[Devel] [PATCH 02/10] CGroup API files: Add res_counter_read_u64()

[menage at google.com]

Adds a function for returning the value of a resource counter member,
in a form suitable for use in a cgroup read_u64 control file method.

Signed-off-by: Paul Menage <menage at google.com>

---
 include/linux/res_counter.h |    5 ++++-
 kernel/res_counter.c        |    5 +++++
 2 files changed, 9 insertions(+), 1 deletion(-)

Index: cgroup-2.6.25-rc2-mm1/include/linux/res_counter.h
===================================================================
--- cgroup-2.6.25-rc2-mm1.orig/include/linux/res_counter.h
+++ cgroup-2.6.25-rc2-mm1/include/linux/res_counter.h
@@ -39,8 +39,9 @@ struct res_counter {
 	spinlock_t lock;
 };
 
-/*
+/**
  * 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
  *
@@ -51,6 +52,8 @@ struct res_counter {
  * @pos:     and the offset.
  */
 
+u64 res_counter_read_u64(struct res_counter *counter, int member);
+
 ssize_t res_counter_read(struct res_counter *counter, int member,
 		const char __user *buf, size_t nbytes, loff_t *pos,
 		int (*read_strategy)(unsigned long long val, char *s));
Index: cgroup-2.6.25-rc2-mm1/kernel/res_counter.c
===================================================================
--- cgroup-2.6.25-rc2-mm1.orig/kernel/res_counter.c
+++ cgroup-2.6.25-rc2-mm1/kernel/res_counter.c
@@ -92,6 +92,11 @@ ssize_t res_counter_read(struct res_coun
 			pos, buf, s - buf);
 }
 
+u64 res_counter_read_u64(struct res_counter *counter, int member)
+{
+	return *res_counter_member(counter, member);
+}
+
 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))

--
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