[v3,03/10] btrfs: add btrfs_read_policy_to_enum helper and refactor read policy store

Commit Message

Anand Jain Nov. 15, 2024, 2:54 p.m. UTC

Introduce the `btrfs_read_policy_to_enum` helper function to simplify the
conversion of a string read policy to its corresponding enum value. This
reduces duplication and improves code clarity in `btrfs_read_policy_store`.
The `btrfs_read_policy_store` function has been refactored to use the new
helper.

The parameter is copied locally to allow modification, enabling the
separation of the method and its value. This prepares for the addition of
more functionality in subsequent patches.

Signed-off-by: Anand Jain <[e-mail]>
---
 fs/btrfs/sysfs.c | 50 ++++++++++++++++++++++++++++++++++++------------
 1 file changed, 38 insertions(+), 12 deletions(-)

Patch

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index fd3c49c6c3c5..7506818ec45f 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -1307,6 +1307,34 @@  BTRFS_ATTR(, temp_fsid, btrfs_temp_fsid_show);
 
 static const char * const btrfs_read_policy_name[] = { "pid" };
 
+static enum btrfs_read_policy btrfs_read_policy_to_enum(const char *str)
+{
+	bool found = false;
+	enum btrfs_read_policy index;
+	char *param;
+
+	if (!str || !strlen(str))
+		return 0;
+
+	param = kstrdup(str, GFP_KERNEL);
+	if (!param)
+		return -ENOMEM;
+
+	for (index = 0; index < BTRFS_NR_READ_POLICY; index++) {
+		if (sysfs_streq(param, btrfs_read_policy_name[index])) {
+			found = true;
+			break;
+		}
+	}
+
+	kfree(param);
+
+	if (found)
+		return index;
+
+	return -EINVAL;
+}
+
 static ssize_t btrfs_read_policy_show(struct kobject *kobj,
 				      struct kobj_attribute *a, char *buf)
 {
@@ -1338,21 +1366,19 @@  static ssize_t btrfs_read_policy_store(struct kobject *kobj,
 				       const char *buf, size_t len)
 {
 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
-	int i;
+	enum btrfs_read_policy index;
 
-	for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
-		if (sysfs_streq(buf, btrfs_read_policy_name[i])) {
-			if (i != READ_ONCE(fs_devices->read_policy)) {
-				WRITE_ONCE(fs_devices->read_policy, i);
-				btrfs_info(fs_devices->fs_info,
-					   "read policy set to '%s'",
-					   btrfs_read_policy_name[i]);
-			}
-			return len;
-		}
+	index = btrfs_read_policy_to_enum(buf);
+	if (index == -EINVAL)
+		return -EINVAL;
+
+	if (index != READ_ONCE(fs_devices->read_policy)) {
+		WRITE_ONCE(fs_devices->read_policy, index);
+		btrfs_info(fs_devices->fs_info, "read policy set to '%s'",
+			   btrfs_read_policy_name[index]);
 	}
 
-	return -EINVAL;
+	return len;
 }
 BTRFS_ATTR_RW(, read_policy, btrfs_read_policy_show, btrfs_read_policy_store);