From: axboe@fb.com (Jens Axboe)
Subject: [PATCH v3 RESEND] nvme: avoid cqe corruption when update at the same time as read
Date: Tue, 22 Mar 2016 10:28:07 -0600 [thread overview]
Message-ID: <56F17297.50900@fb.com> (raw)
In-Reply-To: <927773622.9658030.1458658926133.JavaMail.zimbra@kalray.eu>
On 03/22/2016 09:02 AM, Marta Rybczynska wrote:
> Make sure the CQE phase (validity) is read before the rest of the
> structure. The phase bit is the highest address and the CQE
> read will happen on most platforms from lower to upper addresses
> and will be done by multiple non-atomic loads. If the structure
> is updated by PCI during the reads from the processor, the
> processor may get a corrupted copy.
>
> The addition of the new nvme_cqe_valid function that verifies
> the validity bit also allows refactoring of the other CQE read
> sequences.
Added for this merge window, thanks.
--
Jens Axboe
prev parent reply other threads:[~2016-03-22 16:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-22 15:02 [PATCH v3 RESEND] nvme: avoid cqe corruption when update at the same time as read Marta Rybczynska
2016-03-22 15:04 ` Marta Rybczynska
2016-03-22 15:06 ` Keith Busch
2016-03-22 16:28 ` Jens Axboe [this message]
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