Bjoern's Dissertation Code with Priority Donationwip-splitting-omlp-jerickso

1 files changed, 186 insertions, 0 deletions

diff --git a/litmus/locking.c b/litmus/locking.c
new file mode 100644
index 000000000000..84a1d8309699
--- /dev/null
+++ b/litmus/locking.c
@@ -0,0 +1,186 @@
+#include <linux/sched.h>
+#include <litmus/litmus.h>
+#include <litmus/fdso.h>
+
+#ifdef CONFIG_LITMUS_LOCKING
+
+#include <litmus/sched_plugin.h>
+#include <litmus/trace.h>
+#include <litmus/wait.h>
+
+static int create_generic_lock(void** obj_ref, obj_type_t type, void* __user arg);
+static int open_generic_lock(struct od_table_entry* entry, void* __user arg);
+static int close_generic_lock(struct od_table_entry* entry);
+static void destroy_generic_lock(obj_type_t type, void* sem);
+
+struct fdso_ops generic_lock_ops = {
+        .create  = create_generic_lock,
+        .open    = open_generic_lock,
+        .close   = close_generic_lock,
+        .destroy = destroy_generic_lock
+};
+
+static inline bool is_lock(struct od_table_entry* entry)
+{
+        return entry->class == &generic_lock_ops;
+}
+
+static inline struct litmus_lock* get_lock(struct od_table_entry* entry)
+{
+        BUG_ON(!is_lock(entry));
+        return (struct litmus_lock*) entry->obj->obj;
+}
+
+static  int create_generic_lock(void** obj_ref, obj_type_t type, void* __user arg)
+{
+        struct litmus_lock* lock;
+        int err;
+
+        err = litmus->allocate_lock(&lock, type, arg);
+        if (err == 0)
+                *obj_ref = lock;
+        return err;
+}
+
+static int open_generic_lock(struct od_table_entry* entry, void* __user arg)
+{
+        struct litmus_lock* lock = get_lock(entry);
+        if (lock->ops->open)
+                return lock->ops->open(lock, arg);
+        else
+                return 0; /* default: any task can open it */
+}
+
+static int close_generic_lock(struct od_table_entry* entry)
+{
+        struct litmus_lock* lock = get_lock(entry);
+        if (lock->ops->close)
+                return lock->ops->close(lock);
+        else
+                return 0; /* default: closing succeeds */
+}
+
+static void destroy_generic_lock(obj_type_t type, void* obj)
+{
+        struct litmus_lock* lock = (struct litmus_lock*) obj;
+        lock->ops->deallocate(lock);
+}
+
+asmlinkage long sys_litmus_lock(int lock_od)
+{
+        long err = -EINVAL;
+        struct od_table_entry* entry;
+        struct litmus_lock* l;
+
+        TS_SYSCALL_IN_START;
+
+        TS_SYSCALL_IN_END;
+
+        TS_LOCK_START;
+
+        entry = get_entry_for_od(lock_od);
+        if (entry && is_lock(entry)) {
+                l = get_lock(entry);
+                TRACE_CUR("attempts to lock 0x%p\n", l);
+                err = l->ops->lock(l);
+        }
+
+        /* Note: task my have been suspended or preempted in between!  Take
+         * this into account when computing overheads. */
+        TS_LOCK_END;
+
+        TS_SYSCALL_OUT_START;
+
+        return err;
+}
+
+asmlinkage long sys_litmus_unlock(int lock_od)
+{
+        long err = -EINVAL;
+        struct od_table_entry* entry;
+        struct litmus_lock* l;
+
+        TS_SYSCALL_IN_START;
+
+        TS_SYSCALL_IN_END;
+
+        TS_UNLOCK_START;
+
+        entry = get_entry_for_od(lock_od);
+        if (entry && is_lock(entry)) {
+                l = get_lock(entry);
+                TRACE_CUR("attempts to unlock 0x%p\n", l);
+                err = l->ops->unlock(l);
+        }
+
+        /* Note: task my have been preempted in between!  Take this into
+         * account when computing overheads. */
+        TS_UNLOCK_END;
+
+        TS_SYSCALL_OUT_START;
+
+        return err;
+}
+
+struct task_struct* __waitqueue_remove_first(wait_queue_head_t *wq)
+{
+        wait_queue_t* q;
+        struct task_struct* t = NULL;
+
+        if (waitqueue_active(wq)) {
+                q = list_entry(wq->task_list.next,
+                               wait_queue_t, task_list);
+                t = (struct task_struct*) q->private;
+                __remove_wait_queue(wq, q);
+        }
+        return(t);
+}
+
+unsigned int __add_wait_queue_prio_exclusive(
+        wait_queue_head_t* head,
+        prio_wait_queue_t *new)
+{
+        struct list_head *pos;
+        unsigned int passed = 0;
+
+        new->wq.flags |= WQ_FLAG_EXCLUSIVE;
+
+        /* find a spot where the new entry is less than the next */
+        list_for_each(pos, &head->task_list) {
+                prio_wait_queue_t* queued = list_entry(pos, prio_wait_queue_t,
+                                                       wq.task_list);
+
+                if (unlikely(lt_before(new->priority, queued->priority) ||
+                             (new->priority == queued->priority &&
+                              new->tie_breaker < queued->tie_breaker))) {
+                        /* pos is not less than new, thus insert here */
+                        __list_add(&new->wq.task_list, pos->prev, pos);
+                        goto out;
+                }
+                passed++;
+        }
+
+        /* if we get to this point either the list is empty or every entry
+         * queued element is less than new.
+         * Let's add new to the end. */
+        list_add_tail(&new->wq.task_list, &head->task_list);
+out:
+        return passed;
+}
+
+
+#else
+
+struct fdso_ops generic_lock_ops = {};
+
+asmlinkage long sys_litmus_lock(int sem_od)
+{
+        return -ENOSYS;
+}
+
+asmlinkage long sys_litmus_unlock(int sem_od)
+{
+        return -ENOSYS;
+}
+
+#endif