From: Nick Piggin <piggin@cyberone.com.au>

Addition request debug to detect when we're leaking requests.



 drivers/block/as-iosched.c |    8 ++++++++
 drivers/block/ll_rw_blk.c  |   15 +++++++++++++++
 2 files changed, 23 insertions(+)

diff -puN drivers/block/ll_rw_blk.c~io-refcount-debugging drivers/block/ll_rw_blk.c
--- 25/drivers/block/ll_rw_blk.c~io-refcount-debugging	2003-10-02 02:27:35.000000000 -0700
+++ 25-akpm/drivers/block/ll_rw_blk.c	2003-10-02 02:28:19.000000000 -0700
@@ -1465,6 +1465,8 @@ static void freed_request(request_queue_
 	}
 }
 
+atomic_t global_nr_requests = ATOMIC_INIT(0);
+
 #define blkdev_free_rq(list) list_entry((list)->next, struct request, queuelist)
 /*
  * Get a free request, queue_lock must not be held
@@ -1542,6 +1544,8 @@ static struct request *get_request(reque
 	rq->data = NULL;
 	rq->sense = NULL;
 
+	atomic_inc(&global_nr_requests);
+
 out:
 	put_io_context(ioc);
 	return rq;
@@ -1772,6 +1776,9 @@ void __blk_put_request(request_queue_t *
 
 		blk_free_request(q, req);
 		freed_request(q, rw);
+
+		WARN_ON(atomic_read(&global_nr_requests) == 0);
+		atomic_dec(&global_nr_requests);
 	}
 }
 
@@ -2582,6 +2589,8 @@ int __init blk_dev_init(void)
 	return 0;
 }
 
+static atomic_t nr_io_contexts = ATOMIC_INIT(0);
+
 /*
  * IO Context helper functions
  */
@@ -2596,6 +2605,8 @@ void put_io_context(struct io_context *i
 		if (ioc->aic && ioc->aic->dtor)
 			ioc->aic->dtor(ioc->aic);
 		kfree(ioc);
+		WARN_ON(atomic_read(&nr_io_contexts) == 0);
+		atomic_dec(&nr_io_contexts);
 	}
 }
 
@@ -2636,6 +2647,10 @@ struct io_context *get_io_context(int gf
 	if (ret == NULL) {
 		ret = kmalloc(sizeof(*ret), GFP_ATOMIC);
 		if (ret) {
+			atomic_inc(&nr_io_contexts);
+			WARN_ON(atomic_read(&nr_io_contexts) ==
+				1 + nr_threads + atomic_read(&global_nr_requests));
+
 			atomic_set(&ret->refcount, 1);
 			ret->pid = tsk->pid;
 			ret->last_waited = jiffies; /* doesn't matter... */
diff -puN drivers/block/as-iosched.c~io-refcount-debugging drivers/block/as-iosched.c
--- 25/drivers/block/as-iosched.c~io-refcount-debugging	2003-10-02 02:27:35.000000000 -0700
+++ 25-akpm/drivers/block/as-iosched.c	2003-10-02 02:28:19.000000000 -0700
@@ -173,10 +173,15 @@ static kmem_cache_t *arq_pool;
 /*
  * IO Context helper functions
  */
+/* Debug */
+extern atomic_t global_nr_requests;
+static atomic_t nr_as_io_contexts = ATOMIC_INIT(0);
 
 /* Called to deallocate the as_io_context */
 static void free_as_io_context(struct as_io_context *aic)
 {
+	WARN_ON(atomic_read(&nr_as_io_contexts) == 0);
+	atomic_dec(&nr_as_io_contexts);
 	kfree(aic);
 }
 
@@ -192,6 +197,9 @@ static struct as_io_context *alloc_as_io
 
 	ret = kmalloc(sizeof(*ret), GFP_ATOMIC);
 	if (ret) {
+		atomic_inc(&nr_as_io_contexts);
+		WARN_ON(atomic_read(&nr_as_io_contexts) ==
+			1 + nr_threads + atomic_read(&global_nr_requests));
 		ret->dtor = free_as_io_context;
 		ret->exit = exit_as_io_context;
 		ret->state = 1 << AS_TASK_RUNNING;

_