[PATCH 07/27] drbd: cleanup decide_on_discard_support

Christoph Hellwig
2022-04-09T04:51:59Z

Sanitize the calling conventions and use a goto label to cleanup the
code flow.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
---
drivers/block/drbd/drbd_nl.c | 68 +++++++++++++++++++-----------------
1 file changed, 35 insertions(+), 33 deletions(-)

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 02030c9c4d3b1..40bb0b356a6d6 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1204,38 +1204,42 @@ static unsigned int drbd_max_discard_sectors(struct drbd_connection *connection)
}

static void decide_on_discard_support(struct drbd_device *device,
- struct request_queue *q,
- struct request_queue *b,
- bool discard_zeroes_if_aligned)
+ struct drbd_backing_dev *bdev)
{
- /* q = drbd device queue (device->rq_queue)
- * b = backing device queue (device->ldev->backing_bdev->bd_disk->queue),
- * or NULL if diskless
- */
- struct drbd_connection *connection = first_peer_device(device)->connection;
- bool can_do = b ? blk_queue_discard(b) : true;
-
- if (can_do && connection->cstate >= C_CONNECTED && !(connection->agreed_features & DRBD_FF_TRIM)) {
- can_do = false;
- drbd_info(connection, "peer DRBD too old, does not support TRIM: disabling discards\n");
- }
- if (can_do) {
- /* We don't care for the granularity, really.
- * Stacking limits below should fix it for the local
- * device. Whether or not it is a suitable granularity
- * on the remote device is not our problem, really. If
- * you care, you need to use devices with similar
- * topology on all peers. */
- blk_queue_discard_granularity(q, 512);
- q->limits.max_discard_sectors = drbd_max_discard_sectors(connection);
- blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
- q->limits.max_write_zeroes_sectors = drbd_max_discard_sectors(connection);
- } else {
- blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q);
- blk_queue_discard_granularity(q, 0);
- q->limits.max_discard_sectors = 0;
- q->limits.max_write_zeroes_sectors = 0;
+ struct drbd_connection *connection =
+ first_peer_device(device)->connection;
+ struct request_queue *q = device->rq_queue;
+
+ if (bdev && !blk_queue_discard(bdev->backing_bdev->bd_disk->queue))
+ goto not_supported;
+
+ if (connection->cstate >= C_CONNECTED &&
+ !(connection->agreed_features & DRBD_FF_TRIM)) {
+ drbd_info(connection,
+ "peer DRBD too old, does not support TRIM: disabling discards\n");
+ goto not_supported;
}
+
+ /*
+ * We don't care for the granularity, really.
+ *
+ * Stacking limits below should fix it for the local device. Whether or
+ * not it is a suitable granularity on the remote device is not our
+ * problem, really. If you care, you need to use devices with similar
+ * topology on all peers.
+ */
+ blk_queue_discard_granularity(q, 512);
+ q->limits.max_discard_sectors = drbd_max_discard_sectors(connection);
+ blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
+ q->limits.max_write_zeroes_sectors =
+ drbd_max_discard_sectors(connection);
+ return;
+
+not_supported:
+ blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q);
+ blk_queue_discard_granularity(q, 0);
+ q->limits.max_discard_sectors = 0;
+ q->limits.max_write_zeroes_sectors = 0;
}

static void fixup_discard_if_not_supported(struct request_queue *q)
@@ -1273,7 +1277,6 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
unsigned int max_segments = 0;
struct request_queue *b = NULL;
struct disk_conf *dc;
- bool discard_zeroes_if_aligned = true;

if (bdev) {
b = bdev->backing_bdev->bd_disk->queue;
@@ -1282,7 +1285,6 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
rcu_read_lock();
dc = rcu_dereference(device->ldev->disk_conf);
max_segments = dc->max_bio_bvecs;
- discard_zeroes_if_aligned = dc->discard_zeroes_if_aligned;
rcu_read_unlock();

blk_set_stacking_limits(&q->limits);
@@ -1292,7 +1294,7 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
/* This is the workaround for "bio would need to, but cannot, be split" */
blk_queue_max_segments(q, max_segments ? max_segments : BLK_MAX_SEGMENTS);
blk_queue_segment_boundary(q, PAGE_SIZE-1);
- decide_on_discard_support(device, q, b, discard_zeroes_if_aligned);
+ decide_on_discard_support(device, bdev);

if (b) {
blk_stack_limits(&q->limits, &b->limits, 0);
--
2.30.2