sysctl: add proc_dointvec_ms_jiffies_minmax

add proc_dointvec_ms_jiffies_minmax to fit read msecs value to jiffies
with a limited range of values
Signed-off-by: Yuwei Wang <wangyuweihx@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

include/linux/sysctl.h

@@ -75,6 +75,8 @@ int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer,
 int proc_dou8vec_minmax(struct ctl_table *table, int write, void *buffer,
 			size_t *lenp, loff_t *ppos);
 int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos);
 int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *,
 		loff_t *);
 int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *,

kernel/sysctl.c

@@ -1237,6 +1237,30 @@ static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
 	return 0;
 }
 
+static int do_proc_dointvec_ms_jiffies_minmax_conv(bool *negp, unsigned long *lvalp,
+						int *valp, int write, void *data)
+{
+	int tmp, ret;
+	struct do_proc_dointvec_minmax_conv_param *param = data;
+	/*
+	 * If writing, first do so via a temporary local int so we can
+	 * bounds-check it before touching *valp.
+	 */
+	int *ip = write ? &tmp : valp;
+
+	ret = do_proc_dointvec_ms_jiffies_conv(negp, lvalp, ip, write, data);
+	if (ret)
+		return ret;
+
+	if (write) {
+		if ((param->min && *param->min > tmp) ||
+				(param->max && *param->max < tmp))
+			return -EINVAL;
+		*valp = tmp;
+	}
+	return 0;
+}
+
 /**
  * proc_dointvec_jiffies - read a vector of integers as seconds
  * @table: the sysctl table
@@ -1259,6 +1283,17 @@ int proc_dointvec_jiffies(struct ctl_table *table, int write,
 		    	    do_proc_dointvec_jiffies_conv,NULL);
 }
 
+int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
+			  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct do_proc_dointvec_minmax_conv_param param = {
+		.min = (int *) table->extra1,
+		.max = (int *) table->extra2,
+	};
+	return do_proc_dointvec(table, write, buffer, lenp, ppos,
+			do_proc_dointvec_ms_jiffies_minmax_conv, &param);
+}
+
 /**
  * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
  * @table: the sysctl table
@@ -1523,6 +1558,12 @@ int proc_dointvec_jiffies(struct ctl_table *table, int write,
 	return -ENOSYS;
 }
 
+int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
+				    void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
 		    void *buffer, size_t *lenp, loff_t *ppos)
 {