From 2c6e6a18a37b905cb584eb0dda3ae482162a81ca Mon Sep 17 00:00:00 2001 From: Casey Chen Date: Mon, 11 May 2026 15:22:30 -0600 Subject: [PATCH] block: recompute nr_integrity_segments in blk_insert_cloned_request blk_insert_cloned_request() already recomputes nr_phys_segments against the bottom queue, because "the queue settings related to segment counting may differ from the original queue." The exact same reasoning applies to integrity segments: a stacked driver's underlying queue can have tighter virt_boundary_mask, seg_boundary_mask, or max_segment_size than the top queue, in which case blk_rq_count_integrity_sg() against the bottom queue produces a different count than the cached rq->nr_integrity_segments inherited from the source request by blk_rq_prep_clone(). When the cached count is lower than the bottom queue's actual count, blk_rq_map_integrity_sg() trips BUG_ON(segments > rq->nr_integrity_segments); on dispatch. The same families of stacked setups that motivated the existing nr_phys_segments recompute -- dm-multipath fanning out to nvme-rdma in particular -- can produce this. Mirror the nr_phys_segments handling: when the request carries integrity, recompute nr_integrity_segments against the bottom queue and reject the request if it exceeds the bottom queue's max_integrity_segments. blk_rq_count_integrity_sg() and queue_max_integrity_segments() are both already available via , which blk-mq.c includes. This closes a latent gap in the stacking contract and brings the integrity-segment accounting in line with the existing phys-segment accounting. Fixes: 76c313f658d2 ("blk-integrity: improved sg segment mapping") Signed-off-by: Casey Chen Reviewed-by: Christoph Hellwig Link: https://patch.msgid.link/20260511212230.27511-1-cachen@purestorage.com Signed-off-by: Jens Axboe --- block/blk-mq.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/block/blk-mq.c b/block/blk-mq.c index 4c5c16cce4f8..d0c37daf568f 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3307,6 +3307,25 @@ blk_status_t blk_insert_cloned_request(struct request *rq) return BLK_STS_IOERR; } + /* + * Integrity segment counting depends on the same queue limits + * (virt_boundary_mask, seg_boundary_mask, max_segment_size) that + * vary across stacked queues, so recompute against the bottom + * queue just like nr_phys_segments above. + */ + if (blk_integrity_rq(rq) && rq->bio) { + unsigned short max_int_segs = queue_max_integrity_segments(q); + + rq->nr_integrity_segments = + blk_rq_count_integrity_sg(rq->q, rq->bio); + if (rq->nr_integrity_segments > max_int_segs) { + printk(KERN_ERR "%s: over max integrity segments limit. (%u > %u)\n", + __func__, rq->nr_integrity_segments, + max_int_segs); + return BLK_STS_IOERR; + } + } + if (q->disk && should_fail_request(q->disk->part0, blk_rq_bytes(rq))) return BLK_STS_IOERR;