# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.588   -> 1.589  
#	      kernel/ksyms.c	1.93    -> 1.94   
#	         fs/buffer.c	1.105   -> 1.106  
#	include/linux/tqueue.h	1.4     -> 1.5    
#	        mm/mempool.c	1.7     -> 1.8    
#	      mm/readahead.c	1.8     -> 1.9    
#	drivers/block/ll_rw_blk.c	1.72    -> 1.73   
#	 mm/page-writeback.c	1.18    -> 1.19   
#	         mm/vmscan.c	1.72    -> 1.73   
#	drivers/block/floppy.c	1.25    -> 1.26   
#	include/linux/blkdev.h	1.46    -> 1.47   
#	 fs/jbd/checkpoint.c	1.4     -> 1.5    
#	  include/linux/fs.h	1.123   -> 1.124  
#	     drivers/md/md.c	1.56    -> 1.57   
#	          fs/iobuf.c	1.7     -> 1.8    
#	fs/reiserfs/buffer2.c	1.13    -> 1.14   
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/05/28	axboe@burns.home.kernel.dk	1.589
# tq_disk removal and plugging reworked
# --------------------------------------------
#
diff -Nru a/drivers/block/floppy.c b/drivers/block/floppy.c
--- a/drivers/block/floppy.c	Tue May 28 10:33:57 2002
+++ b/drivers/block/floppy.c	Tue May 28 10:33:57 2002
@@ -3900,7 +3900,7 @@
 	bio.bi_end_io = floppy_rb0_complete;
 
 	submit_bio(READ, &bio);
-	run_task_queue(&tq_disk);
+	generic_unplug_device(bdev_get_queue(bdev));
 	process_fd_request();
 	wait_for_completion(&complete);
 
diff -Nru a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
--- a/drivers/block/ll_rw_blk.c	Tue May 28 10:33:57 2002
+++ b/drivers/block/ll_rw_blk.c	Tue May 28 10:33:57 2002
@@ -49,6 +49,9 @@
  */
 static kmem_cache_t *request_cachep;
 
+static struct list_head blk_plug_list;
+static spinlock_t blk_plug_lock = SPIN_LOCK_UNLOCKED;
+
 /*
  * The "disk" task queue is used to start the actual requests
  * after a plug
@@ -791,8 +794,12 @@
 	if (!elv_queue_empty(q))
 		return;
 
-	if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
-		queue_task(&q->plug_tq, &tq_disk);
+	if (test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
+		return;
+
+	spin_lock(&blk_plug_lock);
+	list_add_tail(&q->plug.list, &blk_plug_list);
+	spin_unlock(&blk_plug_lock);
 }
 
 /*
@@ -803,8 +810,13 @@
 	/*
 	 * not plugged
 	 */
-	if (!test_and_clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
+	if (!__test_and_clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
+		return;
+
+	if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags)) {
+		printk("queue was stopped\n");
 		return;
+	}
 
 	/*
 	 * was plugged, fire request_fn if queue has stuff to do
@@ -815,7 +827,7 @@
 
 /**
  * generic_unplug_device - fire a request queue
- * @q:    The &request_queue_t in question
+ * @data:    The &request_queue_t in question
  *
  * Description:
  *   Linux uses plugging to build bigger requests queues before letting
@@ -827,6 +839,16 @@
  **/
 void generic_unplug_device(void *data)
 {
+	request_queue_t *q = data;
+
+	tasklet_schedule(&q->plug.task);
+}
+
+/*
+ * the plug tasklet
+ */
+static void blk_task_run(unsigned long data)
+{
 	request_queue_t *q = (request_queue_t *) data;
 	unsigned long flags;
 
