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drbd: refactor the backing dev max_segments calculation

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

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Philipp Reisner <philipp.reisner@linbit.com>
Reviewed-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Tested-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Link: https://lore.kernel.org/r/20240306140332.623759-4-philipp.reisner@linbit.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2024-03-06 15:03:28 +01:00 committed by Jens Axboe
parent 342d81fde2
commit 2828908d5c
1 changed files with 17 additions and 8 deletions
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25
drivers/block/drbd/drbd_nl.c
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@ -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);