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From: Logan Gunthorpe <logang@deltatee.com>
To: Christoph Hellwig <hch@lst.de>
Cc: dri-devel@lists.freedesktop.org, dm-devel@redhat.com,
	target-devel@vger.kernel.org,
	Sumit Semwal <sumit.semwal@linaro.org>,
	devel@driverdev.osuosl.org,
	"James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
	linux-scsi@vger.kernel.org, linux-nvdimm@lists.01.org,
	linux-rdma@vger.kernel.org, open-iscsi@googlegroups.com,
	linux-media@vger.kernel.org, intel-gfx@lists.freedesktop.org,
	sparmaintainer@unisys.com, linux-raid@vger.kernel.org,
	megaraidlinux.pdl@broadcom.com, Jens Axboe <axboe@kernel.dk>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	netdev@vger.kernel.org, Matthew Wilcox <mawilcox@microsoft.com>,
	linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-crypto@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v2 01/21] scatterlist: Introduce sg_map helper functions
Date: Thu, 27 Apr 2017 09:44:18 -0600	[thread overview]
Message-ID: <3b7f3aba-d609-dca7-149f-107757d63fb0@deltatee.com> (raw)
In-Reply-To: <20170427065338.GA20677@lst.de>



On 27/04/17 12:53 AM, Christoph Hellwig wrote:
> I think you'll need to follow the existing kmap semantics and never
> fail the iomem version either.  Otherwise you'll have a special case
> that's almost never used that has a different error path.
>
> Again, wrong way.  Suddenly making things fail for your special case
> that normally don't fail is a receipe for bugs.

I don't disagree but these restrictions make the problem impossible to
solve? If there is iomem behind a page in an SGL and someone tries to
map it, we either have to fail or we break iomem safety which was your
original concern.

Logan

_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

WARNING: multiple messages have this Message-ID (diff)
From: Logan Gunthorpe <logang@deltatee.com>
To: Christoph Hellwig <hch@lst.de>
Cc: dri-devel@lists.freedesktop.org,
	Stephen Bates <sbates@raithlin.com>,
	dm-devel@redhat.com, target-devel@vger.kernel.org,
	Sumit Semwal <sumit.semwal@linaro.org>,
	devel@driverdev.osuosl.org,
	"James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
	linux-scsi@vger.kernel.org, linux-nvdimm@lists.01.org,
	linux-rdma@vger.kernel.org,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	open-iscsi@googlegroups.com, linux-media@vger.kernel.org,
	intel-gfx@lists.freedesktop.org, sparmaintainer@unisys.com,
	linux-raid@vger.kernel.org,
	Dan Williams <dan.j.williams@intel.com>,
	megaraidlinux.pdl@broadcom.com, Jens Axboe <axboe@kernel.dk>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	netdev@vger.kernel.org, Matthew Wilcox <mawilcox@microsoft.com>,
	linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-crypto@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v2 01/21] scatterlist: Introduce sg_map helper functions
Date: Thu, 27 Apr 2017 09:44:18 -0600	[thread overview]
Message-ID: <3b7f3aba-d609-dca7-149f-107757d63fb0@deltatee.com> (raw)
In-Reply-To: <20170427065338.GA20677@lst.de>



On 27/04/17 12:53 AM, Christoph Hellwig wrote:
> I think you'll need to follow the existing kmap semantics and never
> fail the iomem version either.  Otherwise you'll have a special case
> that's almost never used that has a different error path.
>
> Again, wrong way.  Suddenly making things fail for your special case
> that normally don't fail is a receipe for bugs.

I don't disagree but these restrictions make the problem impossible to
solve? If there is iomem behind a page in an SGL and someone tries to
map it, we either have to fail or we break iomem safety which was your
original concern.

