[PATCH 5.16 080/285] scsi: hisi_sas: Limit users changing debugfs BIST count value

Greg Kroah-Hartman
2022-04-12T07:45:51Z

From: Xiang Chen <chenxiang66@hisilicon.com>

[ Upstream commit 286ce4c65fbdf5eb9d4d5f4e4997c4e32bf1b073 ]

Add a file operation for "cnt" file under bist directory, so users can only
read "cnt" or clear "cnt" to zero, but cannot randomly modify.

Link: https://lore.kernel.org/r/1645703489-87194-6-git-send-email-john.garry@huawei.com
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: Qi Liu <liuqi115@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 52 +++++++++++++++++++++++++-
1 file changed, 50 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
index 8392463d57de..20763f187886 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
@@ -3968,6 +3968,54 @@ static const struct file_operations debugfs_bist_phy_v3_hw_fops = {
.owner = THIS_MODULE,
};

+static ssize_t debugfs_bist_cnt_v3_hw_write(struct file *filp,
+ const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct seq_file *m = filp->private_data;
+ struct hisi_hba *hisi_hba = m->private;
+ unsigned int cnt;
+ int val;
+
+ if (hisi_hba->debugfs_bist_enable)
+ return -EPERM;
+
+ val = kstrtouint_from_user(buf, count, 0, &cnt);
+ if (val)
+ return val;
+
+ if (cnt)
+ return -EINVAL;
+
+ hisi_hba->debugfs_bist_cnt = 0;
+ return count;
+}
+
+static int debugfs_bist_cnt_v3_hw_show(struct seq_file *s, void *p)
+{
+ struct hisi_hba *hisi_hba = s->private;
+
+ seq_printf(s, "%u\n", hisi_hba->debugfs_bist_cnt);
+
+ return 0;
+}
+
+static int debugfs_bist_cnt_v3_hw_open(struct inode *inode,
+ struct file *filp)
+{
+ return single_open(filp, debugfs_bist_cnt_v3_hw_show,
+ inode->i_private);
+}
+
+static const struct file_operations debugfs_bist_cnt_v3_hw_ops = {
+ .open = debugfs_bist_cnt_v3_hw_open,
+ .read = seq_read,
+ .write = debugfs_bist_cnt_v3_hw_write,
+ .llseek = seq_lseek,
+ .release = single_release,
+ .owner = THIS_MODULE,
+};
+
static const struct {
int value;
char *name;
@@ -4605,8 +4653,8 @@ static void debugfs_bist_init_v3_hw(struct hisi_hba *hisi_hba)
debugfs_create_file("phy_id", 0600, hisi_hba->debugfs_bist_dentry,
hisi_hba, &debugfs_bist_phy_v3_hw_fops);

- debugfs_create_u32("cnt", 0600, hisi_hba->debugfs_bist_dentry,
- &hisi_hba->debugfs_bist_cnt);
+ debugfs_create_file("cnt", 0600, hisi_hba->debugfs_bist_dentry,
+ hisi_hba, &debugfs_bist_cnt_v3_hw_ops);

debugfs_create_file("loopback_mode", 0600,
hisi_hba->debugfs_bist_dentry,
--
2.35.1