[PATCH 1/3] res_counter: introduce res_counter_write_u64()

[Li Zefan <lizf@cn.fujitsu.com>]

This function can be used to assign the value of a resource counter member.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 include/linux/res_counter.h |    9 ++++++---
 kernel/res_counter.c        |    9 +++++++++
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index 8cb1ecd..8c23f7f 100644
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -41,9 +41,10 @@ struct res_counter {
 
 /**
  * Helpers to interact with userspace
- * res_counter_read_u64() - returns the value of the specified member.
- * res_counter_read/_write - put/get the specified fields from the
- * res_counter struct to/from the user
+ * res_counter_read_64/_write_u64 - returns/assigns the value of the
+ *	specified member
+ * res_counter_read/_write - puts/gets the specified fields from the
+ *	res_counter struct to/from the user
  *
  * @counter:     the counter in question
  * @member:  the field to work with (see RES_xxx below)
@@ -53,6 +54,8 @@ struct res_counter {
  */
 
 u64 res_counter_read_u64(struct res_counter *counter, int member);
+void res_counter_write_u64(struct res_counter *counter, int member,
+			   unsigned long long val);
 
 ssize_t res_counter_read(struct res_counter *counter, int member,
 		const char __user *buf, size_t nbytes, loff_t *pos,
diff --git a/kernel/res_counter.c b/kernel/res_counter.c
index 791ff2b..a16b727 100644
--- a/kernel/res_counter.c
+++ b/kernel/res_counter.c
@@ -97,6 +97,15 @@ u64 res_counter_read_u64(struct res_counter *counter, int member)
 	return *res_counter_member(counter, member);
 }
 
+void res_counter_write_u64(struct res_counter *counter, int member,
+			   unsigned long long val)
+{
+	unsigned long long *tmp;
+
+	tmp = res_counter_member(counter, member);
+	*tmp = val;
+}
+
 ssize_t res_counter_write(struct res_counter *counter, int member,
 		const char __user *userbuf, size_t nbytes, loff_t *pos,
 		int (*write_strategy)(char *st_buf, unsigned long long *val))
-- 
1.5.4.rc3