From: John Hubbard <jhubbard@nvidia.com>
To: Logan Gunthorpe <logang@deltatee.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>
Cc: "Stephen Bates" <sbates@raithlin.com>,
"Christoph Hellwig" <hch@lst.de>,
"Dan Williams" <dan.j.williams@intel.com>,
"Jason Gunthorpe" <jgg@ziepe.ca>,
"Christian König" <christian.koenig@amd.com>,
"Don Dutile" <ddutile@redhat.com>,
"Matthew Wilcox" <willy@infradead.org>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Jakowski Andrzej" <andrzej.jakowski@intel.com>,
"Minturn Dave B" <dave.b.minturn@intel.com>,
"Jason Ekstrand" <jason@jlekstrand.net>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Xiong Jianxin" <jianxin.xiong@intel.com>,
"Bjorn Helgaas" <helgaas@kernel.org>,
"Ira Weiny" <ira.weiny@intel.com>,
"Robin Murphy" <robin.murphy@arm.com>
Subject: Re: [PATCH 10/16] dma-mapping: Add flags to dma_map_ops to indicate PCI P2PDMA support
Date: Sun, 2 May 2021 17:32:02 -0700 [thread overview]
Message-ID: <85bd104b-2816-f803-44d4-d5623d4f81af@nvidia.com> (raw)
In-Reply-To: <20210408170123.8788-11-logang@deltatee.com>
On 4/8/21 10:01 AM, Logan Gunthorpe wrote:
> Add a flags member to the dma_map_ops structure with one flag to
> indicate support for PCI P2PDMA.
>
> Also, add a helper to check if a device supports PCI P2PDMA.
>
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> ---
> include/linux/dma-map-ops.h | 3 +++
> include/linux/dma-mapping.h | 5 +++++
> kernel/dma/mapping.c | 18 ++++++++++++++++++
> 3 files changed, 26 insertions(+)
>
> diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
> index 51872e736e7b..481892822104 100644
> --- a/include/linux/dma-map-ops.h
> +++ b/include/linux/dma-map-ops.h
> @@ -12,6 +12,9 @@
> struct cma;
>
> struct dma_map_ops {
> + unsigned int flags;
> +#define DMA_F_PCI_P2PDMA_SUPPORTED (1 << 0)
> +
Can we move this up and out of the struct member area, so that it looks
more like this:
/*
* Values for struct dma_map_ops.flags:
*
* DMA_F_PCI_P2PDMA_SUPPORTED: <documentation here...this is a good place to
* explain exactly what this flag is for.>
*/
#define DMA_F_PCI_P2PDMA_SUPPORTED (1 << 0)
struct dma_map_ops {
unsigned int flags;
> void *(*alloc)(struct device *dev, size_t size,
> dma_addr_t *dma_handle, gfp_t gfp,
> unsigned long attrs);
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index 50b8f586cf59..c31980ecca62 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -146,6 +146,7 @@ int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
> unsigned long attrs);
> bool dma_can_mmap(struct device *dev);
> int dma_supported(struct device *dev, u64 mask);
> +bool dma_pci_p2pdma_supported(struct device *dev);
> int dma_set_mask(struct device *dev, u64 mask);
> int dma_set_coherent_mask(struct device *dev, u64 mask);
> u64 dma_get_required_mask(struct device *dev);
> @@ -247,6 +248,10 @@ static inline int dma_supported(struct device *dev, u64 mask)
> {
> return 0;
> }
> +static inline bool dma_pci_p2pdma_supported(struct device *dev)
> +{
> + return 0;
Should be:
return false;
> +}
> static inline int dma_set_mask(struct device *dev, u64 mask)
> {
> return -EIO;
> diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
> index 923089c4267b..ce44a0fcc4e5 100644
> --- a/kernel/dma/mapping.c
> +++ b/kernel/dma/mapping.c
> @@ -573,6 +573,24 @@ int dma_supported(struct device *dev, u64 mask)
> }
> EXPORT_SYMBOL(dma_supported);
>
> +bool dma_pci_p2pdma_supported(struct device *dev)
> +{
> + const struct dma_map_ops *ops = get_dma_ops(dev);
> +
> + /* if ops is not set, dma direct will be used which supports P2PDMA */
> + if (!ops)
> + return true;
> +
> + /*
> + * Note: dma_ops_bypass is not checked here because P2PDMA should
> + * not be used with dma mapping ops that do not have support even
> + * if the specific device is bypassing them.
