[Devel] [PATCH RHEL7 COMMIT] proc connector: generic proc_event_connector() helper introduced

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-514.26.1.vz7.35.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-514.26.1.vz7.35.5
------>
commit b4a281062d0770311132bc2a19b6797f63abe161
Author: Stanislav Kinsburskiy <skinsbursky at virtuozzo.com>
Date:   Thu Aug 31 17:40:32 2017 +0300

    proc connector: generic proc_event_connector() helper introduced
    
    A lot of code is duplicated in proc connector events handling.
    This patch introduces generic even handler, which will be used by different
    events.
    
    Signed-off-by: Stanislav Kinsburskiy <skinsbursky at virtuozzo.com>
    Reviewed-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
---
 drivers/connector/cn_proc.c | 50 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
index 3165811..808b22a 100644
--- a/drivers/connector/cn_proc.c
+++ b/drivers/connector/cn_proc.c
@@ -64,6 +64,54 @@ static inline void get_seq(__u32 *ts, int *cpu)
 	preempt_enable();
 }
 
+static struct cn_msg *cn_msg_fill(__u8 *buffer,
+				  struct task_struct *task,
+				  int what, int cookie,
+				  bool (*fill_event)(struct proc_event *ev,
+						     struct task_struct *task,
+						     int cookie))
+{
+	struct cn_msg *msg;
+	struct proc_event *ev;
+	struct timespec ts;
+
+	msg = buffer_to_cn_msg(buffer);
+	ev = (struct proc_event *)msg->data;
+
+	get_seq(&msg->seq, &ev->cpu);
+	memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+	msg->ack = 0; /* not used */
+	msg->len = sizeof(*ev);
+	msg->flags = 0; /* not used */
+
+	memset(&ev->event_data, 0, sizeof(ev->event_data));
+	ktime_get_ts(&ts); /* get high res monotonic timestamp */
+	ev->timestamp_ns = timespec_to_ns(&ts);
+	ev->what = what;
+
+	return fill_event(ev, task, cookie) ? msg : NULL;
+}
+
+static void proc_event_connector(struct task_struct *task,
+				 int what, int cookie,
+				 bool (*fill_event)(struct proc_event *ev,
+						    struct task_struct *task,
+						    int cookie))
+{
+	struct cn_msg *msg;
+	__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
+
+	if (atomic_read(&proc_event_num_listeners) < 1)
+		return;
+
+	msg = cn_msg_fill(buffer, task, what, cookie, fill_event);
+	if (!msg)
+		return;
+
+	/*  If cn_netlink_send() failed, the data is not sent */
+	cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
+}
+
 void proc_fork_connector(struct task_struct *task)
 {
 	struct cn_msg *msg;
@@ -72,6 +120,8 @@ void proc_fork_connector(struct task_struct *task)
 	struct timespec ts;
 	struct task_struct *parent;
 
+	(void) proc_event_connector;
+
 	if (atomic_read(&proc_event_num_listeners) < 1)
 		return;