@@ -835,6 +857,49 @@
 	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
+/*
+ * clear top flag and schedule tasklet for execution
+ */
+void blk_start_queue(request_queue_t *q)
+{
+	if (test_and_clear_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
+		tasklet_enable(&q->plug.task);
+
+	tasklet_schedule(&q->plug.task);
+}
+
+/*
+ * set stop bit and disable any pending tasklet
+ */
+void blk_stop_queue(request_queue_t *q)
+{
+	if (!test_and_set_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
+		tasklet_disable(&q->plug.task);
+}
+
+/*
+ * the equivalent of the previous tq_disk run
+ */
+void blk_run_queues(void)
+{
+	struct list_head *tmp, *n;
+	unsigned long flags;
+
+	/*
+	 * we could splice to the stack prior to running
+	 */
+	spin_lock_irqsave(&blk_plug_lock, flags);
+	list_for_each_safe(tmp, n, &blk_plug_list) {
+		request_queue_t *q = list_entry(tmp, request_queue_t,plug.list);
+
+		if (!test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags)) {
+			list_del(&q->plug.list);
+			tasklet_schedule(&q->plug.task);
+		}
+	}
+	spin_unlock_irqrestore(&blk_plug_lock, flags);
+}
+
 static int __blk_cleanup_queue(struct request_list *list)
 {
 	struct list_head *head = &list->free;
@@ -974,9 +1039,6 @@
 	q->front_merge_fn      	= ll_front_merge_fn;
 	q->merge_requests_fn	= ll_merge_requests_fn;
 	q->prep_rq_fn		= NULL;
-	q->plug_tq.sync		= 0;
-	q->plug_tq.routine	= &generic_unplug_device;
-	q->plug_tq.data		= q;
 	q->queue_flags		= (1 << QUEUE_FLAG_CLUSTER);
 	q->queue_lock		= lock;
 
@@ -987,6 +1049,10 @@
 
 	blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS);
 	blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS);
+
+	INIT_LIST_HEAD(&q->plug.list);
+	tasklet_init(&q->plug.task, blk_task_run, (unsigned long) q);
+
 	return 0;
 }
 
@@ -1867,6 +1933,8 @@
 	blk_max_low_pfn = max_low_pfn;
 	blk_max_pfn = max_pfn;
 
+	INIT_LIST_HEAD(&blk_plug_list);
+
 #if defined(CONFIG_IDE) && defined(CONFIG_BLK_DEV_HD)
 	hd_init();
 #endif
@@ -1910,3 +1978,7 @@
 EXPORT_SYMBOL(blk_queue_start_tag);
 EXPORT_SYMBOL(blk_queue_end_tag);
 EXPORT_SYMBOL(blk_queue_invalidate_tags);
+
+EXPORT_SYMBOL(blk_start_queue);
+EXPORT_SYMBOL(blk_stop_queue);
+EXPORT_SYMBOL(blk_run_queues);
diff -Nru a/drivers/md/md.c b/drivers/md/md.c
--- a/drivers/md/md.c	Tue May 28 10:33:57 2002
+++ b/drivers/md/md.c	Tue May 28 10:33:57 2002
@@ -491,7 +491,7 @@
 	bio.bi_private = &event;
 	bio.bi_end_io = bi_complete;
 	submit_bio(rw, &bio);
-	run_task_queue(&tq_disk);
+	blk_run_queues();
 	wait_for_completion(&event);
 
 	return test_bit(BIO_UPTODATE, &bio.bi_flags);
@@ -2955,7 +2955,7 @@
 		run = thread->run;
 		if (run) {
 			run(thread->data);
-			run_task_queue(&tq_disk);
+			blk_run_queues();
 		}
 		if (signal_pending(current))
 			flush_curr_signals();
@@ -3411,7 +3411,7 @@
 
 		last_check = j;
 
-		run_task_queue(&tq_disk);
+		blk_run_queues();
 
 	repeat:
 		if (jiffies >= mark[last_mark] + SYNC_MARK_STEP ) {
diff -Nru a/fs/buffer.c b/fs/buffer.c
--- a/fs/buffer.c	Tue May 28 10:33:57 2002
+++ b/fs/buffer.c	Tue May 28 10:33:57 2002
@@ -138,7 +138,7 @@
 	get_bh(bh);
 	add_wait_queue(wq, &wait);
 	do {
-		run_task_queue(&tq_disk);
+		blk_run_queues();
 		set_task_state(tsk, TASK_UNINTERRUPTIBLE);
 		if (!buffer_locked(bh))
 			break;
@@ -487,7 +487,7 @@
 
 	wakeup_bdflush();
 	try_to_free_pages(zone, GFP_NOFS, 0);
-	run_task_queue(&tq_disk);
+	blk_run_queues();
 	__set_current_state(TASK_RUNNING);
 	yield();
 }
@@ -1004,7 +1004,7 @@
 	 * the reserve list is empty, we're sure there are 
 	 * async buffer heads in use.
 	 */
-	run_task_queue(&tq_disk);
+	blk_run_queues();
 
