Merge tag 'md-3.4' of git://neil.brown.name/md

Pull md updates for 3.4 from Neil Brown:
 "Mostly tidying up code in preparation for some bigger changes next
  time.

  A few bug fixes tagged for -stable.

  Main functionality change is that some RAID10 arrays can now grow to
  use extra space that may have been made available on the individual
  devices."

Fixed up trivial conflicts with the k[un]map_atomic() cleanups in
drivers/md/bitmap.c.

* tag 'md-3.4' of git://neil.brown.name/md: (22 commits)
  md: Add judgement bb->unacked_exist in function md_ack_all_badblocks().
  md: fix clearing of the 'changed' flags for the bad blocks list.
  md/bitmap: discard CHUNK_BLOCK_SHIFT macro
  md/bitmap: remove unnecessary indirection when allocating.
  md/bitmap: remove some pointless locking.
  md/bitmap: change a 'goto' to a normal 'if' construct.
  md/bitmap: move printing of bitmap status to bitmap.c
  md/bitmap: remove some unused noise from bitmap.h
  md/raid10 - support resizing some RAID10 arrays.
  md/raid1: handle merge_bvec_fn in member devices.
  md/raid10: handle merge_bvec_fn in member devices.
  md: add proper merge_bvec handling to RAID0 and Linear.
  md: tidy up rdev_for_each usage.
  md/raid1,raid10: avoid deadlock during resync/recovery.
  md/bitmap: ensure to load bitmap when creating via sysfs.
  md: don't set md arrays to readonly on shutdown.
  md: allow re-add to failed arrays.
  md/raid5: use atomic_dec_return() instead of atomic_dec() and atomic_read().
  md: Use existed macros instead of numbers
  md/raid5: removed unused 'added_devices' variable.
  ...

1 files changed, 90 insertions, 74 deletions

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 7294bd115e34..6f31f5596e01 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -91,7 +91,7 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
 
 	if (!conf)
 		return -ENOMEM;
-	list_for_each_entry(rdev1, &mddev->disks, same_set) {
+	rdev_for_each(rdev1, mddev) {
 		pr_debug("md/raid0:%s: looking at %s\n",
 			 mdname(mddev),
 			 bdevname(rdev1->bdev, b));
@@ -102,7 +102,7 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
 		sector_div(sectors, mddev->chunk_sectors);
 		rdev1->sectors = sectors * mddev->chunk_sectors;
 
-		list_for_each_entry(rdev2, &mddev->disks, same_set) {
+		rdev_for_each(rdev2, mddev) {
 			pr_debug("md/raid0:%s:   comparing %s(%llu)"
 				 " with %s(%llu)\n",
 				 mdname(mddev),
@@ -157,7 +157,7 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
 	smallest = NULL;
 	dev = conf->devlist;
 	err = -EINVAL;
-	list_for_each_entry(rdev1, &mddev->disks, same_set) {
+	rdev_for_each(rdev1, mddev) {
 		int j = rdev1->raid_disk;
 
 		if (mddev->level == 10) {
@@ -188,16 +188,10 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
 
 		disk_stack_limits(mddev->gendisk, rdev1->bdev,
 				  rdev1->data_offset << 9);
-		/* as we don't honour merge_bvec_fn, we must never risk
-		 * violating it, so limit ->max_segments to 1, lying within
-		 * a single page.
-		 */
 
-		if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) {
-			blk_queue_max_segments(mddev->queue, 1);
-			blk_queue_segment_boundary(mddev->queue,
-						   PAGE_CACHE_SIZE - 1);
-		}
+		if (rdev1->bdev->bd_disk->queue->merge_bvec_fn)
+			conf->has_merge_bvec = 1;
+
 		if (!smallest || (rdev1->sectors < smallest->sectors))
 			smallest = rdev1;
 		cnt++;
@@ -290,8 +284,64 @@ abort:
 	return err;
 }
 
+/* Find the zone which holds a particular offset
+ * Update *sectorp to be an offset in that zone
+ */
+static struct strip_zone *find_zone(struct r0conf *conf,
+				    sector_t *sectorp)
+{
+	int i;
+	struct strip_zone *z = conf->strip_zone;
+	sector_t sector = *sectorp;
+
+	for (i = 0; i < conf->nr_strip_zones; i++)
+		if (sector < z[i].zone_end) {
+			if (i)
+				*sectorp = sector - z[i-1].zone_end;
+			return z + i;
+		}
+	BUG();
+}
+
+/*
+ * remaps the bio to the target device. we separate two flows.
+ * power 2 flow and a general flow for the sake of perfromance
+*/
+static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
+				sector_t sector, sector_t *sector_offset)
+{
+	unsigned int sect_in_chunk;
+	sector_t chunk;
+	struct r0conf *conf = mddev->private;
+	int raid_disks = conf->strip_zone[0].nb_dev;
+	unsigned int chunk_sects = mddev->chunk_sectors;
+
+	if (is_power_of_2(chunk_sects)) {
+		int chunksect_bits = ffz(~chunk_sects);
+		/* find the sector offset inside the chunk */
+		sect_in_chunk  = sector & (chunk_sects - 1);
+		sector >>= chunksect_bits;
+		/* chunk in zone */
+		chunk = *sector_offset;
+		/* quotient is the chunk in real device*/
+		sector_div(chunk, zone->nb_dev << chunksect_bits);
+	} else{
+		sect_in_chunk = sector_div(sector, chunk_sects);
+		chunk = *sector_offset;
+		sector_div(chunk, chunk_sects * zone->nb_dev);
+	}
+	/*
+	*  position the bio over the real device
+	*  real sector = chunk in device + starting of zone
+	*	+ the position in the chunk
+	*/
+	*sector_offset = (chunk * chunk_sects) + sect_in_chunk;
+	return conf->devlist[(zone - conf->strip_zone)*raid_disks
+			     + sector_div(sector, zone->nb_dev)];
+}
+
 /**
- *	raid0_mergeable_bvec -- tell bio layer if a two requests can be merged
+ *	raid0_mergeable_bvec -- tell bio layer if two requests can be merged
  *	@q: request queue
  *	@bvm: properties of new bio
  *	@biovec: the request that could be merged to it.
@@ -303,10 +353,15 @@ static int raid0_mergeable_bvec(struct request_queue *q,
 				struct bio_vec *biovec)
 {
 	struct mddev *mddev = q->queuedata;
+	struct r0conf *conf = mddev->private;
 	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
+	sector_t sector_offset = sector;
 	int max;
 	unsigned int chunk_sectors = mddev->chunk_sectors;
 	unsigned int bio_sectors = bvm->bi_size >> 9;
+	struct strip_zone *zone;
+	struct md_rdev *rdev;
+	struct request_queue *subq;
 
