[Suspend2][ 07/13] [Suspend2] Set NoFreeze flag on a userspace helper.

[Nigel Cunningham <nigel@suspend2.net>]

Set the NoFreeze flag on a userspace helper (userui or storage manager) so
that it can continue to function while we're doing I/O.

Signed-off-by: Nigel Cunningham <nigel@suspend2.net>

 kernel/power/netlink.c |   25 +++++++++++++++++++++++++
 1 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/kernel/power/netlink.c b/kernel/power/netlink.c
index 0aaf90e..7f06f7c 100644
--- a/kernel/power/netlink.c
+++ b/kernel/power/netlink.c
@@ -127,3 +127,28 @@ static void send_whether_debugging(struc
 			&is_debugging, sizeof(int));
 }
 
+/*
+ * Set the PF_NOFREEZE flag on the given process to ensure it can run whilst we
+ * are suspending.
+ */
+static int nl_set_nofreeze(struct user_helper_data *uhd, int pid)
+{
+	struct task_struct *t;
+
+	read_lock(&tasklist_lock);
+	if ((t = find_task_by_pid(pid)) == NULL) {
+		read_unlock(&tasklist_lock);
+		printk("Strange. Can't find the userspace task %d.\n", pid);
+		return -EINVAL;
+	}
+
+	t->flags |= PF_NOFREEZE;
+
+	read_unlock(&tasklist_lock);
+	uhd->pid = pid;
+
+	suspend_send_netlink_message(uhd, NETLINK_MSG_NOFREEZE_ACK, NULL, 0);
+
+	return 0;
+}
+

--
Nigel Cunningham		nigel at suspend2 dot net