From: Christoph Hellwig <hch@lst.de>
To: Logan Gunthorpe <logang@deltatee.com>
Cc: "Robin Murphy" <robin.murphy@arm.com>,
linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
linux-block@vger.kernel.org, linux-pci@vger.kernel.org,
linux-mm@kvack.org, iommu@lists.linux-foundation.org,
"Minturn Dave B" <dave.b.minturn@intel.com>,
"John Hubbard" <jhubbard@nvidia.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Matthew Wilcox" <willy@infradead.org>,
"Christian König" <christian.koenig@amd.com>,
"Jason Gunthorpe" <jgg@ziepe.ca>,
"Jason Ekstrand" <jason@jlekstrand.net>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Dan Williams" <dan.j.williams@intel.com>,
"Stephen Bates" <sbates@raithlin.com>,
"Jakowski Andrzej" <andrzej.jakowski@intel.com>,
"Christoph Hellwig" <hch@lst.de>,
"Xiong Jianxin" <jianxin.xiong@intel.com>
Subject: Re: [RFC PATCH v2 06/11] dma-direct: Support PCI P2PDMA pages in dma-direct map_sg
Date: Tue, 16 Mar 2021 08:58:21 +0100 [thread overview]
Message-ID: <20210316075821.GB15949@lst.de> (raw)
In-Reply-To: <367fa81e-588d-5734-c69c-8cdc800dcb7e@deltatee.com>
On Fri, Mar 12, 2021 at 11:27:46AM -0700, Logan Gunthorpe wrote:
> So then we reject the patches that make that change. Seems like an odd
> argument to say that we can't do something that won't cause problems
> because someone might use it as an example and do something that will
> cause problems. Reject the change that causes the problem.
No, the problem is a mess of calling conventions. A calling convention
returning 0 for error, positive values for success is fine. One returning
a negative errno for error and positive values for success is fine a well.
One returning 0 for the usual errors and negativ errnos for an unusual
corner case is just a complete mess.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Logan Gunthorpe <logang@deltatee.com>
Cc: "Robin Murphy" <robin.murphy@arm.com>,
linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
linux-block@vger.kernel.org, linux-pci@vger.kernel.org,
linux-mm@kvack.org, iommu@lists.linux-foundation.org,
"Minturn Dave B" <dave.b.minturn@intel.com>,
"John Hubbard" <jhubbard@nvidia.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Matthew Wilcox" <willy@infradead.org>,
"Christian König" <christian.koenig@amd.com>,
"Jason Gunthorpe" <jgg@ziepe.ca>,
"Jason Ekstrand" <jason@jlekstrand.net>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Dan Williams" <dan.j.williams@intel.com>,
"Stephen Bates" <sbates@raithlin.com>,
"Jakowski Andrzej" <andrzej.jakowski@intel.com>,
"Christoph Hellwig" <hch@lst.de>,
"Xiong Jianxin" <jianxin.xiong@intel.com>
Subject: Re: [RFC PATCH v2 06/11] dma-direct: Support PCI P2PDMA pages in dma-direct map_sg
Date: Tue, 16 Mar 2021 08:58:21 +0100 [thread overview]
Message-ID: <20210316075821.GB15949@lst.de> (raw)
In-Reply-To: <367fa81e-588d-5734-c69c-8cdc800dcb7e@deltatee.com>
On Fri, Mar 12, 2021 at 11:27:46AM -0700, Logan Gunthorpe wrote:
> So then we reject the patches that make that change. Seems like an odd
> argument to say that we can't do something that won't cause problems
> because someone might use it as an example and do something that will
> cause problems. Reject the change that causes the problem.
No, the problem is a mess of calling conventions. A calling convention
returning 0 for error, positive values for success is fine. One returning
a negative errno for error and positive values for success is fine a well.
One returning 0 for the usual errors and negativ errnos for an unusual
corner case is just a complete mess.
