[PATCH 1/3] nvme: add generic helper to store secret

[Chaitanya Kulkarni]

Refactor code to avoid duplication and improve maintainability:

Consolidate the shared code between the functions
nvme_ctrl_dhchap_secret_store() and
nvme_ctrl_dhchap_ctrl_secret_store(). This duplication not only
increases the likelihood of bugs but also requires additional effort for 
maintenance and testing.

Introduce a new generic helper function called
nvme_dhchap_secret_store_common() to handle the storage of the
dhchap secret. This helper function will be used by both
nvme_ctrl_dhchap_secret_store() and
nvme_ctrl_dhchap_ctrl_secret_store().

Signed-off-by: Chaitanya Kulkarni <kch at nvidia.com>
---
 drivers/nvme/host/sysfs.c | 59 ++++++++++++++++++++++++++-------------
 1 file changed, 39 insertions(+), 20 deletions(-)

diff --git a/drivers/nvme/host/sysfs.c b/drivers/nvme/host/sysfs.c
index 796e1d373b7c..9ce3b16f06da 100644
--- a/drivers/nvme/host/sysfs.c
+++ b/drivers/nvme/host/sysfs.c
@@ -418,43 +418,53 @@ static ssize_t nvme_ctrl_dhchap_secret_show(struct device *dev,
 	return sysfs_emit(buf, "%s\n", opts->dhchap_secret);
 }
 
-static ssize_t nvme_ctrl_dhchap_secret_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t count)
+static ssize_t nvme_dhchap_secret_store_common(struct nvme_ctrl *ctrl,
+		const char *buf, size_t count, bool ctrl_secret)
 {
-	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
-	struct nvmf_ctrl_options *opts = ctrl->opts;
-	char *dhchap_secret;
+	struct nvme_dhchap_key **orig_key;
+	char **dhchap_secret;
+	char *new_dhchap_secret;
+
+	if (ctrl_secret) {
+		if (!ctrl->opts->dhchap_ctrl_secret)
+			return -EINVAL;
+		dhchap_secret = &ctrl->opts->dhchap_ctrl_secret;
+		orig_key = &ctrl->ctrl_key;
+	} else {
+		if (!ctrl->opts->dhchap_secret)
+			return -EINVAL;
+		dhchap_secret = &ctrl->opts->dhchap_secret;
+		orig_key = &ctrl->host_key;
+	}
 
-	if (!ctrl->opts->dhchap_secret)
-		return -EINVAL;
 	if (count < 7)
 		return -EINVAL;
 	if (memcmp(buf, "DHHC-1:", 7))
 		return -EINVAL;
 
-	dhchap_secret = kzalloc(count + 1, GFP_KERNEL);
-	if (!dhchap_secret)
+	new_dhchap_secret = kzalloc(count + 1, GFP_KERNEL);
+	if (!new_dhchap_secret)
 		return -ENOMEM;
-	memcpy(dhchap_secret, buf, count);
+	memcpy(new_dhchap_secret, buf, count);
 	nvme_auth_stop(ctrl);
-	if (strcmp(dhchap_secret, opts->dhchap_secret)) {
-		struct nvme_dhchap_key *key, *host_key;
+	if (strcmp(new_dhchap_secret, *dhchap_secret)) {
+		struct nvme_dhchap_key *new_key, *prev_host_key;
 		int ret;
 
-		ret = nvme_auth_generate_key(dhchap_secret, &key);
+		ret = nvme_auth_generate_key(new_dhchap_secret, &new_key);
 		if (ret) {
-			kfree(dhchap_secret);
+			kfree(new_dhchap_secret);
 			return ret;
 		}
-		kfree(opts->dhchap_secret);
-		opts->dhchap_secret = dhchap_secret;
-		host_key = ctrl->host_key;
+		kfree(*dhchap_secret);
+		*dhchap_secret = new_dhchap_secret;
+		prev_host_key = *orig_key;
 		mutex_lock(&ctrl->dhchap_auth_mutex);
-		ctrl->host_key = key;
+		*orig_key = new_key;
 		mutex_unlock(&ctrl->dhchap_auth_mutex);
-		nvme_auth_free_key(host_key);
+		nvme_auth_free_key(prev_host_key);
 	} else
-		kfree(dhchap_secret);
+		kfree(new_dhchap_secret);
 	/* Start re-authentication */
 	dev_info(ctrl->device, "re-authenticating controller\n");
 	queue_work(nvme_wq, &ctrl->dhchap_auth_work);
@@ -462,6 +472,15 @@ static ssize_t nvme_ctrl_dhchap_secret_store(struct device *dev,
 	return count;
 }
 
+
+static ssize_t nvme_ctrl_dhchap_secret_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
+
+	return nvme_dhchap_secret_store_common(ctrl, buf, count, false);
+}
+
 static DEVICE_ATTR(dhchap_secret, S_IRUGO | S_IWUSR,
 	nvme_ctrl_dhchap_secret_show, nvme_ctrl_dhchap_secret_store);
 
-- 
2.40.0