drbd: disable discard support if granularity > max

The discard_granularity describes the minimum unit of a discard.
If that is larger than the maximal discard size, we need to disable
discards completely.

Reviewed-by: Joel Colledge <joel.colledge@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Link: https://lore.kernel.org/r/20221109133453.51652-3-christoph.boehmwalder@linbit.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 249eba7..63f5899 100644 (file)
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1256,6 +1256,18 @@ static void fixup_write_zeroes(struct drbd_device *device, struct request_queue
                q->limits.max_write_zeroes_sectors = 0;
 }
 
+static void fixup_discard_support(struct drbd_device *device, struct request_queue *q)
+{
+       unsigned int max_discard = device->rq_queue->limits.max_discard_sectors;
+       unsigned int discard_granularity =
+               device->rq_queue->limits.discard_granularity >> SECTOR_SHIFT;
+
+       if (discard_granularity > max_discard) {
+               blk_queue_discard_granularity(q, 0);
+               blk_queue_max_discard_sectors(q, 0);
+       }
+}
+
 static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backing_dev *bdev,
                                   unsigned int max_bio_size, struct o_qlim *o)
 {
@@ -1288,6 +1300,7 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
                disk_update_readahead(device->vdisk);
        }
        fixup_write_zeroes(device, q);
+       fixup_discard_support(device, q);
 }
 
 void drbd_reconsider_queue_parameters(struct drbd_device *device, struct drbd_backing_dev *bdev, struct o_qlim *o)