[patch 41/56] openmosix/mig_do_receive_cleanup.patch

[patch @num@/@total@] @name@ mig_do_receive cleanup

This patch cleans up the implementation of mig_do_receive, adding spin locks and
cleaning the structure .... 

Index: linux/hpc/migrecv.c
===================================================================
--- linux.orig/hpc/migrecv.c	2006-11-02 22:52:35.000000000 +0100
+++ linux/hpc/migrecv.c	2006-11-02 22:52:37.000000000 +0100
@@ -1,6 +1,7 @@
 /*
  *	Copyright (C) 2002-2004 Moshe Bar <moshe-ay74M1d3r6RWk0Htik3J/[email protected]>
  *	Copyright (C) 2005-2006 Vincent Hanquez <vincent-mTI/[email protected]>
+ *	Copyright (C) 2006-2007 Florian Delizy <[email protected]>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published
@@ -15,6 +16,8 @@
  *
  * Changes for 2.6 by Vincent Hanquez and Alexander Nyberg
  *
+ * Kcomd protocol by Matt Dew and Florian Delizy
+ *
  */
 
 #include <linux/sched.h>
@@ -471,7 +474,8 @@
 {
 	struct kcom_task *mytsk=NULL;
 	struct kcom_pkt *pkt, *pkt_next;
-	int ret;
+	int ret = 0;
+	int waiting_time = 0;
 
 
 	task_set_dflags(p, DINCOMING);
@@ -479,91 +483,100 @@
 
 	/* Wait for kcomd to set up the kcom_task struct*/
 	while (mytsk==NULL) {
+		waiting_time++;
 		schedule_timeout_interruptible(HZ/1000);
-	/*spin_lock();*/
 		mytsk=kcom_task_find(p->pid);
-	/*spin_unlock();*/
+		/* Preventing infinite loops */
+		if (1000000 < waiting_time) {
+			printk(KERN_ERR "openMosix: kcomd task creation timeout exceeded, dying ... \n");
+			ret = -1;
+			goto init_exit;
+		}
 	}
 
+	ret = 0;
 	/* Initialize remote proc's whereto*/
 	if (task_test_dflags(p, DREMOTE)) {
 		memcpy(p->om.whereto, &mytsk->node->addr, sizeof(mytsk->node->addr));
 	}
 
 	set_current_state(TASK_INTERRUPTIBLE);
-	/* spin_lock(&mytsk->spinlock);*/
+
+	write_lock(&mytsk->spinlock);
 	while (1) {
 
-		if (!list_empty(&mytsk->in_packs))
-			list_for_each_entry_safe(pkt, pkt_next, &mytsk->in_packs, list) {
+		if (list_empty(&mytsk->in_packs)) goto protocol_sleep;
+
+		list_for_each_entry_safe(pkt, pkt_next, &mytsk->in_packs, list) {
+
+			ret = 0;
+
+			switch (pkt->type & MIG_MASK) {
+
+				case MIG_MM:
+					ret =  mig_do_receive_mm(p, pkt);
+					break;
+
+				case MIG_VMA:
+					ret=mig_do_receive_vma(p, pkt);
+					break;
+
+				case MIG_PAGE:
+					ret=mig_do_receive_page(p, pkt);
+					break;
+
+				case MIG_FP:
+					ret=mig_do_receive_fp(p, pkt);
+					break;
+
+				/* this is the last thing we do in the chain of receiving,
+				 * so return 0 after we're done */
+				case MIG_TASK:
+					ret=mig_do_receive_proc_context(p, pkt);
+
+					task_clear_dflags(p, DINCOMING);
+					flush_tlb_mm(p->mm); /* for all the new pages */
 
-				switch (pkt->type & MIG_MASK) {
+					list_del(&pkt->list);
+					kmem_cache_free(kcom_pkt_cachep, pkt);
+					/* spin_unlock(&mytsk->spinlock);*/
 
