[PATCH 11/12] Add members file support to RGCS

[Chandra Seetharaman <sekharan@us.ibm.com>]

11/12 - user_interface_members

Adds attr_store and attr_show support for members file.
--

Signed-Off-By: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-Off-By: Shailabh Nagar <nagar@watson.ibm.com>
Signed-Off-By: Matt Helsley <matthltc@us.ibm.com>

 rgcs.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 49 insertions(+)

Index: linux-2617-rc3/kernel/res_group/rgcs.c
===================================================================
--- linux-2617-rc3.orig/kernel/res_group/rgcs.c	2006-04-27 10:18:47.000000000 -0700
+++ linux-2617-rc3/kernel/res_group/rgcs.c	2006-04-27 10:18:47.000000000 -0700
@@ -242,6 +242,43 @@ static ssize_t show_shares(struct resour
 	return rc;
 }
 
+/*
+ * Given a buffer with a pid in it, add the task with that pid to the
+ * resource group. Ignores entire buffer after the first pid is parsed.
+ */
+static int add_member(struct resource_group *rgroup, const char *str)
+{
+	pid_t pid;
+
+	pid = (pid_t) simple_strtol(str, NULL, 0);
+	if (pid <= 0)
+		return -EINVAL; /* Not a valid pid */
+	return set_res_group(pid, rgroup);
+}
+
+/*
+ * Lists pids of tasks that belong to the given rgroup.
+ */
+static ssize_t show_members(struct resource_group *rgroup, char *buf)
+{
+	ssize_t i, rc = 0, bufsize = PAGE_SIZE;
+	struct task_struct *tsk;
+
+	spin_lock(&rgroup->group_lock);
+	list_for_each_entry(tsk, &rgroup->task_list, member_list) {
+		if (bufsize <= 0) {
+			rc = -ENOSPC;
+			break;
+		}
+		if (!tsk->pid)	/* Ignore swappers */
+			continue;
+		i = snprintf(buf, bufsize, "%ld\n", (long)tsk->pid);
+		buf += i; rc += i; bufsize -= i;
+	}
+	spin_unlock(&rgroup->group_lock);
+	return rc;
+}
+
 struct rgroup_attribute {
 	struct configfs_attribute configfs_attr;
 	ssize_t (*show)(struct resource_group *, char *);
@@ -268,6 +305,17 @@ struct rgroup_attribute shares_attr = {
 	.store = set_shares
 };
 
+struct rgroup_attribute members_attr = {
+	.configfs_attr = {
+		.ca_name = "members",
+		.ca_owner = THIS_MODULE,
+		.ca_mode = S_IRUGO | S_IWUSR
+	},
+	.show = show_members,
+	.store = add_member
+};
+
+
 static struct configfs_subsystem rgcs_subsys;
 static struct config_item_type rgcs_item_type;
 
@@ -417,6 +465,7 @@ static struct configfs_group_operations 
 static struct configfs_attribute *rgroup_attrs[] = {
 	&stats_attr.configfs_attr,
 	&shares_attr.configfs_attr,
+	&members_attr.configfs_attr,
 	NULL
 };
 

-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------