> + */
> +
> + return ops->flags & DMA_F_PCI_P2PDMA_SUPPORTED;
Wow, rather unusual combination of things in order decide this. It feels
a bit over-complicated to have flags and ops and a bool function all
dealing with the same 1-bit answer, but there is no caller shown here,
so I'll have to come back to this after reviewing subsequent patches.
thanks,
--
John Hubbard
NVIDIA
> +}
> +EXPORT_SYMBOL_GPL(dma_pci_p2pdma_supported);
> +
> #ifdef CONFIG_ARCH_HAS_DMA_SET_MASK
> void arch_dma_set_mask(struct device *dev, u64 mask);
> #else
>
next prev parent reply other threads:[~2021-05-03 0:32 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 17:01 [PATCH 00/16] Add new DMA mapping operation for P2PDMA Logan Gunthorpe
2021-04-08 17:01 ` [PATCH 01/16] PCI/P2PDMA: Pass gfp_mask flags to upstream_bridge_distance_warn() Logan Gunthorpe
2021-05-02 3:58 ` John Hubbard
2021-05-03 15:57 ` Logan Gunthorpe
2021-05-03 18:17 ` John Hubbard
2021-05-03 18:20 ` Logan Gunthorpe
2021-05-03 18:23 ` John Hubbard
2021-05-03 18:24 ` Christoph Hellwig
2021-05-11 16:05 ` Don Dutile
2021-05-11 16:12 ` Logan Gunthorpe
2021-05-11 16:23 ` Don Dutile
2021-04-08 17:01 ` [PATCH 02/16] PCI/P2PDMA: Avoid pci_get_slot() which sleeps Logan Gunthorpe
2021-05-02 5:35 ` John Hubbard
2021-05-03 16:08 ` Logan Gunthorpe
2021-05-03 18:20 ` John Hubbard
2021-05-03 18:25 ` Christoph Hellwig
2021-05-11 16:05 ` Don Dutile
2021-05-11 16:16 ` Logan Gunthorpe
2021-05-11 16:05 ` Don Dutile
2021-05-11 16:14 ` Logan Gunthorpe
2021-04-08 17:01 ` [PATCH 03/16] PCI/P2PDMA: Attempt to set map_type if it has not been set Logan Gunthorpe
2021-05-02 19:58 ` John Hubbard
2021-05-03 16:17 ` Logan Gunthorpe
2021-05-03 18:22 ` John Hubbard
2021-05-03 18:35 ` Christoph Hellwig
2021-05-03 18:46 ` Logan Gunthorpe
2021-05-11 16:05 ` Don Dutile
2021-04-08 17:01 ` [PATCH 04/16] PCI/P2PDMA: Refactor pci_p2pdma_map_type() to take pagmap and device Logan Gunthorpe
2021-05-02 20:41 ` John Hubbard
2021-05-03 16:30 ` Logan Gunthorpe
2021-05-03 18:31 ` John Hubbard
2021-05-03 18:56 ` Logan Gunthorpe
2021-05-03 21:54 ` John Hubbard
2021-05-03 22:57 ` Jason Gunthorpe
2021-05-03 23:40 ` John Hubbard
2021-04-08 17:01 ` [PATCH 05/16] dma-mapping: Introduce dma_map_sg_p2pdma() Logan Gunthorpe
2021-04-27 19:22 ` Jason Gunthorpe
2021-04-27 22:49 ` Logan Gunthorpe
2021-04-27 19:31 ` Jason Gunthorpe
2021-04-27 22:55 ` Logan Gunthorpe
2021-04-27 23:01 ` Jason Gunthorpe
2021-05-03 18:28 ` Christoph Hellwig
2021-05-03 18:31 ` Logan Gunthorpe
2021-05-02 21:23 ` John Hubbard
2021-05-03 16:38 ` Logan Gunthorpe
2021-05-11 16:05 ` Don Dutile
