path[i], buf->fw_id);
+		snprintf(path, PATH_MAX, "%s/%s", fwp->name, buf->fw_id);
 
 		file = filp_open(path, O_RDONLY, 0);
 		if (IS_ERR(file))
@@ -1423,6 +1424,50 @@ static int fw_cache_piggyback_on_request(const char *name)
 }
 #endif
 
+static void fw_free_path_list(void)
+{
+	struct fw_path_rec *fwp;
+
+	while (!list_empty(&fw_path_list)) {
+		fwp = list_first_entry(&fw_path_list,
+				       struct fw_path_rec,
+				       list);
+		kfree(fwp->name);
+		list_del(&fwp->list);
+		kfree(fwp);
+	}
+}
+
+static int fw_populate_path_list(void)
+{
+	int i;
+	struct fw_path_rec *fwp;
+	static const char *fw_path[] = {
+		"/lib/firmware/updates/" UTS_RELEASE,
+		"/lib/firmware/updates",
+		"/lib/firmware/" UTS_RELEASE,
+		"/lib/firmware"
+	};
+
+	for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
+		fwp = kmalloc(sizeof(*fwp), GFP_KERNEL);
+		if (!fwp)
+			goto err_fwp_alloc;
+		fwp->name = kstrdup(fw_path[i], GFP_KERNEL);
+		if (!fwp->name)
+			goto err_fwp_name_alloc;
+		list_add_tail(&fwp->list, &fw_path_list);
+	}
+
+	return 0;
+
+err_fwp_name_alloc:
+	kfree(fwp);
+err_fwp_alloc:
+	fw_free_path_list();
+	return -ENOMEM;
+}
+
 static void __init fw_cache_init(void)
 {
 	spin_lock_init(&fw_cache.lock);
@@ -1445,7 +1490,17 @@ static void __init fw_cache_init(void)
 
 static int __init firmware_class_init(void)
 {
+	int ret;
+
 	fw_cache_init();
+
+	ret = fw_populate_path_list();
+	if (ret < 0) {
+		pr_err("%s: Failed to populate firmware path list: %d\n",
+		       __func__, ret);
+		return ret;
+	}
+
 	return class_register(&firmware_class);
 }
 
@@ -1455,6 +1510,7 @@ static void __exit firmware_class_exit(void)
 	unregister_syscore_ops(&fw_syscore_ops);
 	unregister_pm_notifier(&fw_cache.pm_notify);
 #endif
+	fw_free_path_list();
 	class_unregister(&firmware_class);
 }
 
-- 
1.8.0