[PATCH 3/4] nvme: fix max_discard_sectors calculation

[Christoph Hellwig]

ctrl->max_discard_sectors stores a value that is potentially based of
the DMRSL field in Identify Controller, which is in units of LBAs and
thus dependent on the Format of a namespace.

Fix this by moving the calculation of max_discard_sectors entirely
into nvme_config_discard and replacing the ctrl->max_discard_sectors
value with a local variable so that the calculation is always
namespace-specific.

Fixes: 1a86924e4f46 ("nvme: fix interpretation of DMRSL")
Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 drivers/nvme/host/core.c | 22 ++++++++++------------
 drivers/nvme/host/nvme.h |  1 -
 2 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 2d6c1f4ad7f5c8..05372bec3b7aff 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1721,20 +1721,21 @@ static void nvme_config_discard(struct gendisk *disk, struct nvme_ns *ns)
 	struct request_queue *queue = disk->queue;
 	u32 size = queue_logical_block_size(queue);
 
-	if (ctrl->dmrsl && ctrl->dmrsl <= nvme_sect_to_lba(ns, UINT_MAX))
-		ctrl->max_discard_sectors = nvme_lba_to_sect(ns, ctrl->dmrsl);
+	BUILD_BUG_ON(PAGE_SIZE / sizeof(struct nvme_dsm_range) <
+			NVME_DSM_MAX_RANGES);
 
-	if (ctrl->max_discard_sectors == 0) {
+	if (ctrl->dmrsl && ctrl->dmrsl <= nvme_sect_to_lba(ns, UINT_MAX)) {
+		blk_queue_max_discard_sectors(queue,
+				nvme_lba_to_sect(ns, ctrl->dmrsl));
+	} else if (ctrl->oncs & NVME_CTRL_ONCS_DSM) {
+		blk_queue_max_discard_sectors(queue, UINT_MAX);
+	} else {
 		blk_queue_max_discard_sectors(queue, 0);
 		return;
 	}
 
-	BUILD_BUG_ON(PAGE_SIZE / sizeof(struct nvme_dsm_range) <
-			NVME_DSM_MAX_RANGES);
-
 	queue->limits.discard_granularity = size;
 
-	blk_queue_max_discard_sectors(queue, ctrl->max_discard_sectors);
 	blk_queue_max_discard_segments(queue, ctrl->max_discard_segments);
 
 	if (ctrl->quirks & NVME_QUIRK_DEALLOCATE_ZEROES)
@@ -2870,13 +2871,10 @@ static int nvme_init_non_mdts_limits(struct nvme_ctrl *ctrl)
 	struct nvme_id_ctrl_nvm *id;
 	int ret;
 
-	if (ctrl->oncs & NVME_CTRL_ONCS_DSM) {
-		ctrl->max_discard_sectors = UINT_MAX;
+	if (ctrl->oncs & NVME_CTRL_ONCS_DSM)
 		ctrl->max_discard_segments = NVME_DSM_MAX_RANGES;
-	} else {
-		ctrl->max_discard_sectors = 0;
+	else
 		ctrl->max_discard_segments = 0;
-	}
 
 	/*
 	 * Even though NVMe spec explicitly states that MDTS is not applicable
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index f35647c470afad..d59ed2ba1c37ca 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -296,7 +296,6 @@ struct nvme_ctrl {
 	u32 max_hw_sectors;
 	u32 max_segments;
 	u32 max_integrity_segments;
-	u32 max_discard_sectors;
 	u32 max_discard_segments;
 	u32 max_zeroes_sectors;
 #ifdef CONFIG_BLK_DEV_ZONED
-- 
2.39.2