nvme: fix interpretation of DMRSL

DMRSLl is in the unit of logical blocks, while max_discard_sectors is
in the unit of "linux sector".
Signed-off-by: NTom Yan <tom.ty89@gmail.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

drivers/nvme/host/core.c

@@ -1634,6 +1634,9 @@ static void nvme_config_discard(struct gendisk *disk, struct nvme_ns *ns)
 	if (queue->limits.max_discard_sectors)
 		return;
 
+	if (ctrl->dmrsl && ctrl->dmrsl <= nvme_sect_to_lba(ns, UINT_MAX))
+		ctrl->max_discard_sectors = nvme_lba_to_sect(ns, ctrl->dmrsl);
+
 	blk_queue_max_discard_sectors(queue, ctrl->max_discard_sectors);
 	blk_queue_max_discard_segments(queue, ctrl->max_discard_segments);
 
@@ -2893,8 +2896,7 @@ static int nvme_init_non_mdts_limits(struct nvme_ctrl *ctrl)
 
 	if (id->dmrl)
 		ctrl->max_discard_segments = id->dmrl;
-	if (id->dmrsl)
-		ctrl->max_discard_sectors = le32_to_cpu(id->dmrsl);
+	ctrl->dmrsl = le32_to_cpu(id->dmrsl);
 	if (id->wzsl)
 		ctrl->max_zeroes_sectors = nvme_mps_to_sectors(ctrl, id->wzsl);
 

drivers/nvme/host/nvme.h

@@ -284,6 +284,7 @@ struct nvme_ctrl {
 #endif
 	u16 crdt[3];
 	u16 oncs;
+	u32 dmrsl;
 	u16 oacs;
 	u16 sqsize;
 	u32 max_namespaces;