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    SubjectRe: [PATCH] lightnvm: pblk: fix race condition on metadata I/O
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    On 08/17/2018 12:22 PM, Javier González wrote:
    > 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 on a race condition.
    >
    > This patch fixes this race condition by protecting this metadata
    > properly.
    >
    > Fixes: dd2a43437337 ("lightnvm: pblk: sched. metadata on write thread")
    >
    > Signed-off-by: Javier González <javier@cnexlabs.com>
    > ---
    > drivers/lightnvm/pblk-write.c | 14 +++++++-------
    > 1 file changed, 7 insertions(+), 7 deletions(-)
    >
    > diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
    > index 508c63701eda..df99c45778d4 100644
    > --- a/drivers/lightnvm/pblk-write.c
    > +++ b/drivers/lightnvm/pblk-write.c
    > @@ -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);
    > }
    >
    > + spin_lock(&l_mg->close_lock);
    > emeta->mem += rq_len;
    > - if (emeta->mem >= lm->emeta_len[0]) {
    > - spin_lock(&l_mg->close_lock);
    > + if (emeta->mem >= lm->emeta_len[0])
    > list_del(&meta_line->list);
    > - spin_unlock(&l_mg->close_lock);
    > - }
    > + 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))
    >

    Thanks. Applied for 4.20.

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