Logan

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

WARNING: multiple messages have this Message-ID (diff)
From: Logan Gunthorpe <logang@deltatee.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
	linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
	intel-gfx@lists.freedesktop.org, linux-raid@vger.kernel.org,
	linux-mmc@vger.kernel.org, linux-nvdimm@ml01.01.org,
	linux-scsi@vger.kernel.org, open-iscsi@googlegroups.com,
	megaraidlinux.pdl@broadcom.com, sparmaintainer@unisys.com,
	devel@driverdev.osuosl.org, target-devel@vger.kernel.org,
	netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
	dm-devel@redhat.com,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	"James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
	Jens Axboe <axboe@kernel.dk>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	Matthew Wilcox <mawilcox@microsoft.com>,
	Sumit Semwal <sumit.semwal@linaro.org>,
	Stephen Bates <sbates@raithlin.com>
Subject: Re: [PATCH v2 01/21] scatterlist: Introduce sg_map helper functions
Date: Thu, 27 Apr 2017 09:44:18 -0600	[thread overview]
Message-ID: <3b7f3aba-d609-dca7-149f-107757d63fb0@deltatee.com> (raw)
In-Reply-To: <20170427065338.GA20677@lst.de>



On 27/04/17 12:53 AM, Christoph Hellwig wrote:
> I think you'll need to follow the existing kmap semantics and never
> fail the iomem version either.  Otherwise you'll have a special case
> that's almost never used that has a different error path.
>
> Again, wrong way.  Suddenly making things fail for your special case
> that normally don't fail is a receipe for bugs.

I don't disagree but these restrictions make the problem impossible to
solve? If there is iomem behind a page in an SGL and someone tries to
map it, we either have to fail or we break iomem safety which was your
original concern.

Logan

WARNING: multiple messages have this Message-ID (diff)
From: Logan Gunthorpe <logang@deltatee.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
	linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
	intel-gfx@lists.freedesktop.org, linux-raid@vger.kernel.org,
	linux-mmc@vger.kernel.org, linux-nvdimm@lists.01.org,
	linux-scsi@vger.kernel.org, open-iscsi@googlegroups.com,
	megaraidlinux.pdl@broadcom.com, sparmaintainer@unisys.com,
	devel@driverdev.osuosl.org, target-devel@vger.kernel.org,
	netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
	dm-devel@redhat.com,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	"James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
	Jens Axboe <axboe@kernel.dk>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	Matthew Wilcox <mawilcox@microsoft.com>,
	Sumit Semwal <sumit.semwal@linaro.org>,
	Stephen Bates <sbates@raithlin.com>
Subject: Re: [PATCH v2 01/21] scatterlist: Introduce sg_map helper functions
Date: Thu, 27 Apr 2017 09:44:18 -0600	[thread overview]
Message-ID: <3b7f3aba-d609-dca7-149f-107757d63fb0@deltatee.com> (raw)
In-Reply-To: <20170427065338.GA20677@lst.de>



On 27/04/17 12:53 AM, Christoph Hellwig wrote:
> I think you'll need to follow the existing kmap semantics and never
> fail the iomem version either.  Otherwise you'll have a special case
> that's almost never used that has a different error path.
>
> Again, wrong way.  Suddenly making things fail for your special case
> that normally don't fail is a receipe for bugs.

I don't disagree but these restrictions make the problem impossible to
solve? If there is iomem behind a page in an SGL and someone tries to
map it, we either have to fail or we break iomem safety which was your
original concern.

Logan

  parent reply	other threads:[~2017-04-27 15:44 UTC|newest]

