From: hch@lst.de (Christoph Hellwig)
Subject: [PATCH 2/3] nvme: Pass pointers, not dma addresses, to nvme_get/set_features()
Date: Tue, 30 Aug 2016 08:36:51 +0200 [thread overview]
Message-ID: <20160830063651.GA32323@lst.de> (raw)
In-Reply-To: <CALCETrWzfovS+kh=UsJZxNvN-_eypav+Df+NppPHt8FPPOSipw@mail.gmail.com>
On Mon, Aug 29, 2016@04:20:43PM -0700, Andy Lutomirski wrote:
> The "Set Features" command (section 5.15) Figure 103 says:
>
> If using PRPs, this field shall not be a pointer to a PRP List as the
> data buffer may not cross more than one page boundary. If no data
> structure is used as part of the specified feature, then this field is
> not used.
>
> Does the Linux driver use PRPs?
The Linux PCIe driver always uses PRPs - and for admin command only
Fabrics can use SGLs anyway.
> Do we need to worry about kmalloc
> returning a buffer that spans a 4k boundary but does not span a Linux
> page boundary?
Isn't kmalloc supposed to return naturally aligned buffers?
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Keith Busch <keith.busch@intel.com>,
Andy Lutomirski <luto@kernel.org>, Jens Axboe <axboe@fb.com>,
linux-nvme@lists.infradead.org, Christoph Hellwig <hch@lst.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/3] nvme: Pass pointers, not dma addresses, to nvme_get/set_features()
Date: Tue, 30 Aug 2016 08:36:51 +0200 [thread overview]
Message-ID: <20160830063651.GA32323@lst.de> (raw)
In-Reply-To: <CALCETrWzfovS+kh=UsJZxNvN-_eypav+Df+NppPHt8FPPOSipw@mail.gmail.com>
On Mon, Aug 29, 2016 at 04:20:43PM -0700, Andy Lutomirski wrote:
> The "Set Features" command (section 5.15) Figure 103 says:
>
> If using PRPs, this field shall not be a pointer to a PRP List as the
> data buffer may not cross more than one page boundary. If no data
> structure is used as part of the specified feature, then this field is
> not used.
>
> Does the Linux driver use PRPs?
The Linux PCIe driver always uses PRPs - and for admin command only
Fabrics can use SGLs anyway.
> Do we need to worry about kmalloc
> returning a buffer that spans a 4k boundary but does not span a Linux
> page boundary?
Isn't kmalloc supposed to return naturally aligned buffers?
next prev parent reply other threads:[~2016-08-30 6:36 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-29 9:25 [PATCH 0/3] nvme power saving Andy Lutomirski
2016-08-29 9:25 ` Andy Lutomirski
2016-08-29 9:25 ` [PATCH 1/3] nvme/scsi: Remove power management support Andy Lutomirski
2016-08-29 9:25 ` Andy Lutomirski
2016-08-29 9:25 ` [PATCH 2/3] nvme: Pass pointers, not dma addresses, to nvme_get/set_features() Andy Lutomirski
2016-08-29 9:25 ` Andy Lutomirski
2016-08-29 16:27 ` Keith Busch
2016-08-29 16:27 ` Keith Busch
2016-08-29 23:20 ` Andy Lutomirski
2016-08-29 23:20 ` Andy Lutomirski
2016-08-30 6:36 ` Christoph Hellwig [this message]
2016-08-30 6:36 ` Christoph Hellwig
2016-08-30 16:00 ` Andy Lutomirski
2016-08-30 16:00 ` Andy Lutomirski
2016-08-29 9:25 ` [PATCH 3/3] nvme: Enable autonomous power state transitions Andy Lutomirski
2016-08-29 9:25 ` Andy Lutomirski
2016-08-29 15:07 ` J Freyensee
2016-08-29 15:07 ` J Freyensee
2016-08-29 23:16 ` Andy Lutomirski
2016-08-29 23:16 ` Andy Lutomirski
2016-08-30 20:21 ` Andy Lutomirski
2016-08-30 20:21 ` Andy Lutomirski
2016-09-02 18:11 ` J Freyensee
2016-09-02 18:11 ` J Freyensee
2016-09-02 18:50 ` Andy Lutomirski
2016-09-02 18:50 ` Andy Lutomirski
2016-08-29 16:45 ` Keith Busch
2016-08-29 16:45 ` Keith Busch
2016-08-29 23:16 ` Andy Lutomirski
2016-08-29 23:16 ` Andy Lutomirski
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