Merge branch 'for-linus' of git://neil.brown.name/md

* 'for-linus' of git://neil.brown.name/md:
  md: deal with merge_bvec_fn in component devices better.

1 files changed, 17 insertions, 11 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 7584f9ab9bc..b4ba41ecbd2 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1155,13 +1155,17 @@ static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 
 			disk_stack_limits(mddev->gendisk, rdev->bdev,
 					  rdev->data_offset << 9);
-			/* as we don't honour merge_bvec_fn, we must never risk
-			 * violating it, so limit ->max_sector to one PAGE, as
-			 * a one page request is never in violation.
+			/* as we don't honour merge_bvec_fn, we must
+			 * never risk violating it, so limit
+			 * ->max_segments to one lying with a single
+			 * page, as a one page request is never in
+			 * violation.
 			 */
-			if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
-			    queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
-				blk_queue_max_hw_sectors(mddev->queue, PAGE_SIZE>>9);
+			if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
+				blk_queue_max_segments(mddev->queue, 1);
+				blk_queue_segment_boundary(mddev->queue,
+							   PAGE_CACHE_SIZE - 1);
+			}
 
 			p->head_position = 0;
 			rdev->raid_disk = mirror;
@@ -2255,12 +2259,14 @@ static int run(mddev_t *mddev)
 		disk_stack_limits(mddev->gendisk, rdev->bdev,
 				  rdev->data_offset << 9);
 		/* as we don't honour merge_bvec_fn, we must never risk
-		 * violating it, so limit ->max_sector to one PAGE, as
-		 * a one page request is never in violation.
+		 * violating it, so limit max_segments to 1 lying
+		 * within a single page.
 		 */
-		if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
-		    queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
-			blk_queue_max_hw_sectors(mddev->queue, PAGE_SIZE>>9);
+		if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
+			blk_queue_max_segments(mddev->queue, 1);
+			blk_queue_segment_boundary(mddev->queue,
+						   PAGE_CACHE_SIZE - 1);
+		}
 
 		disk->head_position = 0;
 	}