1 files changed, 83 insertions, 28 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index e24143cc204..67ffa391edc 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -865,10 +865,14 @@ static void dm_done(struct request *clone, int error, bool mapped)
 {
 	int r = error;
 	struct dm_rq_target_io *tio = clone->end_io_data;
-	dm_request_endio_fn rq_end_io = tio->ti->type->rq_end_io;
+	dm_request_endio_fn rq_end_io = NULL;
 
-	if (mapped && rq_end_io)
-		r = rq_end_io(tio->ti, clone, error, &tio->info);
+	if (tio->ti) {
+		rq_end_io = tio->ti->type->rq_end_io;
+
+		if (mapped && rq_end_io)
+			r = rq_end_io(tio->ti, clone, error, &tio->info);
+	}
 
 	if (r <= 0)
 		/* The target wants to complete the I/O */
@@ -968,22 +972,41 @@ static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti
 static sector_t max_io_len(sector_t sector, struct dm_target *ti)
 {
 	sector_t len = max_io_len_target_boundary(sector, ti);
+	sector_t offset, max_len;
 
 	/*
-	 * Does the target need to split even further ?
+	 * Does the target need to split even further?
 	 */
-	if (ti->split_io) {
-		sector_t boundary;
-		sector_t offset = dm_target_offset(ti, sector);
-		boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
-			   - offset;
-		if (len > boundary)
-			len = boundary;
+	if (ti->max_io_len) {
+		offset = dm_target_offset(ti, sector);
+		if (unlikely(ti->max_io_len & (ti->max_io_len - 1)))
+			max_len = sector_div(offset, ti->max_io_len);
+		else
+			max_len = offset & (ti->max_io_len - 1);
+		max_len = ti->max_io_len - max_len;
+
+		if (len > max_len)
+			len = max_len;
 	}
 
 	return len;
 }
 
+int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
+{
+	if (len > UINT_MAX) {
+		DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
+		      (unsigned long long)len, UINT_MAX);
+		ti->error = "Maximum size of target IO is too large";
+		return -EINVAL;
+	}
+
+	ti->max_io_len = (uint32_t) len;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
+
 static void __map_bio(struct dm_target *ti, struct bio *clone,
 		      struct dm_target_io *tio)
 {
@@ -1196,7 +1219,10 @@ static int __clone_and_map_discard(struct clone_info *ci)
 		if (!ti->num_discard_requests)
 			return -EOPNOTSUPP;
 
-		len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
+		if (!ti->split_discard_requests)
+			len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
+		else
+			len = min(ci->sector_count, max_io_len(ci->sector, ti));
 
 		__issue_target_requests(ci, ti, ti->num_discard_requests, len);
 
@@ -1566,15 +1592,6 @@ static int map_request(struct dm_target *ti, struct request *clone,
 	int r, requeued = 0;
 	struct dm_rq_target_io *tio = clone->end_io_data;
 
-	/*
-	 * Hold the md reference here for the in-flight I/O.
-	 * We can't rely on the reference count by device opener,
-	 * because the device may be closed during the request completion
-	 * when all bios are completed.
-	 * See the comment in rq_completed() too.
-	 */
-	dm_get(md);
-
 	tio->ti = ti;
 	r = ti->type->map_rq(ti, clone, &tio->info);
 	switch (r) {
@@ -1606,6 +1623,26 @@ static int map_request(struct dm_target *ti, struct request *clone,
 	return requeued;
 }
 
+static struct request *dm_start_request(struct mapped_device *md, struct request *orig)
+{
+	struct request *clone;
+
+	blk_start_request(orig);
+	clone = orig->special;
+	atomic_inc(&md->pending[rq_data_dir(clone)]);
+
+	/*
+	 * Hold the md reference here for the in-flight I/O.
+	 * We can't rely on the reference count by device opener,
+	 * because the device may be closed during the request completion
+	 * when all bios are completed.
+	 * See the comment in rq_completed() too.
+	 */
+	dm_get(md);
+
+	return clone;
+}
+
 /*
  * q->request_fn for request-based dm.
  * Called with the queue lock held.
@@ -1635,14 +1672,21 @@ static void dm_request_fn(struct request_queue *q)
 			pos = blk_rq_pos(rq);
 
 		ti = dm_table_find_target(map, pos);
-		BUG_ON(!dm_target_is_valid(ti));
+		if (!dm_target_is_valid(ti)) {
+			/*
+			 * Must perform setup, that dm_done() requires,
+			 * before calling dm_kill_unmapped_request
+			 */
+			DMERR_LIMIT("request attempted access beyond the end of device");
+			clone = dm_start_request(md, rq);
+			dm_kill_unmapped_request(clone, -EIO);
+			continue;
+		}
 
 		if (ti->type->busy && ti->type->busy(ti))
 			goto delay_and_out;
 
-		blk_start_request(rq);
-		clone = rq->special;
-		atomic_inc(&md->pending[rq_data_dir(clone)]);
+		clone = dm_start_request(md, rq);
 
 		spin_unlock(q->queue_lock);
 		if (map_request(ti, clone, md))
@@ -1662,8 +1706,6 @@ delay_and_out:
 	blk_delay_queue(q, HZ / 10);
 out:
 	dm_table_put(map);
-
-	return;
 }
 
 int dm_underlying_device_busy(struct request_queue *q)
@@ -2387,7 +2429,7 @@ static void dm_queue_flush(struct mapped_device *md)
  */
 struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
 {
-	struct dm_table *map = ERR_PTR(-EINVAL);
+	struct dm_table *live_map, *map = ERR_PTR(-EINVAL);
 	struct queue_limits limits;
 	int r;
 
@@ -2397,6 +2439,19 @@ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
 	if (!dm_suspended_md(md))
 		goto out;
 
+	/*
+	 * If the new table has no data devices, retain the existing limits.
+	 * This helps multipath with queue_if_no_path if all paths disappear,
+	 * then new I/O is queued based on these limits, and then some paths
+	 * reappear.
+	 */
+	if (dm_table_has_no_data_devices(table)) {
+		live_map = dm_get_live_table(md);
+		if (live_map)
+			limits = md->queue->limits;
+		dm_table_put(live_map);
+	}
+
 	r = dm_calculate_queue_limits(table, &limits);
 	if (r) {
 		map = ERR_PTR(r);