Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index e72843f..4f2ff1b 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -227,6 +227,9 @@
 	if (*ppos < 0 || !count)
 		return -EINVAL;
 
+	if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
+		count = PAGE_SIZE << (MAX_ORDER - 1);
+
 	buf = kmalloc(count, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
@@ -371,6 +374,9 @@
 	if (*ppos < 0 || !count)
 		return -EINVAL;
 
+	if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
+		count = PAGE_SIZE << (MAX_ORDER - 1);
+
 	buf = kmalloc(count, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
@@ -457,29 +463,31 @@
 {
 	struct regmap *map = container_of(file->private_data,
 					  struct regmap, cache_only);
-	ssize_t result;
-	bool was_enabled, require_sync = false;
+	bool new_val, require_sync = false;
 	int err;
 
+	err = kstrtobool_from_user(user_buf, count, &new_val);
+	/* Ignore malforned data like debugfs_write_file_bool() */
+	if (err)
+		return count;
+
+	err = debugfs_file_get(file->f_path.dentry);
+	if (err)
+		return err;
+
 	map->lock(map->lock_arg);
 
-	was_enabled = map->cache_only;
-
-	result = debugfs_write_file_bool(file, user_buf, count, ppos);
-	if (result < 0) {
-		map->unlock(map->lock_arg);
-		return result;
-	}
-
-	if (map->cache_only && !was_enabled) {
+	if (new_val && !map->cache_only) {
 		dev_warn(map->dev, "debugfs cache_only=Y forced\n");
 		add_taint(TAINT_USER, LOCKDEP_STILL_OK);
-	} else if (!map->cache_only && was_enabled) {
+	} else if (!new_val && map->cache_only) {
 		dev_warn(map->dev, "debugfs cache_only=N forced: syncing cache\n");
 		require_sync = true;
 	}
+	map->cache_only = new_val;
 
 	map->unlock(map->lock_arg);
+	debugfs_file_put(file->f_path.dentry);
 
 	if (require_sync) {
 		err = regcache_sync(map);
@@ -487,7 +495,7 @@
 			dev_err(map->dev, "Failed to sync cache %d\n", err);
 	}
 
-	return result;
+	return count;
 }
 
 static const struct file_operations regmap_cache_only_fops = {
@@ -502,28 +510,32 @@
 {
 	struct regmap *map = container_of(file->private_data,
 					  struct regmap, cache_bypass);
-	ssize_t result;
-	bool was_enabled;
+	bool new_val;
+	int err;
+
+	err = kstrtobool_from_user(user_buf, count, &new_val);
+	/* Ignore malforned data like debugfs_write_file_bool() */
+	if (err)
+		return count;
+
+	err = debugfs_file_get(file->f_path.dentry);
+	if (err)
+		return err;
 
 	map->lock(map->lock_arg);
 
-	was_enabled = map->cache_bypass;
-
-	result = debugfs_write_file_bool(file, user_buf, count, ppos);
-	if (result < 0)
-		goto out;
-
-	if (map->cache_bypass && !was_enabled) {
+	if (new_val && !map->cache_bypass) {
 		dev_warn(map->dev, "debugfs cache_bypass=Y forced\n");
 		add_taint(TAINT_USER, LOCKDEP_STILL_OK);
-	} else if (!map->cache_bypass && was_enabled) {
+	} else if (!new_val && map->cache_bypass) {
 		dev_warn(map->dev, "debugfs cache_bypass=N forced\n");
 	}
+	map->cache_bypass = new_val;
 
-out:
 	map->unlock(map->lock_arg);
+	debugfs_file_put(file->f_path.dentry);
 
-	return result;
+	return count;
 }
 
 static const struct file_operations regmap_cache_bypass_fops = {
@@ -571,8 +583,12 @@
 		devname = dev_name(map->dev);
 
 	if (name) {
-		map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
+		if (!map->debugfs_name) {
+			map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 					      devname, name);
+			if (!map->debugfs_name)
+				return;
+		}
 		name = map->debugfs_name;
 	} else {
 		name = devname;
@@ -580,9 +596,10 @@
 
 	if (!strcmp(name, "dummy")) {
 		kfree(map->debugfs_name);
-
 		map->debugfs_name = kasprintf(GFP_KERNEL, "dummy%d",
 						dummy_index);
+		if (!map->debugfs_name)
+				return;
 		name = map->debugfs_name;
 		dummy_index++;
 	}
@@ -644,6 +661,7 @@
 		regmap_debugfs_free_dump_cache(map);
 		mutex_unlock(&map->cache_lock);
 		kfree(map->debugfs_name);
+		map->debugfs_name = NULL;
 	} else {
 		struct regmap_debugfs_node *node, *tmp;