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From: Christoph Hellwig <hch@lst.de>
To: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Jonathan Derrick <jonathan.derrick@intel.com>,
	Revanth Rajashekar <revanth.rajashekar@intel.com>,
	Jens Axboe <axboe@kernel.dk>, Keith Busch <kbusch@kernel.org>,
	Jens Axboe <axboe@fb.com>, Christoph Hellwig <hch@lst.de>,
	Sagi Grimberg <sagi@grimberg.me>,
	Rafael Antognolli <Rafael.Antognolli@intel.com>,
	Scott Bauer <scott.bauer@intel.com>,
	Serge Semin <fancer.lancer@gmail.com>,
	Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
	Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] block: sed-opal: Cache-line-align the cmd/resp buffers
Date: Sat, 10 Sep 2022 07:32:03 +0200	[thread overview]
Message-ID: <20220910053203.GB23052@lst.de> (raw)
In-Reply-To: <20220909191916.16013-3-Sergey.Semin@baikalelectronics.ru>

On Fri, Sep 09, 2022 at 10:19:16PM +0300, Serge Semin wrote:
> In accordance with [1] the DMA-able memory buffers must be
> cacheline-aligned otherwise the cache writing-back and invalidation
> performed during the mapping may cause the adjacent data being lost. It's
> specifically required for the DMA-noncoherent platforms. Seeing the
> opal_dev.{cmd,resp} buffers are used for DMAs in the NVME and SCSI/SD
> drivers in framework of the nvme_sec_submit() and sd_sec_submit() methods
> respectively we must make sure the passed buffers are cacheline-aligned to
> prevent the denoted problem.

Same comment as for the previous one, this should work, but I think
separate allocations for the DMAable buffers would document the intent
much better.  Given that the opal initialization isn't a fast path
I don't think that the overhead should matter either.

  reply	other threads:[~2022-09-10  5:32 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-09 19:19 [PATCH 0/2] block/nvme: Fix DMA-noncoherent platforms support Serge Semin
2022-09-09 19:19 ` [PATCH 1/2] nvme-hwmon: Cache-line-align the NVME SMART log-buffer Serge Semin
2022-09-09 19:42   ` Keith Busch
2022-09-09 20:53     ` Serge Semin
2022-09-09 20:36   ` Guenter Roeck
2022-09-10  5:30   ` Christoph Hellwig
2022-09-10 12:35     ` Serge Semin
2022-09-10 18:09       ` Serge Semin
2022-09-12  8:29       ` Christoph Hellwig
2022-09-25 22:23         ` Serge Semin
2022-09-26 14:39           ` Christoph Hellwig
2022-09-26 19:04             ` Serge Semin
2022-09-10 14:33     ` Guenter Roeck
2022-09-09 19:19 ` [PATCH 2/2] block: sed-opal: Cache-line-align the cmd/resp buffers Serge Semin
2022-09-10  5:32   ` Christoph Hellwig [this message]
2022-09-11 16:28     ` Serge Semin
2022-09-25 22:30       ` Serge Semin

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