 	free_more_memory();
 	goto try_again;
@@ -2452,7 +2452,7 @@
 
 int block_sync_page(struct page *page)
 {
-	run_task_queue(&tq_disk);
+	blk_run_queues();
 	return 0;
 }
 
diff -Nru a/fs/iobuf.c b/fs/iobuf.c
--- a/fs/iobuf.c	Tue May 28 10:33:57 2002
+++ b/fs/iobuf.c	Tue May 28 10:33:57 2002
@@ -112,7 +112,7 @@
 repeat:
 	set_task_state(tsk, TASK_UNINTERRUPTIBLE);
 	if (atomic_read(&kiobuf->io_count) != 0) {
-		run_task_queue(&tq_disk);
+		blk_run_queues();
 		schedule();
 		if (atomic_read(&kiobuf->io_count) != 0)
 			goto repeat;
diff -Nru a/fs/jbd/checkpoint.c b/fs/jbd/checkpoint.c
--- a/fs/jbd/checkpoint.c	Tue May 28 10:33:57 2002
+++ b/fs/jbd/checkpoint.c	Tue May 28 10:33:57 2002
@@ -179,7 +179,7 @@
 
 	spin_unlock(&journal_datalist_lock);
 	ll_rw_block(WRITE, *batch_count, bhs);
-	run_task_queue(&tq_disk);
+	blk_run_queues();
 	spin_lock(&journal_datalist_lock);
 	for (i = 0; i < *batch_count; i++) {
 		struct buffer_head *bh = bhs[i];
diff -Nru a/fs/reiserfs/buffer2.c b/fs/reiserfs/buffer2.c
--- a/fs/reiserfs/buffer2.c	Tue May 28 10:33:57 2002
+++ b/fs/reiserfs/buffer2.c	Tue May 28 10:33:57 2002
@@ -32,7 +32,7 @@
 			bh, repeat_counter, buffer_journaled(bh) ? ' ' : '!',
 			buffer_journal_dirty(bh) ? ' ' : '!');
     }
-    run_task_queue(&tq_disk);
+    blk_run_queues();
     yield();
   }
   if (repeat_counter > 30000000) {
diff -Nru a/include/linux/blkdev.h b/include/linux/blkdev.h
--- a/include/linux/blkdev.h	Tue May 28 10:33:57 2002
+++ b/include/linux/blkdev.h	Tue May 28 10:33:57 2002
@@ -8,6 +8,7 @@
 #include <linux/list.h>
 #include <linux/pagemap.h>
 #include <linux/backing-dev.h>
+#include <linux/interrupt.h>
 
 #include <asm/scatterlist.h>
 
@@ -136,6 +137,11 @@
 	int max_depth;
 };
 
+struct blk_plug {
+	struct list_head list;
+	struct tasklet_struct task;
+};
+
 /*
  * Default nr free requests per queue, ll_rw_blk will scale it down
  * according to available RAM at init time
@@ -177,10 +183,7 @@
 	unsigned long		bounce_pfn;
 	int			bounce_gfp;
 
-	/*
-	 * This is used to remove the plug when tq_disk runs.
-	 */
-	struct tq_struct	plug_tq;
+	struct blk_plug		plug;
 
 	/*
 	 * various queue flags, see QUEUE_* below
@@ -217,6 +220,7 @@
 #define QUEUE_FLAG_PLUGGED	0	/* queue is plugged */
 #define QUEUE_FLAG_CLUSTER	1	/* cluster several segments into 1 */
 #define QUEUE_FLAG_QUEUED	2	/* uses generic tag queueing */
+#define QUEUE_FLAG_STOPPED	3	/* queue is stopped */
 
 #define blk_queue_plugged(q)	test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
 #define blk_mark_plugged(q)	set_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
@@ -303,6 +307,8 @@
 extern inline int blk_phys_contig_segment(request_queue_t *q, struct bio *, struct bio *);
 extern inline int blk_hw_contig_segment(request_queue_t *q, struct bio *, struct bio *);
 extern int block_ioctl(struct block_device *, unsigned int, unsigned long);
+extern void blk_start_queue(request_queue_t *q);
+extern void blk_stop_queue(request_queue_t *q);
 
