From 343ac55d372f6f6d93c2c7e6a96d46e2ae889a44 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Sun, 20 Oct 2024 19:42:35 +0100
Subject: [PATCH] Implement priority donation helper function with propagation,
 w/ T

---
 src/threads/synch.c  | 16 +++++++++++++++-
 src/threads/thread.c |  6 ++++++
 src/threads/thread.h |  2 ++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/threads/synch.c b/src/threads/synch.c
index 4bf54a6..3495ca8 100644
--- a/src/threads/synch.c
+++ b/src/threads/synch.c
@@ -188,7 +188,21 @@ lock_init (struct lock *lock)
 }
 
 static void
-donate_priority (struct thread *donor, struct thread *donee);
+donate_priority (struct thread *donor, struct thread *donee) {
+  while (donee != NULL)
+    {
+      if (donor->priority <= donee->priority)
+          break;
+
+      donee->priority = donor->priority;
+      if (donee->waiting_lock == NULL)
+        donee = NULL;
+      else
+        donee = donee->waiting_lock->holder;
+    }
+
+  ready_list_reorder ();
+}
 
 /* Acquires LOCK, sleeping until it becomes available if
    necessary.  The lock must not already be held by the current
diff --git a/src/threads/thread.c b/src/threads/thread.c
index d65d7c4..b7bab5b 100644
--- a/src/threads/thread.c
+++ b/src/threads/thread.c
@@ -439,6 +439,12 @@ thread_get_recent_cpu (void)
   return 0;
 }
 
+void
+ready_list_reorder (void)
+{
+  list_sort (&ready_list, priority_more, NULL);
+}
+
 /* Idle thread.  Executes when no other thread is ready to run.
 
    The idle thread is initially put on the ready list by
diff --git a/src/threads/thread.h b/src/threads/thread.h
index 4e719a7..083a5ab 100644
--- a/src/threads/thread.h
+++ b/src/threads/thread.h
@@ -150,6 +150,8 @@ void thread_set_nice (int);
 int thread_get_recent_cpu (void);
 int thread_get_load_avg (void);
 
+void ready_list_reorder (void);
+
 /* Returns true iff the priority of the first list element's thread is greater
    than that of the second list element's thread. */
 list_less_func thread_priority_greater;