Commit 2828908d authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

drbd: refactor the backing dev max_segments calculation 



Factor out a drbd_backing_dev_max_segments helper that checks the
backing device limitation.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Reviewed-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
Tested-by: default avatarChristoph Böhmwalder <christoph.boehmwalder@linbit.com>
Link: https://lore.kernel.org/r/20240306140332.623759-4-philipp.reisner@linbit.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 342d81fd

drivers/block/drbd/drbd_nl.c

+17 −8
Original line number Diff line number Diff line
@@ -1295,30 +1295,39 @@ static void fixup_discard_support(struct drbd_device *device, struct request_que 
	}

}



/* This is the workaround for "bio would need to, but cannot, be split" */

static unsigned int drbd_backing_dev_max_segments(struct drbd_device *device)

{

	unsigned int max_segments;



	rcu_read_lock();

	max_segments = rcu_dereference(device->ldev->disk_conf)->max_bio_bvecs;

	rcu_read_unlock();



	if (!max_segments)

		return BLK_MAX_SEGMENTS;

	return max_segments;

}



static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backing_dev *bdev,

				   unsigned int max_bio_size, struct o_qlim *o)

{

	struct request_queue * const q = device->rq_queue;

	unsigned int max_hw_sectors = max_bio_size >> 9;

	unsigned int max_segments = 0;

	unsigned int max_segments = BLK_MAX_SEGMENTS;

	struct request_queue *b = NULL;

	struct disk_conf *dc;



	if (bdev) {

		b = bdev->backing_bdev->bd_disk->queue;



		max_hw_sectors = min(queue_max_hw_sectors(b), max_bio_size >> 9);

		rcu_read_lock();

		dc = rcu_dereference(device->ldev->disk_conf);

		max_segments = dc->max_bio_bvecs;

		rcu_read_unlock();

		max_segments = drbd_backing_dev_max_segments(device);



		blk_set_stacking_limits(&q->limits);

	}



	blk_queue_max_hw_sectors(q, max_hw_sectors);

	/* 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_max_segments(q, max_segments);

	blk_queue_segment_boundary(q, PAGE_SIZE-1);

	decide_on_discard_support(device, bdev);