 /*
  * get ready for proper ref counting
diff -Nru a/include/linux/fs.h b/include/linux/fs.h
--- a/include/linux/fs.h	Tue May 28 10:33:57 2002
+++ b/include/linux/fs.h	Tue May 28 10:33:57 2002
@@ -1079,6 +1079,7 @@
 extern int blkdev_put(struct block_device *, int);
 extern int bd_claim(struct block_device *, void *);
 extern void bd_release(struct block_device *);
+extern void blk_run_queues(void);
 
 /* fs/devices.c */
 extern const struct block_device_operations *get_blkfops(unsigned int);
diff -Nru a/include/linux/tqueue.h b/include/linux/tqueue.h
--- a/include/linux/tqueue.h	Tue May 28 10:33:57 2002
+++ b/include/linux/tqueue.h	Tue May 28 10:33:57 2002
@@ -66,7 +66,7 @@
 #define DECLARE_TASK_QUEUE(q)	LIST_HEAD(q)
 #define TQ_ACTIVE(q)		(!list_empty(&q))
 
-extern task_queue tq_timer, tq_immediate, tq_disk, tq_bdflush;
+extern task_queue tq_timer, tq_immediate, tq_bdflush;
 
 /*
  * To implement your own list of active bottom halfs, use the following
diff -Nru a/kernel/ksyms.c b/kernel/ksyms.c
--- a/kernel/ksyms.c	Tue May 28 10:33:57 2002
+++ b/kernel/ksyms.c	Tue May 28 10:33:57 2002
@@ -337,7 +337,6 @@
 EXPORT_SYMBOL(grok_partitions);
 EXPORT_SYMBOL(register_disk);
 EXPORT_SYMBOL(read_dev_sector);
-EXPORT_SYMBOL(tq_disk);
 EXPORT_SYMBOL(init_buffer);
 EXPORT_SYMBOL(wipe_partitions);
 
diff -Nru a/mm/mempool.c b/mm/mempool.c
--- a/mm/mempool.c	Tue May 28 10:33:57 2002
+++ b/mm/mempool.c	Tue May 28 10:33:57 2002
@@ -220,7 +220,7 @@
 	if (gfp_mask == gfp_nowait)
 		return NULL;
 
-	run_task_queue(&tq_disk);
+	blk_run_queues();
 
 	add_wait_queue_exclusive(&pool->wait, &wait);
 	set_task_state(current, TASK_UNINTERRUPTIBLE);
diff -Nru a/mm/page-writeback.c b/mm/page-writeback.c
--- a/mm/page-writeback.c	Tue May 28 10:33:57 2002
+++ b/mm/page-writeback.c	Tue May 28 10:33:57 2002
@@ -148,7 +148,7 @@
 		writeback_unlocked_inodes(&nr_to_write, WB_SYNC_NONE, NULL);
 		min_pages -= MAX_WRITEBACK_PAGES - nr_to_write;
 	} while (nr_to_write <= 0);
-	run_task_queue(&tq_disk);
+	blk_run_queues();
 }
 
 /*
@@ -206,7 +206,7 @@
 	next_jif = start_jif + wb_writeback_jifs;
 	nr_to_write = ps.nr_dirty;
 	writeback_unlocked_inodes(&nr_to_write, WB_SYNC_NONE, &oldest_jif);
-	run_task_queue(&tq_disk);
+	blk_run_queues();
 	yield();
 
 	if (time_before(next_jif, jiffies + HZ))
diff -Nru a/mm/readahead.c b/mm/readahead.c
--- a/mm/readahead.c	Tue May 28 10:33:57 2002
+++ b/mm/readahead.c	Tue May 28 10:33:57 2002
@@ -161,7 +161,7 @@
 	/*
 	 * Do this now, rather than at the next wait_on_page_locked().
 	 */
-	run_task_queue(&tq_disk);
+	blk_run_queues();
 
 	if (!list_empty(&page_pool))
 		BUG();
diff -Nru a/mm/vmscan.c b/mm/vmscan.c
--- a/mm/vmscan.c	Tue May 28 10:33:57 2002
+++ b/mm/vmscan.c	Tue May 28 10:33:57 2002
@@ -808,7 +808,7 @@
 		 * up on a more timely basis.
 		 */
 		kswapd_balance();
-		run_task_queue(&tq_disk);
+		blk_run_queues();
 	}
 }