scsi: target: iscsi: Switch to kmemdup_nul()

Use kmemdup_nul() helper instead of open-coding to simplify the code.

Link: https://lore.kernel.org/r/20210402092517.2445595-1-yangyingliang@huawei.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/iscsi/iscsi_target_nego.c

@@ -1082,14 +1082,12 @@ int iscsi_target_locate_portal(
 	login_req = (struct iscsi_login_req *) login->req;
 	payload_length = ntoh24(login_req->dlength);
 
-	tmpbuf = kzalloc(payload_length + 1, GFP_KERNEL);
+	tmpbuf = kmemdup_nul(login->req_buf, payload_length, GFP_KERNEL);
 	if (!tmpbuf) {
 		pr_err("Unable to allocate memory for tmpbuf.\n");
 		return -1;
 	}
 
-	memcpy(tmpbuf, login->req_buf, payload_length);
-	tmpbuf[payload_length] = '\0';
 	start = tmpbuf;
 	end = (start + payload_length);
 

drivers/target/iscsi/iscsi_target_parameters.c

@@ -1357,14 +1357,12 @@ int iscsi_decode_text_input(
 	struct iscsi_param_list *param_list = conn->param_list;
 	char *tmpbuf, *start = NULL, *end = NULL;
 
-	tmpbuf = kzalloc(length + 1, GFP_KERNEL);
+	tmpbuf = kmemdup_nul(textbuf, length, GFP_KERNEL);
 	if (!tmpbuf) {
 		pr_err("Unable to allocate %u + 1 bytes for tmpbuf.\n", length);
 		return -ENOMEM;
 	}
 
-	memcpy(tmpbuf, textbuf, length);
-	tmpbuf[length] = '\0';
 	start = tmpbuf;
 	end = (start + length);