Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  [BLOCK] Don't allow empty barriers to be passed down to queues that don't grok them
  dm: bounce_pfn limit added
  Deadline iosched: Fix batching fairness
  Deadline iosched: Reset batch for ordered requests
  Deadline iosched: Factor out finding latter reques

block/deadline-iosched.c

@@ -55,6 +55,20 @@ static void deadline_move_request(struct deadline_data *, struct request *);
 
 #define RQ_RB_ROOT(dd, rq)	(&(dd)->sort_list[rq_data_dir((rq))])
 
+/*
+ * get the request after `rq' in sector-sorted order
+ */
+static inline struct request *
+deadline_latter_request(struct request *rq)
+{
+	struct rb_node *node = rb_next(&rq->rb_node);
+
+	if (node)
+		return rb_entry_rq(node);
+
+	return NULL;
+}
+
 static void
 deadline_add_rq_rb(struct deadline_data *dd, struct request *rq)
 {
@@ -74,13 +88,8 @@ deadline_del_rq_rb(struct deadline_data *dd, struct request *rq)
 {
 	const int data_dir = rq_data_dir(rq);
 
-	if (dd->next_rq[data_dir] == rq) {
-		struct rb_node *rbnext = rb_next(&rq->rb_node);
-
-		dd->next_rq[data_dir] = NULL;
-		if (rbnext)
-			dd->next_rq[data_dir] = rb_entry_rq(rbnext);
-	}
+	if (dd->next_rq[data_dir] == rq)
+		dd->next_rq[data_dir] = deadline_latter_request(rq);
 
 	elv_rb_del(RQ_RB_ROOT(dd, rq), rq);
 }
@@ -198,13 +207,10 @@ static void
 deadline_move_request(struct deadline_data *dd, struct request *rq)
 {
 	const int data_dir = rq_data_dir(rq);
-	struct rb_node *rbnext = rb_next(&rq->rb_node);
 
 	dd->next_rq[READ] = NULL;
 	dd->next_rq[WRITE] = NULL;
-
-	if (rbnext)
-		dd->next_rq[data_dir] = rb_entry_rq(rbnext);
+	dd->next_rq[data_dir] = deadline_latter_request(rq);
 
 	dd->last_sector = rq->sector + rq->nr_sectors;
 
@@ -301,30 +307,23 @@ static int deadline_dispatch_requests(struct request_queue *q, int force)
 	/*
 	 * we are not running a batch, find best request for selected data_dir
 	 */
-	if (deadline_check_fifo(dd, data_dir)) {
-		/* An expired request exists - satisfy it */
-		dd->batching = 0;
+	if (deadline_check_fifo(dd, data_dir) || !dd->next_rq[data_dir]) {
+		/*
+		 * A deadline has expired, the last request was in the other
+		 * direction, or we have run out of higher-sectored requests.
+		 * Start again from the request with the earliest expiry time.
+		 */
 		rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
-		
-	} else if (dd->next_rq[data_dir]) {
+	} else {
 		/*
 		 * The last req was the same dir and we have a next request in
 		 * sort order. No expired requests so continue on from here.
 		 */
 		rq = dd->next_rq[data_dir];
-	} else {
-		struct rb_node *node;
-		/*
-		 * The last req was the other direction or we have run out of
-		 * higher-sectored requests. Go back to the lowest sectored
-		 * request (1 way elevator) and start a new batch.
-		 */
-		dd->batching = 0;
-		node = rb_first(&dd->sort_list[data_dir]);
-		if (node)
-			rq = rb_entry_rq(node);
 	}
 
+	dd->batching = 0;
+
 dispatch_request:
 	/*
 	 * rq is the selected appropriate request.

block/ll_rw_blk.c

@@ -3221,6 +3221,7 @@ static inline void __generic_make_request(struct bio *bio)
 	sector_t old_sector;
 	int ret, nr_sectors = bio_sectors(bio);
 	dev_t old_dev;
+	int err = -EIO;
 
 	might_sleep();
 
@@ -3248,7 +3249,7 @@ static inline void __generic_make_request(struct bio *bio)
 				bdevname(bio->bi_bdev, b),
 				(long long) bio->bi_sector);
 end_io:
-			bio_endio(bio, -EIO);
+			bio_endio(bio, err);
 			break;
 		}
 
@@ -3283,6 +3284,10 @@ static inline void __generic_make_request(struct bio *bio)
 
 		if (bio_check_eod(bio, nr_sectors))
 			goto end_io;
+		if (bio_empty_barrier(bio) && !q->prepare_flush_fn) {
+			err = -EOPNOTSUPP;
+			goto end_io;
+		}
 
 		ret = q->make_request_fn(q, bio);
 	} while (ret);

drivers/md/dm-table.c

@@ -102,6 +102,8 @@ static void combine_restrictions_low(struct io_restrictions *lhs,
 	lhs->seg_boundary_mask =
 		min_not_zero(lhs->seg_boundary_mask, rhs->seg_boundary_mask);
 
+	lhs->bounce_pfn = min_not_zero(lhs->bounce_pfn, rhs->bounce_pfn);
+
 	lhs->no_cluster |= rhs->no_cluster;
 }
 
@@ -566,6 +568,8 @@ void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev)
 		min_not_zero(rs->seg_boundary_mask,
 			     q->seg_boundary_mask);
 
+	rs->bounce_pfn = min_not_zero(rs->bounce_pfn, q->bounce_pfn);
+
 	rs->no_cluster |= !test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
 }
 EXPORT_SYMBOL_GPL(dm_set_device_limits);
@@ -707,6 +711,8 @@ static void check_for_valid_limits(struct io_restrictions *rs)
 		rs->max_segment_size = MAX_SEGMENT_SIZE;
 	if (!rs->seg_boundary_mask)
 		rs->seg_boundary_mask = -1;
+	if (!rs->bounce_pfn)
+		rs->bounce_pfn = -1;
 }
 
 int dm_table_add_target(struct dm_table *t, const char *type,
@@ -891,6 +897,7 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q)
 	q->hardsect_size = t->limits.hardsect_size;
 	q->max_segment_size = t->limits.max_segment_size;
 	q->seg_boundary_mask = t->limits.seg_boundary_mask;
+	q->bounce_pfn = t->limits.bounce_pfn;
 	if (t->limits.no_cluster)
 		q->queue_flags &= ~(1 << QUEUE_FLAG_CLUSTER);
 	else

include/linux/device-mapper.h

@@ -116,6 +116,7 @@ struct io_restrictions {
 	unsigned short		hardsect_size;
 	unsigned int		max_segment_size;
 	unsigned long		seg_boundary_mask;
+	unsigned long		bounce_pfn;
 	unsigned char		no_cluster; /* inverted so that 0 is default */
 };