Merge branch 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-…

…block

* 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-block:
  [PATCH] block/elevator.c: remove unused exports
  [PATCH] splice: fix smaller sized splice reads
  [PATCH] Don't inherit ->splice_pipe across forks
  [patch] cleanup: use blk_queue_stopped
  [PATCH] Document online io scheduler switching

Documentation/block/switching-sched.txt

@@ -0,0 +1,22 @@
+As of the Linux 2.6.10 kernel, it is now possible to change the
+IO scheduler for a given block device on the fly (thus making it possible,
+for instance, to set the CFQ scheduler for the system default, but
+set a specific device to use the anticipatory or noop schedulers - which
+can improve that device's throughput).
+
+To set a specific scheduler, simply do this:
+
+echo SCHEDNAME > /sys/block/DEV/queue/scheduler
+
+where SCHEDNAME is the name of a defined IO scheduler, and DEV is the
+device name (hda, hdb, sga, or whatever you happen to have).
+
+The list of defined schedulers can be found by simply doing
+a "cat /sys/block/DEV/queue/scheduler" - the list of valid names
+will be displayed, with the currently selected scheduler in brackets:
+
+# cat /sys/block/hda/queue/scheduler
+noop anticipatory deadline [cfq]
+# echo anticipatory > /sys/block/hda/queue/scheduler
+# cat /sys/block/hda/queue/scheduler
+noop [anticipatory] deadline cfq

block/elevator.c

@@ -895,10 +895,8 @@ ssize_t elv_iosched_show(request_queue_t *q, char *name)
 EXPORT_SYMBOL(elv_dispatch_sort);
 EXPORT_SYMBOL(elv_add_request);
 EXPORT_SYMBOL(__elv_add_request);
-EXPORT_SYMBOL(elv_requeue_request);
 EXPORT_SYMBOL(elv_next_request);
 EXPORT_SYMBOL(elv_dequeue_request);
 EXPORT_SYMBOL(elv_queue_empty);
-EXPORT_SYMBOL(elv_completed_request);
 EXPORT_SYMBOL(elevator_exit);
 EXPORT_SYMBOL(elevator_init);

block/ll_rw_blk.c

@@ -1554,7 +1554,7 @@ void blk_plug_device(request_queue_t *q)
 	 * don't plug a stopped queue, it must be paired with blk_start_queue()
 	 * which will restart the queueing
 	 */
-	if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
+	if (blk_queue_stopped(q))
 		return;
 
 	if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) {
@@ -1587,7 +1587,7 @@ EXPORT_SYMBOL(blk_remove_plug);
  */
 void __generic_unplug_device(request_queue_t *q)
 {
-	if (unlikely(test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags)))
+	if (unlikely(blk_queue_stopped(q)))
 		return;
 
 	if (!blk_remove_plug(q))

fs/splice.c

@@ -275,6 +275,15 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
 	error = 0;
 	bytes = 0;
 	for (i = 0; i < nr_pages; i++, index++) {
+		unsigned int this_len;
+
+		if (!len)
+			break;
+
+		/*
+		 * this_len is the max we'll use from this page
+		 */
+		this_len = min(len, PAGE_CACHE_SIZE - loff);
 find_page:
 		/*
 		 * lookup the page for this index
@@ -366,11 +375,13 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
 				 * force quit after adding this page
 				 */
 				nr_pages = i;
+				this_len = min(this_len, loff);
 			}
 		}
 fill_it:
 		pages[i] = page;
-		bytes += PAGE_CACHE_SIZE - loff;
+		bytes += this_len;
+		len -= this_len;
 		loff = 0;
 	}
 

kernel/fork.c

@@ -180,6 +180,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig)
 	atomic_set(&tsk->usage,2);
 	atomic_set(&tsk->fs_excl, 0);
 	tsk->btrace_seq = 0;
+	tsk->splice_pipe = NULL;
 	return tsk;
 }