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Commit 013b559a authored by Javier González's avatar Javier González Committed by Greg Kroah-Hartman
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lightnvm: pblk: fix race condition on metadata I/O 



[ Upstream commit d8adaa3b86324c6186d0adf74bc256bdacfffdb6 ]

In pblk, when a new line is allocated, metadata for the previously
written line is scheduled. This is done through a fixed memory region
that is shared through time and contexts across different lines and
therefore protected by a lock. Unfortunately, this lock is not properly
covering all the metadata used for sharing this memory regions,
resulting in a race condition.

This patch fixes this race condition by protecting this metadata
properly.

Fixes: dd2a4343 ("lightnvm: pblk: sched. metadata on write thread")
Signed-off-by: default avatarJavier González <javier@cnexlabs.com>
Signed-off-by: default avatarMatias Bjørling <mb@lightnvm.io>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3c5b1d33

drivers/lightnvm/pblk-write.c

+7 −7
Original line number Diff line number Diff line
@@ -417,12 +417,11 @@ int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line) 
			rqd->ppa_list[i] = addr_to_gen_ppa(pblk, paddr, id);

	}



	emeta->mem += rq_len;

	if (emeta->mem >= lm->emeta_len[0]) {

	spin_lock(&l_mg->close_lock);

	emeta->mem += rq_len;

	if (emeta->mem >= lm->emeta_len[0])

		list_del(&meta_line->list);

	spin_unlock(&l_mg->close_lock);

	}



	pblk_down_page(pblk, rqd->ppa_list, rqd->nr_ppas);
@@ -491,14 +490,15 @@ static struct pblk_line *pblk_should_submit_meta_io(struct pblk *pblk, 
	struct pblk_line *meta_line;



	spin_lock(&l_mg->close_lock);

retry:

	if (list_empty(&l_mg->emeta_list)) {

		spin_unlock(&l_mg->close_lock);

		return NULL;

	}

	meta_line = list_first_entry(&l_mg->emeta_list, struct pblk_line, list);

	if (meta_line->emeta->mem >= lm->emeta_len[0])

		goto retry;

	if (meta_line->emeta->mem >= lm->emeta_len[0]) {

		spin_unlock(&l_mg->close_lock);

		return NULL;

	}

	spin_unlock(&l_mg->close_lock);



	if (!pblk_valid_meta_ppa(pblk, meta_line, data_rqd))