From: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
To: linux-nvme@lists.infradead.org
Subject: [PATCH v2 1/1] nvme-pci: Hold cq_poll_lock while completing CQEs
Date: Wed, 26 Feb 2020 18:53:43 -0800 [thread overview]
Message-ID: <1582772023-67704-1-git-send-email-bijan.mottahedeh@oracle.com> (raw)
Avoid scheduling a polling thread if it has cqe's to complete, otherwise
another thread may free enough tags out of order, allowing a queue wrap.
This is an interim solution. Longer term, the two-pass completion should
be fixed. It was done that way when submit and complete processing were
using the same spinlock, so reducing the critical section was helpful,
but that's not needed anymore.
Fixes: dabcefab45d3 ("nvme: provide optimized poll function for separate poll queues")
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
---
drivers/nvme/host/pci.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index ace4dd9..d3f23d6 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1078,9 +1078,9 @@ static int nvme_poll(struct blk_mq_hw_ctx *hctx)
spin_lock(&nvmeq->cq_poll_lock);
found = nvme_process_cq(nvmeq, &start, &end, -1);
+ nvme_complete_cqes(nvmeq, start, end);
spin_unlock(&nvmeq->cq_poll_lock);
- nvme_complete_cqes(nvmeq, start, end);
return found;
}
--
1.8.3.1
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next reply other threads:[~2020-02-27 2:54 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-27 2:53 Bijan Mottahedeh [this message]
2020-02-27 16:35 ` [PATCH v2 1/1] nvme-pci: Hold cq_poll_lock while completing CQEs Keith Busch
2020-02-29 18:57 ` Christoph Hellwig
2020-03-02 19:04 ` Bijan Mottahedeh
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