From: Christoph Hellwig <hch@lst.de>
To: axboe@fb.com
Cc: ming.lei@redhat.com, linux-block@vger.kernel.org
Subject: [PATCH 2/4] block: force an unlimited segment size on queues with a virt boundary
Date: Thu, 16 May 2019 10:40:56 +0200 [thread overview]
Message-ID: <20190516084058.20678-3-hch@lst.de> (raw)
In-Reply-To: <20190516084058.20678-1-hch@lst.de>
We currently fail to update the front/back segment size in the bio when
deciding to allow an otherwise gappy segement to a device with a
virt boundary. The reason why this did not cause problems is that
devices with a virt boundary fundamentally don't use segments as we
know it and thus don't care. Make that assumption formal by forcing
an unlimited segement size in this case.
Fixes: f6970f83ef79 ("block: don't check if adjacent bvecs in one bio can be mergeable")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
---
block/blk-settings.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 3facc41476be..2ae348c101a0 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -310,6 +310,9 @@ void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
__func__, max_size);
}
+ /* see blk_queue_virt_boundary() for the explanation */
+ WARN_ON_ONCE(q->limits.virt_boundary_mask);
+
q->limits.max_segment_size = max_size;
}
EXPORT_SYMBOL(blk_queue_max_segment_size);
@@ -742,6 +745,14 @@ EXPORT_SYMBOL(blk_queue_segment_boundary);
void blk_queue_virt_boundary(struct request_queue *q, unsigned long mask)
{
q->limits.virt_boundary_mask = mask;
+
+ /*
+ * Devices that require a virtual boundary do not support scatter/gather
+ * I/O natively, but instead require a descriptor list entry for each
+ * page (which might not be idential to the Linux PAGE_SIZE). Because
+ * of that they are not limited by our notion of "segment size".
+ */
+ q->limits.max_segment_size = UINT_MAX;
}
EXPORT_SYMBOL(blk_queue_virt_boundary);
--
2.20.1
next prev parent reply other threads:[~2019-05-16 8:41 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-16 8:40 fix nr_phys_segments vs iterators accounting v2 Christoph Hellwig
2019-05-16 8:40 ` [PATCH 1/4] block: don't decrement nr_phys_segments for physically contigous segments Christoph Hellwig
2019-05-16 8:48 ` Hannes Reinecke
2019-05-16 13:17 ` Ming Lei
2019-05-17 23:02 ` Ming Lei
2019-05-20 11:11 ` Christoph Hellwig
2019-05-21 1:04 ` Ming Lei
2019-05-16 8:40 ` Christoph Hellwig [this message]
2019-05-16 8:49 ` [PATCH 2/4] block: force an unlimited segment size on queues with a virt boundary Hannes Reinecke
2019-05-16 8:40 ` [PATCH 3/4] block: remove the segment size check in bio_will_gap Christoph Hellwig
2019-05-16 8:49 ` Hannes Reinecke
2019-05-16 8:40 ` [PATCH 4/4] block: remove the bi_seg_{front,back}_size fields in struct bio Christoph Hellwig
2019-05-16 8:50 ` Hannes Reinecke
2019-05-20 11:17 ` fix nr_phys_segments vs iterators accounting v2 Christoph Hellwig
2019-05-21 1:09 ` Jens Axboe
2019-05-21 1:17 ` Ming Lei
2019-05-21 1:20 ` Jens Axboe
2019-05-21 1:29 ` Ming Lei
2019-05-21 5:11 ` Christoph Hellwig
2019-05-21 7:01 fix nr_phys_segments vs iterators accounting v3 Christoph Hellwig
2019-05-21 7:01 ` [PATCH 2/4] block: force an unlimited segment size on queues with a virt boundary Christoph Hellwig
2019-07-23 15:48 ` James Bottomley
2019-07-23 16:11 ` Christoph Hellwig
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