-					case MIG_MM:
-						ret =  mig_do_receive_mm(p, pkt);
-						list_del(&pkt->list);
-						kmem_cache_free(kcom_pkt_cachep, pkt);
-						if (ret)
-							return ret;
-						break;
-
-					case MIG_VMA:
-						ret=mig_do_receive_vma(p, pkt);
-						list_del(&pkt->list);
-						kmem_cache_free(kcom_pkt_cachep, pkt);
-						if (ret)
-							return ret;
-						break;
-
-					case MIG_PAGE:
-						ret=mig_do_receive_page(p, pkt);
-						list_del(&pkt->list);
-						kmem_cache_free(kcom_pkt_cachep, pkt);
-						if (ret)
-							return ret;
-						break;
-
-					case MIG_FP:
-						ret=mig_do_receive_fp(p, pkt);
-						list_del(&pkt->list);
-						kmem_cache_free(kcom_pkt_cachep, pkt);
-						if (ret)
-							return ret;
-						break;
-
-					/* this is the last thing we do in the chain of receiving,
-					 * so return 0 after we're done */
-					case MIG_TASK:
-						ret=mig_do_receive_proc_context(p, pkt);
-
-						task_clear_dflags(p, DINCOMING);
-						flush_tlb_mm(p->mm); /* for all the new pages */
-
-						list_del(&pkt->list);
-						kmem_cache_free(kcom_pkt_cachep, pkt);
-						/* spin_unlock(&mytsk->spinlock);*/
-
-						if (ret)
-							return ret;
-						set_current_state(TASK_RUNNING);
-						return 0;
-
-					default:
-						printk(KERN_ERR "[pid: %u] Unknown packet type 0x%x received.\n", p->pid, pkt->type);
-						break;
+					if (!ret) set_current_state(TASK_RUNNING);
 
-				}
+					goto protocol_exit;
+
+					break;
+
+				default:
+					printk(KERN_ERR "openMosix: (receive) [pid: %u] Unknown packet type 0x%x received.\n", p->pid, pkt->type);
+
+					ret = -1; /* Should exit on unknown packet !! */
+					break;
 
 			}
+			list_del(&pkt->list);
+			kmem_cache_free(kcom_pkt_cachep, pkt);
+			if (ret)
+				goto protocol_exit;
 
-	/* spin_unlock(&mytsk->spinlock);*/
-	schedule();
-	set_current_state(TASK_INTERRUPTIBLE);
-	/* spin_lock(&mytsk->spinlock);*/
+		}
+
+	/* This label is inside the while, yes, but it allows much more readability ... */
+	protocol_sleep:
+		write_unlock(&mytsk->spinlock);
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule();
+		write_lock(&mytsk->spinlock);
 	}
-	/* spin_unlock(&mytsk->spinlock);*/
 
 
+protocol_exit:
+	write_unlock(&mytsk->spinlock);
+
+init_exit:
+
+	return ret;
+
 }
 
 /**
@@ -575,8 +588,9 @@
  * Description:
  *    This is the newly created process.
  **/
-KCOMD_NSTATIC NORET_TYPE int mig_handle_migration(pid_t *pid)
+KCOMD_NSTATIC NORET_TYPE int mig_handle_migration(void *param)
 {
+	pid_t *pid = (pid_t *) param;
 	task_t *p = current;
 	int error;
 
Index: linux/include/hpc/prototype.h
===================================================================
--- linux.orig/include/hpc/prototype.h	2006-11-02 22:51:23.000000000 +0100
+++ linux/include/hpc/prototype.h	2006-11-02 22:52:37.000000000 +0100
@@ -107,7 +107,7 @@
 int kcom_task_send(struct kcom_task *, int, int, char *, char *, unsigned long);
 int kcom_task_delete(int);
 
-int mig_handle_migration(int *);
+int mig_handle_migration(void *);
 int user_thread(int (*fn)(void *), void * arg, unsigned long flags);
 int mig_init(struct kcom_node *,struct kcom_pkt *);