From 0f5cc181bee196c6f543505b96edd9d351781e96 Mon Sep 17 00:00:00 2001
From: Yufeng Mo <moyufeng@huawei.com>
Date: Wed, 30 Mar 2022 21:45:05 +0800
Subject: [PATCH 04/12] net: hns3: fix the concurrency between functions
 reading debugfs
Git-commit: 9c9a04212fa380d2e7d1412bb281309955c0a781
Patch-mainline: v5.18-rc1
References: git-fixes

Currently, the debugfs mechanism is that all functions share a
global variable to save the pointer for obtaining data. When
different functions concurrently access the same file node,
repeated release exceptions occur. Therefore, the granularity
of the pointer for storing the obtained data is adjusted to be
private for each function.

Fixes: 5e69ea7ee2a6 ("net: hns3: refactor the debugfs process")
Signed-off-by: Yufeng Mo <moyufeng@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
 drivers/net/ethernet/hisilicon/hns3/hnae3.h        |  1 +
 drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c | 15 +++++++++++----
 drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.h |  1 -
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hnae3.h b/drivers/net/ethernet/hisilicon/hns3/hnae3.h
index 69b1af059768..cb4306c67e07 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hnae3.h
+++ b/drivers/net/ethernet/hisilicon/hns3/hnae3.h
@@ -844,6 +844,7 @@ struct hnae3_handle {
 	struct dentry *hnae3_dbgfs;
 	/* protects concurrent contention between debugfs commands */
 	struct mutex dbgfs_lock;
+	char **dbgfs_buf;
 
 	/* Network interface message level enabled bits */
 	u32 msg_enable;
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
index c6072f0b817a..b1f7e9e79495 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
@@ -1227,7 +1227,7 @@ static ssize_t hns3_dbg_read(struct file *filp, char __user *buffer,
 		return ret;
 
 	mutex_lock(&handle->dbgfs_lock);
-	save_buf = &hns3_dbg_cmd[index].buf;
+	save_buf = &handle->dbgfs_buf[index];
 
 	if (!test_bit(HNS3_NIC_STATE_INITED, &priv->state) ||
 	    test_bit(HNS3_NIC_STATE_RESETTING, &priv->state)) {
@@ -1332,6 +1332,13 @@ int hns3_dbg_init(struct hnae3_handle *handle)
 	int ret;
 	u32 i;
 
+	handle->dbgfs_buf = devm_kcalloc(&handle->pdev->dev,
+					 ARRAY_SIZE(hns3_dbg_cmd),
+					 sizeof(*handle->dbgfs_buf),
+					 GFP_KERNEL);
+	if (!handle->dbgfs_buf)
+		return -ENOMEM;
+
 	hns3_dbg_dentry[HNS3_DBG_DENTRY_COMMON].dentry =
 				debugfs_create_dir(name, hns3_dbgfs_root);
 	handle->hnae3_dbgfs = hns3_dbg_dentry[HNS3_DBG_DENTRY_COMMON].dentry;
@@ -1380,9 +1387,9 @@ void hns3_dbg_uninit(struct hnae3_handle *handle)
 	u32 i;
 
 	for (i = 0; i < ARRAY_SIZE(hns3_dbg_cmd); i++)
-		if (hns3_dbg_cmd[i].buf) {
-			kvfree(hns3_dbg_cmd[i].buf);
-			hns3_dbg_cmd[i].buf = NULL;
+		if (handle->dbgfs_buf[i]) {
+			kvfree(handle->dbgfs_buf[i]);
+			handle->dbgfs_buf[i] = NULL;
 		}
 
 	mutex_destroy(&handle->dbgfs_lock);
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.h b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.h
index bd8801065e02..814f7491ca08 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.h
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.h
@@ -47,7 +47,6 @@ struct hns3_dbg_cmd_info {
 	enum hnae3_dbg_cmd cmd;
 	enum hns3_dbg_dentry_type dentry;
 	u32 buf_len;
-	char *buf;
 	int (*init)(struct hnae3_handle *handle, unsigned int cmd);
 };
 
-- 
2.16.4