2021-04-08 17:01 ` [PATCH 06/16] lib/scatterlist: Add flag for indicating P2PDMA segments in an SGL Logan Gunthorpe
2021-05-02 22:34 ` John Hubbard
2021-04-08 17:01 ` [PATCH 07/16] PCI/P2PDMA: Make pci_p2pdma_map_type() non-static Logan Gunthorpe
2021-05-02 22:44 ` John Hubbard
2021-05-03 16:39 ` Logan Gunthorpe
2021-05-11 16:06 ` Don Dutile
2021-05-11 16:17 ` Logan Gunthorpe
2021-04-08 17:01 ` [PATCH 08/16] PCI/P2PDMA: Introduce helpers for dma_map_sg implementations Logan Gunthorpe
2021-05-02 22:52 ` John Hubbard
2021-05-03 0:50 ` John Hubbard
2021-05-03 17:15 ` Logan Gunthorpe
2021-04-08 17:01 ` [PATCH 09/16] dma-direct: Support PCI P2PDMA pages in dma-direct map_sg Logan Gunthorpe
2021-04-27 19:33 ` Jason Gunthorpe
2021-04-27 19:40 ` Jason Gunthorpe
2021-04-27 22:56 ` Logan Gunthorpe
2021-05-02 23:28 ` John Hubbard
2021-05-02 23:32 ` John Hubbard
2021-05-03 17:06 ` Logan Gunthorpe
2021-05-03 16:55 ` Logan Gunthorpe
2021-05-04 0:12 ` John Hubbard
2021-05-03 17:04 ` Logan Gunthorpe
2021-05-04 0:01 ` John Hubbard
2021-04-08 17:01 ` [PATCH 10/16] dma-mapping: Add flags to dma_map_ops to indicate PCI P2PDMA support Logan Gunthorpe
2021-05-03 0:32 ` John Hubbard [this message]
2021-05-03 17:09 ` Logan Gunthorpe
2021-05-11 16:06 ` Don Dutile
2021-05-11 16:19 ` Logan Gunthorpe
2021-04-08 17:01 ` [PATCH 11/16] iommu/dma: Support PCI P2PDMA pages in dma-iommu map_sg Logan Gunthorpe
2021-04-27 19:43 ` Jason Gunthorpe
2021-04-27 22:59 ` Logan Gunthorpe
2021-05-03 1:14 ` John Hubbard
2021-05-06 23:59 ` Logan Gunthorpe
2021-05-11 16:06 ` Don Dutile
2021-05-11 16:35 ` Logan Gunthorpe
2021-04-08 17:01 ` [PATCH 12/16] nvme-pci: Check DMA ops when indicating support for PCI P2PDMA Logan Gunthorpe
2021-05-03 1:29 ` John Hubbard
2021-05-03 17:17 ` Logan Gunthorpe
2021-05-04 0:17 ` John Hubbard
2021-04-08 17:01 ` [PATCH 13/16] nvme-pci: Convert to using dma_map_sg_p2pdma for p2pdma pages Logan Gunthorpe
2021-05-03 1:34 ` John Hubbard
2021-05-03 17:19 ` Logan Gunthorpe
2021-05-04 0:26 ` John Hubbard
2021-04-08 17:01 ` [PATCH 14/16] nvme-rdma: Ensure dma support when using p2pdma Logan Gunthorpe
2021-04-27 19:47 ` Jason Gunthorpe
2021-04-27 22:59 ` Logan Gunthorpe
2021-05-03 1:37 ` John Hubbard
2021-04-08 17:01 ` [PATCH 15/16] RDMA/rw: use dma_map_sg_p2pdma() Logan Gunthorpe
2021-04-08 17:01 ` [PATCH 16/16] PCI/P2PDMA: Remove pci_p2pdma_[un]map_sg() Logan Gunthorpe
2021-04-27 19:28 ` [PATCH 00/16] Add new DMA mapping operation for P2PDMA Jason Gunthorpe
2021-04-27 20:21 ` John Hubbard
2021-04-27 20:48 ` Dan Williams
2021-05-02 1:22 ` John Hubbard
2021-05-11 16:05 ` Don Dutile
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