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From: Logan Gunthorpe <logang@deltatee.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	"James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Jens Axboe <axboe@kernel.dk>,
	Steve Wise <swise@opengridcomputing.com>,
	Stephen Bates <sbates@raithlin.com>,
	Max Gurtovoy <maxg@mellanox.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Keith Busch <keith.busch@intel.com>,
	Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
	linux-pci@vger.kernel.org, linux-scsi@vger.kernel.org,
	linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org,
	linux-nvdimm@ml01.01.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 5/8] scatterlist: Modify SG copy functions to support io memory.
Date: Fri, 31 Mar 2017 09:41:56 -0600	[thread overview]
Message-ID: <435d4471-436b-87e6-8827-c9fc6cbdde2c@deltatee.com> (raw)
In-Reply-To: <20170331070950.GA9059@infradead.org>



On 31/03/17 01:09 AM, Christoph Hellwig wrote:
> You're calling memcpy_{to,from}_iomem on non-__iomem pointers.  This
> is a fundamental no-go as we keep I/O memory separate from kernel
> pointers.

Yes, that's true, however I don't know how we could get around that when
the iomem is referenced by struct pages inside a scatter gather list. Do
we need to now have special __iomem sgls? And even still, I'm not sure
how that could work when the nvme target code is using the same sgls to
sometimes point to iomem and sometimes point to regular memory.

I'm certainly open to suggestions, though.

Logan

  reply	other threads:[~2017-03-31 15:42 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-30 22:12 [RFC 0/8] Copy Offload with Peer-to-Peer PCI Memory Logan Gunthorpe
2017-03-30 22:12 ` [RFC 1/8] Introduce Peer-to-Peer memory (p2pmem) device Logan Gunthorpe
2017-03-31 18:49   ` Sinan Kaya
2017-03-31 21:23     ` Logan Gunthorpe
2017-03-31 21:38       ` Sinan Kaya
2017-03-31 22:42         ` Logan Gunthorpe
2017-03-31 23:51           ` Sinan Kaya
2017-04-01  1:57             ` Logan Gunthorpe
2017-04-01  2:17               ` okaya
2017-04-01 22:16                 ` Logan Gunthorpe
2017-04-02  2:26                   ` Sinan Kaya
2017-04-02 17:21                     ` Logan Gunthorpe
2017-04-02 21:03                       ` Sinan Kaya
2017-04-03  4:26                         ` Logan Gunthorpe
2017-04-25 11:58                           ` Marta Rybczynska
2017-04-25 16:58                             ` Logan Gunthorpe
2017-03-30 22:12 ` [RFC 2/8] cxgb4: setup pcie memory window 4 and create p2pmem region Logan Gunthorpe
2017-04-04 10:42   ` Sagi Grimberg
2017-04-04 15:56     ` Logan Gunthorpe
2017-04-05 15:41     ` Steve Wise
2017-03-30 22:12 ` [RFC 3/8] nvmet: Use p2pmem in nvme target Logan Gunthorpe
2017-04-04 10:40   ` Sagi Grimberg
2017-04-04 16:16     ` Logan Gunthorpe
2017-04-06  5:47       ` Sagi Grimberg
2017-04-06 15:52         ` Logan Gunthorpe
2017-03-30 22:12 ` [RFC 4/8] p2pmem: Add debugfs "stats" file Logan Gunthorpe
2017-04-04 10:46   ` Sagi Grimberg
2017-04-04 17:25     ` Logan Gunthorpe
2017-04-05 15:43     ` Steve Wise
2017-03-30 22:12 ` [RFC 5/8] scatterlist: Modify SG copy functions to support io memory Logan Gunthorpe
2017-03-31  7:09   ` Christoph Hellwig
2017-03-31 15:41     ` Logan Gunthorpe [this message]
2017-04-03 21:20       ` Logan Gunthorpe
2017-04-03 21:44         ` Dan Williams
2017-04-03 22:10           ` Logan Gunthorpe
2017-04-03 22:47             ` Dan Williams
2017-04-03 23:12               ` Logan Gunthorpe
2017-04-04  0:07                 ` Dan Williams
2017-04-07 17:59                   ` Logan Gunthorpe
2017-03-30 22:12 ` [RFC 6/8] nvmet: Be careful about using iomem accesses when dealing with p2pmem Logan Gunthorpe
2017-04-04 10:59   ` Sagi Grimberg
2017-04-04 15:46     ` Jason Gunthorpe
2017-04-04 17:21       ` Logan Gunthorpe
2017-04-06  5:33       ` Sagi Grimberg
2017-04-06 16:02         ` Logan Gunthorpe
2017-04-06 16:35         ` Jason Gunthorpe
2017-04-07 11:19         ` Stephen  Bates
2017-04-10  8:29           ` Sagi Grimberg
2017-04-10 16:03             ` Logan Gunthorpe
2017-03-30 22:12 ` [RFC 7/8] p2pmem: Support device removal Logan Gunthorpe
2017-03-30 22:12 ` [RFC 8/8] p2pmem: Added char device user interface Logan Gunthorpe
2017-04-12  5:22 ` [RFC 0/8] Copy Offload with Peer-to-Peer PCI Memory Benjamin Herrenschmidt
2017-04-12 17:09   ` Logan Gunthorpe
2017-04-12 21:55     ` Benjamin Herrenschmidt
2017-04-13 21:22       ` Logan Gunthorpe
2017-04-13 22:37         ` Benjamin Herrenschmidt
2017-04-13 23:26         ` Bjorn Helgaas
2017-04-14  4:16           ` Jason Gunthorpe
2017-04-14  4:40             ` Logan Gunthorpe
2017-04-14 11:37               ` Benjamin Herrenschmidt
2017-04-14 11:39                 ` Benjamin Herrenschmidt
2017-04-14 11:37             ` Benjamin Herrenschmidt
2017-04-14 17:30               ` Logan Gunthorpe
2017-04-14 19:04                 ` Bjorn Helgaas
2017-04-14 22:07                   ` Benjamin Herrenschmidt
2017-04-15 17:41                     ` Logan Gunthorpe
2017-04-15 22:09                       ` Dan Williams
2017-04-16  3:01                         ` Benjamin Herrenschmidt
2017-04-16  4:46                           ` Logan Gunthorpe
2017-04-16 15:53                           ` Dan Williams
2017-04-16 16:34                             ` Logan Gunthorpe
2017-04-16 22:31                               ` Benjamin Herrenschmidt
2017-04-24  7:36                                 ` Knut Omang
2017-04-24 16:14                                   ` Logan Gunthorpe
2017-04-25  6:30                                     ` Knut Omang
2017-04-25 17:03                                       ` Logan Gunthorpe
2017-04-25 21:23                                         ` Stephen  Bates
2017-04-25 21:23                                   ` Stephen  Bates
2017-04-16 22:26                             ` Benjamin Herrenschmidt
2017-04-15 22:17                       ` Benjamin Herrenschmidt
2017-04-16  5:36                         ` Logan Gunthorpe

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