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nvme-loop: don't BUG() if a scan runs beside a reset

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A reset sets queue_count to 1 while it destroys the I/O queues and
counts it back up when the new ones are made, and it doesn't stop the
scan work. A new namespace found in that window trips the check in
nvme_loop_init_hctx() for every hctx but the first:

  kernel BUG at drivers/nvme/target/loop.c:224!
   nvme_loop_init_hctx+0x7d/0x80
   __blk_mq_realloc_hw_ctxs+0x3af/0xa80
   nvme_alloc_ns+0x1a2/0x22f0

The check protects nothing. ctrl->queues has nr_io_queues + 1 entries
for the life of the controller, the tag set never has more hardware
queues than that, and nvme_loop_queue_rq() rejects requests until the
controller is live again.

Remove it.

Fixes: 3a85a5de29 ("nvme-loop: add a NVMe loopback host driver")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Keith Busch <kbusch@kernel.org>
This commit is contained in:
Josef Bacik 2026-10-28 10:42:23 -06:00 committed by Keith Busch
parent 3f98ce65a8
commit 64e21d7820
1 changed files with 0 additions and 2 deletions
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2
drivers/nvme/target/loop.c
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@ -221,8 +221,6 @@ static int nvme_loop_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
struct nvme_loop_ctrl *ctrl = to_loop_ctrl(data);
struct nvme_loop_queue *queue = &ctrl->queues[hctx_idx + 1];
BUG_ON(hctx_idx >= ctrl->ctrl.queue_count);
/*
* flush_end_io() can be called recursively for us, so use our own
* lock class key for avoiding lockdep possible recursive locking,