loop: implement REQ_OP_WRITE_ZEROES

It's identical to discard as hole punches will always leave us with
zeroes on reads.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index cc981f34e017..3bb04c1a4ba1 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -528,6 +528,7 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq)
         case REQ_OP_FLUSH:
                 return lo_req_flush(lo, rq);
         case REQ_OP_DISCARD:
+        case REQ_OP_WRITE_ZEROES:
                 return lo_discard(lo, rq, pos);
         case REQ_OP_WRITE:
                 if (lo->transfer)
@@ -826,6 +827,7 @@ static void loop_config_discard(struct loop_device *lo)
                 q->limits.discard_granularity = 0;
                 q->limits.discard_alignment = 0;
                 blk_queue_max_discard_sectors(q, 0);
+                blk_queue_max_write_zeroes_sectors(q, 0);
                 q->limits.discard_zeroes_data = 0;
                 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
                 return;
@@ -834,6 +836,7 @@ static void loop_config_discard(struct loop_device *lo)
         q->limits.discard_granularity = inode->i_sb->s_blocksize;
         q->limits.discard_alignment = 0;
         blk_queue_max_discard_sectors(q, UINT_MAX >> 9);
+        blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9);
         q->limits.discard_zeroes_data = 1;
         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
 }
@@ -1660,6 +1663,7 @@ static int loop_queue_rq(struct blk_mq_hw_ctx *hctx,
         switch (req_op(cmd->rq)) {
         case REQ_OP_FLUSH:
         case REQ_OP_DISCARD:
+        case REQ_OP_WRITE_ZEROES:
                 cmd->use_aio = false;
                 break;
         default: