[PATCH 2/5] xen/sched: create public function for cpupools creation

[Luca Fancellu <luca.fancellu@xxxxxxx>]

Create new public function to create cpupools, it checks for pool id
uniqueness before creating the pool and can take a scheduler id or
a negative value that means the default Xen scheduler will be used.

Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
---
 xen/common/sched/cpupool.c | 26 ++++++++++++++++++++++++++
 xen/include/xen/sched.h    | 17 +++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/xen/common/sched/cpupool.c b/xen/common/sched/cpupool.c
index 8c6e6eb9ccd5..4da12528d6b9 100644
--- a/xen/common/sched/cpupool.c
+++ b/xen/common/sched/cpupool.c
@@ -1218,6 +1218,32 @@ static void cpupool_hypfs_init(void)
 
 #endif /* CONFIG_HYPFS */
 
+struct cpupool *__init cpupool_create_pool(unsigned int pool_id, int sched_id)
+{
+    struct cpupool *pool;
+
+    ASSERT(!spin_is_locked(&cpupool_lock));
+
+    spin_lock(&cpupool_lock);
+    /* Check if a cpupool with pool_id exists */
+    pool = __cpupool_find_by_id(pool_id, true);
+    spin_unlock(&cpupool_lock);
+
+    /* Pool exists, return an error */
+    if ( pool )
+        return NULL;
+
+    if ( sched_id < 0 )
+        sched_id = scheduler_get_default()->sched_id;
+
+    pool = cpupool_create(pool_id, sched_id);
+
+    BUG_ON(IS_ERR(pool));
+    cpupool_put(pool);
+
+    return pool;
+}
+
 static int __init cpupool_init(void)
 {
     unsigned int cpu;
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 37f78cc4c4c9..a50df1bccdc0 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -1145,6 +1145,23 @@ int cpupool_move_domain(struct domain *d, struct cpupool 
*c);
 int cpupool_do_sysctl(struct xen_sysctl_cpupool_op *op);
 unsigned int cpupool_get_id(const struct domain *d);
 const cpumask_t *cpupool_valid_cpus(const struct cpupool *pool);
+
+/*
+ * cpupool_create_pool - Creates a cpupool
+ * @pool_id: id of the pool to be created
+ * @sched_id: id of the scheduler to be used for the pool
+ *
+ * Creates a cpupool with pool_id id, the id must be unique and the function
+ * will return an error if the pool id exists.
+ * The sched_id parameter identifies the scheduler to be used, if it is
+ * negative, the default scheduler of Xen will be used.
+ *
+ * returns:
+ *     pointer to the struct cpupool just created, on success
+ *     NULL, on cpupool creation error
+ */
+struct cpupool *cpupool_create_pool(unsigned int pool_id, int sched_id);
+
 extern void dump_runq(unsigned char key);
 
 void arch_do_physinfo(struct xen_sysctl_physinfo *pi);
-- 
2.17.1