 	if (is_power_of_2(chunk_sectors))
 		max =  (chunk_sectors - ((sector & (chunk_sectors-1))
@@ -314,10 +369,27 @@ static int raid0_mergeable_bvec(struct request_queue *q,
 	else
 		max =  (chunk_sectors - (sector_div(sector, chunk_sectors)
 						+ bio_sectors)) << 9;
-	if (max < 0) max = 0; /* bio_add cannot handle a negative return */
+	if (max < 0)
+		max = 0; /* bio_add cannot handle a negative return */
 	if (max <= biovec->bv_len && bio_sectors == 0)
 		return biovec->bv_len;
-	else 
+	if (max < biovec->bv_len)
+		/* too small already, no need to check further */
+		return max;
+	if (!conf->has_merge_bvec)
+		return max;
+
+	/* May need to check subordinate device */
+	sector = sector_offset;
+	zone = find_zone(mddev->private, &sector_offset);
+	rdev = map_sector(mddev, zone, sector, &sector_offset);
+	subq = bdev_get_queue(rdev->bdev);
+	if (subq->merge_bvec_fn) {
+		bvm->bi_bdev = rdev->bdev;
+		bvm->bi_sector = sector_offset + zone->dev_start +
+			rdev->data_offset;
+		return min(max, subq->merge_bvec_fn(subq, bvm, biovec));
+	} else
 		return max;
 }
 
@@ -329,7 +401,7 @@ static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks
 	WARN_ONCE(sectors || raid_disks,
 		  "%s does not support generic reshape\n", __func__);
 
-	list_for_each_entry(rdev, &mddev->disks, same_set)
+	rdev_for_each(rdev, mddev)
 		array_sectors += rdev->sectors;
 
 	return array_sectors;
@@ -397,62 +469,6 @@ static int raid0_stop(struct mddev *mddev)
 	return 0;
 }
 
-/* Find the zone which holds a particular offset
- * Update *sectorp to be an offset in that zone
- */
-static struct strip_zone *find_zone(struct r0conf *conf,
-				    sector_t *sectorp)
-{
-	int i;
-	struct strip_zone *z = conf->strip_zone;
-	sector_t sector = *sectorp;
-
-	for (i = 0; i < conf->nr_strip_zones; i++)
-		if (sector < z[i].zone_end) {
-			if (i)
-				*sectorp = sector - z[i-1].zone_end;
-			return z + i;
-		}
-	BUG();
-}
-
-/*
- * remaps the bio to the target device. we separate two flows.
- * power 2 flow and a general flow for the sake of perfromance
-*/
-static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
-				sector_t sector, sector_t *sector_offset)
-{
-	unsigned int sect_in_chunk;
-	sector_t chunk;
-	struct r0conf *conf = mddev->private;
-	int raid_disks = conf->strip_zone[0].nb_dev;
-	unsigned int chunk_sects = mddev->chunk_sectors;
-
-	if (is_power_of_2(chunk_sects)) {
-		int chunksect_bits = ffz(~chunk_sects);
-		/* find the sector offset inside the chunk */
-		sect_in_chunk  = sector & (chunk_sects - 1);
-		sector >>= chunksect_bits;
-		/* chunk in zone */
-		chunk = *sector_offset;
-		/* quotient is the chunk in real device*/
-		sector_div(chunk, zone->nb_dev << chunksect_bits);
-	} else{
-		sect_in_chunk = sector_div(sector, chunk_sects);
-		chunk = *sector_offset;
-		sector_div(chunk, chunk_sects * zone->nb_dev);
-	}
-	/*
-	*  position the bio over the real device
-	*  real sector = chunk in device + starting of zone
-	*	+ the position in the chunk
-	*/
-	*sector_offset = (chunk * chunk_sects) + sect_in_chunk;
-	return conf->devlist[(zone - conf->strip_zone)*raid_disks
-			     + sector_div(sector, zone->nb_dev)];
-}
-
 /*
  * Is io distribute over 1 or more chunks ?
 */
@@ -505,7 +521,7 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio)
 	}
 
 	sector_offset = bio->bi_sector;
-	zone =  find_zone(mddev->private, &sector_offset);
+	zone = find_zone(mddev->private, &sector_offset);
 	tmp_dev = map_sector(mddev, zone, bio->bi_sector,
 			     &sector_offset);
 	bio->bi_bdev = tmp_dev->bdev;
@@ -543,7 +559,7 @@ static void *raid0_takeover_raid45(struct mddev *mddev)
 		return ERR_PTR(-EINVAL);
 	}
 
-	list_for_each_entry(rdev, &mddev->disks, same_set) {
+	rdev_for_each(rdev, mddev) {
 		/* check slot number for a disk */
 		if (rdev->raid_disk == mddev->raid_disks-1) {
 			printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n",