Thread overview: 183+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-25 18:20 [PATCH v2 00/21] Introduce common scatterlist map function Logan Gunthorpe
2017-04-25 18:20 ` Logan Gunthorpe
2017-04-25 18:20 ` Logan Gunthorpe
2017-04-25 18:20 ` Logan Gunthorpe
2017-04-25 18:20 ` [PATCH v2 01/21] scatterlist: Introduce sg_map helper functions Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-26  7:44   ` Christoph Hellwig
2017-04-26  7:44     ` Christoph Hellwig
2017-04-26  7:44     ` Christoph Hellwig
2017-04-26  7:44     ` Christoph Hellwig
2017-04-26  7:44     ` Christoph Hellwig
2017-04-26 18:11     ` Logan Gunthorpe
2017-04-26 18:11       ` Logan Gunthorpe
2017-04-26 18:11       ` Logan Gunthorpe
2017-04-26 18:11       ` Logan Gunthorpe
2017-04-27  6:53       ` Christoph Hellwig
2017-04-27  6:53         ` Christoph Hellwig
2017-04-27  6:53         ` Christoph Hellwig
2017-04-27  6:53         ` Christoph Hellwig
2017-04-27  6:53         ` Christoph Hellwig
     [not found]         ` <20170427065338.GA20677-jcswGhMUV9g@public.gmane.org>
2017-04-27 15:27           ` Jason Gunthorpe
2017-04-27 15:27             ` Jason Gunthorpe
     [not found]             ` <20170427152720.GA7662-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-04-27 15:57               ` Logan Gunthorpe
2017-04-27 15:57                 ` Logan Gunthorpe
2017-04-27 15:44         ` Logan Gunthorpe [this message]
2017-04-27 15:44           ` Logan Gunthorpe
2017-04-27 15:44           ` Logan Gunthorpe
2017-04-27 15:44           ` Logan Gunthorpe
2017-04-27 20:13     ` Logan Gunthorpe
2017-04-27 20:13       ` Logan Gunthorpe
2017-04-27 20:13       ` Logan Gunthorpe
2017-04-27 20:13       ` Logan Gunthorpe
2017-04-26  8:59   ` Christian König
2017-04-26  8:59     ` Christian König
2017-04-26  8:59     ` Christian König
2017-04-26  8:59     ` Christian König
2017-04-26  8:59     ` Christian König
2017-04-26 23:30     ` Logan Gunthorpe
2017-04-26 23:30       ` Logan Gunthorpe
2017-04-26 23:30       ` Logan Gunthorpe
2017-04-26 23:30       ` Logan Gunthorpe
2017-04-25 18:20 ` [PATCH v2 02/21] libiscsi: Add an internal error code Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-26  7:48   ` Christoph Hellwig
2017-04-26  7:48     ` Christoph Hellwig
2017-04-26  7:48     ` Christoph Hellwig
2017-04-26  7:48     ` Christoph Hellwig
2017-04-26  7:48     ` Christoph Hellwig
2017-04-25 18:20 ` [PATCH v2 03/21] libiscsi: Make use of new the sg_map helper function Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20 ` [PATCH v2 04/21] target: Make use of the new sg_map function at 16 call sites Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20 ` [PATCH v2 05/21] drm/i915: Make use of the new sg_map helper function Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20 ` [PATCH v2 06/21] crypto: hifn_795x: " Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20 ` [PATCH v2 07/21] crypto: shash, caam: " Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-27  3:56   ` Herbert Xu
2017-04-27  3:56     ` Herbert Xu
2017-04-27  3:56     ` Herbert Xu
2017-04-27  3:56     ` Herbert Xu
2017-04-27  3:56     ` Herbert Xu
2017-04-27 15:45     ` Logan Gunthorpe
2017-04-27 15:45       ` Logan Gunthorpe
2017-04-27 15:45       ` Logan Gunthorpe
2017-04-27 15:45       ` Logan Gunthorpe
2017-04-28  6:30       ` Herbert Xu
2017-04-28  6:30         ` Herbert Xu
2017-04-28  6:30         ` Herbert Xu
2017-04-28  6:30         ` Herbert Xu
2017-04-28 16:53         ` Logan Gunthorpe
2017-04-28 16:53           ` Logan Gunthorpe
2017-04-28 16:53           ` Logan Gunthorpe
2017-04-28 16:53           ` Logan Gunthorpe
2017-04-28 17:51           ` Herbert Xu
2017-04-28 17:51             ` Herbert Xu
2017-04-28 17:51             ` Herbert Xu
2017-04-28 17:51             ` Herbert Xu
2017-04-28 19:01             ` Logan Gunthorpe
2017-04-28 19:01               ` Logan Gunthorpe