_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Logan Gunthorpe <logang@deltatee.com>
Cc: "Minturn Dave B" <dave.b.minturn@intel.com>,
"Jason Gunthorpe" <jgg@ziepe.ca>,
"Jakowski Andrzej" <andrzej.jakowski@intel.com>,
linux-pci@vger.kernel.org,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
"Stephen Bates" <sbates@raithlin.com>,
linux-block@vger.kernel.org, linux-mm@kvack.org,
iommu@lists.linux-foundation.org,
"Christoph Hellwig" <hch@lst.de>,
"Matthew Wilcox" <willy@infradead.org>,
"Jason Ekstrand" <jason@jlekstrand.net>,
"John Hubbard" <jhubbard@nvidia.com>,
"Dan Williams" <dan.j.williams@intel.com>,
"Robin Murphy" <robin.murphy@arm.com>,
"Christian König" <christian.koenig@amd.com>,
"Xiong Jianxin" <jianxin.xiong@intel.com>
Subject: Re: [RFC PATCH v2 06/11] dma-direct: Support PCI P2PDMA pages in dma-direct map_sg
Date: Tue, 16 Mar 2021 08:58:21 +0100 [thread overview]
Message-ID: <20210316075821.GB15949@lst.de> (raw)
In-Reply-To: <367fa81e-588d-5734-c69c-8cdc800dcb7e@deltatee.com>
On Fri, Mar 12, 2021 at 11:27:46AM -0700, Logan Gunthorpe wrote:
> So then we reject the patches that make that change. Seems like an odd
> argument to say that we can't do something that won't cause problems
> because someone might use it as an example and do something that will
> cause problems. Reject the change that causes the problem.
No, the problem is a mess of calling conventions. A calling convention
returning 0 for error, positive values for success is fine. One returning
a negative errno for error and positive values for success is fine a well.
One returning 0 for the usual errors and negativ errnos for an unusual
corner case is just a complete mess.
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2021-03-16 7:59 UTC|newest]
Thread overview: 141+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-11 23:31 [RFC PATCH v2 00/11] Add support to dma_map_sg for P2PDMA Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 01/11] PCI/P2PDMA: Pass gfp_mask flags to upstream_bridge_distance_warn() Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-12 20:39 ` Bjorn Helgaas
2021-03-12 20:39 ` Bjorn Helgaas
2021-03-12 20:39 ` Bjorn Helgaas
2021-03-12 20:53 ` Logan Gunthorpe
2021-03-12 20:53 ` Logan Gunthorpe
2021-03-12 20:53 ` Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 02/11] PCI/P2PDMA: Avoid pci_get_slot() which sleeps Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-12 20:57 ` Bjorn Helgaas
2021-03-12 20:57 ` Bjorn Helgaas
2021-03-12 20:57 ` Bjorn Helgaas
2021-03-12 21:37 ` Logan Gunthorpe
2021-03-12 21:37 ` Logan Gunthorpe
2021-03-12 21:37 ` Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 03/11] PCI/P2PDMA: Attempt to set map_type if it has not been set Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 04/11] PCI/P2PDMA: Introduce pci_p2pdma_should_map_bus() and pci_p2pdma_bus_offset() Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-13 1:38 ` Ira Weiny
2021-03-13 1:38 ` Ira Weiny
2021-03-13 1:38 ` Ira Weiny
2021-03-15 16:27 ` Logan Gunthorpe
2021-03-15 16:27 ` Logan Gunthorpe
2021-03-15 16:27 ` Logan Gunthorpe
2021-03-24 17:21 ` Jason Gunthorpe
2021-03-24 17:21 ` Jason Gunthorpe
2021-03-24 17:21 ` Jason Gunthorpe
2021-03-24 18:34 ` Christian König
2021-03-24 18:34 ` Christian König
2021-03-24 18:34 ` Christian König
2021-03-13 2:32 ` Ira Weiny
2021-03-13 2:32 ` Ira Weiny
2021-03-13 2:32 ` Ira Weiny
2021-03-15 16:30 ` Logan Gunthorpe
2021-03-15 16:30 ` Logan Gunthorpe
2021-03-15 16:30 ` Logan Gunthorpe
2021-03-16 8:14 ` Christoph Hellwig
2021-03-16 8:14 ` Christoph Hellwig
2021-03-16 8:14 ` Christoph Hellwig
2021-03-11 23:31 ` [RFC PATCH v2 05/11] lib/scatterlist: Add flag for indicating P2PDMA segments in an SGL Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 06/11] dma-direct: Support PCI P2PDMA pages in dma-direct map_sg Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-12 15:52 ` Robin Murphy
2021-03-12 15:52 ` Robin Murphy
2021-03-12 15:52 ` Robin Murphy
2021-03-12 16:24 ` Logan Gunthorpe
2021-03-12 16:24 ` Logan Gunthorpe
2021-03-12 16:24 ` Logan Gunthorpe
2021-03-12 18:11 ` Robin Murphy
2021-03-12 18:11 ` Robin Murphy
2021-03-12 18:11 ` Robin Murphy
2021-03-12 18:27 ` Logan Gunthorpe
2021-03-12 18:27 ` Logan Gunthorpe
2021-03-12 18:27 ` Logan Gunthorpe
2021-03-16 7:58 ` Christoph Hellwig [this message]
2021-03-16 7:58 ` Christoph Hellwig
2021-03-16 7:58 ` Christoph Hellwig
2021-03-16 15:54 ` Logan Gunthorpe
2021-03-16 15:54 ` Logan Gunthorpe
2021-03-16 15:54 ` Logan Gunthorpe
2021-03-16 7:56 ` Christoph Hellwig
2021-03-16 7:56 ` Christoph Hellwig
2021-03-16 7:56 ` Christoph Hellwig
2021-03-16 8:11 ` Christoph Hellwig
2021-03-16 8:11 ` Christoph Hellwig
2021-03-16 8:11 ` Christoph Hellwig
2021-03-11 23:31 ` [RFC PATCH v2 07/11] dma-mapping: Add flags to dma_map_ops to indicate PCI P2PDMA support Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-13 2:36 ` Ira Weiny
2021-03-13 2:36 ` Ira Weiny
2021-03-13 2:36 ` Ira Weiny
2021-03-15 16:33 ` Logan Gunthorpe
2021-03-15 16:33 ` Logan Gunthorpe
2021-03-15 16:33 ` Logan Gunthorpe
2021-03-16 8:00 ` Christoph Hellwig
2021-03-16 8:00 ` Christoph Hellwig
2021-03-16 8:00 ` Christoph Hellwig
2021-03-16 8:15 ` Christoph Hellwig
2021-03-16 8:15 ` Christoph Hellwig
2021-03-16 8:15 ` Christoph Hellwig
2021-03-11 23:31 ` [RFC PATCH v2 08/11] iommu/dma: Support PCI P2PDMA pages in dma-iommu map_sg Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-12 15:52 ` Robin Murphy
2021-03-12 15:52 ` Robin Murphy
2021-03-12 15:52 ` Robin Murphy
2021-03-12 17:03 ` Logan Gunthorpe
2021-03-12 17:03 ` Logan Gunthorpe
2021-03-12 17:03 ` Logan Gunthorpe
2021-03-12 19:47 ` Robin Murphy
2021-03-12 19:47 ` Robin Murphy
2021-03-12 19:47 ` Robin Murphy
2021-03-12 20:06 ` Logan Gunthorpe
2021-03-12 20:06 ` Logan Gunthorpe
2021-03-12 20:06 ` Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 09/11] block: Add BLK_STS_P2PDMA Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-16 8:00 ` Christoph Hellwig
2021-03-16 8:00 ` Christoph Hellwig
2021-03-16 8:00 ` Christoph Hellwig
2021-03-16 16:02 ` Logan Gunthorpe
2021-03-16 16:02 ` Logan Gunthorpe
2021-03-16 16:02 ` Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 10/11] nvme-pci: Check DMA ops when indicating support for PCI P2PDMA Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 11/11] nvme-pci: Convert to using dma_map_sg for p2pdma pages Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:31 ` Logan Gunthorpe
2021-03-11 23:59 ` Jason Gunthorpe
2021-03-11 23:59 ` Jason Gunthorpe
2021-03-11 23:59 ` Jason Gunthorpe
2021-03-12 1:37 ` Logan Gunthorpe
2021-03-12 1:37 ` Logan Gunthorpe
2021-03-12 1:37 ` Logan Gunthorpe
2021-03-12 15:51 ` [RFC PATCH v2 00/11] Add support to dma_map_sg for P2PDMA Robin Murphy
2021-03-12 15:51 ` Robin Murphy
2021-03-12 15:51 ` Robin Murphy
2021-03-12 16:18 ` Logan Gunthorpe
2021-03-12 16:18 ` Logan Gunthorpe
2021-03-12 16:18 ` Logan Gunthorpe
2021-03-12 17:46 ` Robin Murphy
2021-03-12 17:46 ` Robin Murphy
2021-03-12 17:46 ` Robin Murphy
2021-03-12 18:24 ` Logan Gunthorpe
2021-03-12 18:24 ` Logan Gunthorpe
2021-03-12 18:24 ` Logan Gunthorpe
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