2017-04-28 19:01               ` Logan Gunthorpe
2017-04-28 19:01               ` Logan Gunthorpe
2017-04-28 19:01               ` Logan Gunthorpe
2017-04-25 18:20 ` [PATCH v2 08/21] dm-crypt: Make use of the new sg_map helper in 4 call sites Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20 ` [PATCH v2 09/21] staging: unisys: visorbus: Make use of the new sg_map helper function Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20 ` [PATCH v2 10/21] RDS: " Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20 ` [PATCH v2 11/21] scsi: ipr, pmcraid, isci: Make use of the new sg_map helper Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20 ` [PATCH v2 12/21] scsi: hisi_sas, mvsas, gdth: Make use of the new sg_map helper function Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:20   ` Logan Gunthorpe
2017-04-25 18:21 ` [PATCH v2 13/21] scsi: arcmsr, ips, megaraid: " Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21 ` [PATCH v2 14/21] scsi: libfc, csiostor: Change to sg_copy_buffer in two drivers Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21 ` [PATCH v2 15/21] xen-blkfront: Make use of the new sg_map helper function Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-26  7:37   ` Roger Pau Monné
2017-04-26  7:37     ` Roger Pau Monné
2017-04-26  7:37     ` Roger Pau Monné
2017-04-26  7:37     ` Roger Pau Monné
2017-04-26  7:37     ` Roger Pau Monné
2017-04-27 20:19     ` Logan Gunthorpe
2017-04-27 20:19       ` Logan Gunthorpe
2017-04-27 20:19       ` Logan Gunthorpe
2017-04-27 20:19       ` Logan Gunthorpe
2017-04-27 20:19       ` Logan Gunthorpe
     [not found]       ` <df6586e2-7d45-6b0b-facb-4dea882df06e-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>
2017-04-27 20:53         ` Jason Gunthorpe
2017-04-27 20:53           ` Jason Gunthorpe
2017-04-27 20:53           ` Jason Gunthorpe
     [not found]           ` <20170427205339.GB26330-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-04-27 21:53             ` Logan Gunthorpe
2017-04-27 21:53               ` Logan Gunthorpe
2017-04-27 21:53               ` Logan Gunthorpe
     [not found]               ` <02ba3c7b-5fab-a06c-fbbf-c3be1c0fae1b-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>
2017-04-27 22:11                 ` Jason Gunthorpe
2017-04-27 22:11                   ` Jason Gunthorpe
2017-04-27 22:11                   ` Jason Gunthorpe
     [not found]                   ` <20170427221132.GA30036-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-04-27 23:03                     ` Logan Gunthorpe
2017-04-27 23:03                       ` Logan Gunthorpe
2017-04-27 23:03                       ` Logan Gunthorpe
     [not found]                       ` <3a7c0d27-0744-4e91-b37f-3885c50455e8-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>
2017-04-27 23:20                         ` Jason Gunthorpe
2017-04-27 23:20                           ` Jason Gunthorpe
2017-04-27 23:20                           ` Jason Gunthorpe
2017-04-27 23:29                           ` Logan Gunthorpe
2017-04-27 23:29                             ` Logan Gunthorpe
2017-04-27 23:29                             ` Logan Gunthorpe
2017-04-25 18:21 ` [PATCH v2 16/21] mmc: sdhci: " Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21 ` [PATCH v2 17/21] mmc: spi: " Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21 ` [PATCH v2 18/21] mmc: tmio: " Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21 ` [PATCH v2 19/21] mmc: sdricoh_cs: " Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21 ` [PATCH v2 20/21] mmc: tifm_sd: " Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21 ` [PATCH v2 21/21] memstick: " Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:21   ` Logan Gunthorpe
2017-04-25 18:40 ` ✓ Fi.CI.BAT: success for Introduce common scatterlist map function (rev2) Patchwork

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