From: Logan Gunthorpe <logang@deltatee.com>
To: 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>,
"John Hubbard" <jhubbard@nvidia.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>,
"Logan Gunthorpe" <logang@deltatee.com>
Subject: [PATCH v2 15/22] dma-direct: Support PCI P2PDMA pages in dma-direct map_sg
Date: Thu, 13 May 2021 16:31:56 -0600 [thread overview]
Message-ID: <20210513223203.5542-16-logang@deltatee.com> (raw)
In-Reply-To: <20210513223203.5542-1-logang@deltatee.com>
Add PCI P2PDMA support for dma_direct_map_sg() so that it can map
PCI P2PDMA pages directly without a hack in the callers. This allows
for heterogeneous SGLs that contain both P2PDMA and regular pages.
A P2PDMA page may have three possible outcomes when being mapped:
1) If the data path between the two devices doesn't go through the
root port, then it should be mapped with a PCI bus address
2) If the data path goes through the host bridge, it should be mapped
normally, as though it were a CPU physical address
3) It is not possible for the two devices to communicate and thus
the mapping operation should fail (and it will return -EREMOTEIO).
SGL segments that contain PCI bus addresses are marked with
sg_dma_mark_pci_p2pdma() and are ignored when unmapped.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
kernel/dma/direct.c | 44 ++++++++++++++++++++++++++++++++++++++------
1 file changed, 38 insertions(+), 6 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 803ee9321170..567dac942e89 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -13,6 +13,7 @@
#include <linux/vmalloc.h>
#include <linux/set_memory.h>
#include <linux/slab.h>
+#include <linux/pci-p2pdma.h>
#include "direct.h"
/*
@@ -381,29 +382,60 @@ void dma_direct_sync_sg_for_cpu(struct device *dev,
arch_sync_dma_for_cpu_all();
}
+/*
+ * Unmaps segments, except for ones marked as pci_p2pdma which do not
+ * require any further action as they contain a bus address.
+ */
void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
struct scatterlist *sg;
int i;
- for_each_sg(sgl, sg, nents, i)
- dma_direct_unmap_page(dev, sg->dma_address, sg_dma_len(sg), dir,
- attrs);
+ for_each_sg(sgl, sg, nents, i) {
+ if (sg_is_dma_pci_p2pdma(sg)) {
+ sg_dma_unmark_pci_p2pdma(sg);
+ } else {
+ dma_direct_unmap_page(dev, sg->dma_address,
+ sg_dma_len(sg), dir, attrs);
+ }
+ }
}
#endif
int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
enum dma_data_direction dir, unsigned long attrs)
{
- int i;
+ struct pci_p2pdma_map_state p2pdma_state = {};
+ enum pci_p2pdma_map_type map;
struct scatterlist *sg;
+ int i, ret;
for_each_sg(sgl, sg, nents, i) {
+ if (is_pci_p2pdma_page(sg_page(sg))) {
+ map = pci_p2pdma_map_segment(&p2pdma_state, dev, sg);
+ switch (map) {
+ case PCI_P2PDMA_MAP_BUS_ADDR:
+ continue;
+ case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE:
+ /*
+ * Mapping through host bridge should be
+ * mapped normally, thus we do nothing
+ * and continue below.
+ */
+ break;
+ default:
+ ret = -EREMOTEIO;
+ goto out_unmap;
+ }
+ }
+
sg->dma_address = dma_direct_map_page(dev, sg_page(sg),
sg->offset, sg->length, dir, attrs);
- if (sg->dma_address == DMA_MAPPING_ERROR)
+ if (sg->dma_address == DMA_MAPPING_ERROR) {
+ ret = -EINVAL;
goto out_unmap;
+ }
sg_dma_len(sg) = sg->length;
}
@@ -411,7 +443,7 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
out_unmap:
dma_direct_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
- return -EINVAL;
+ return ret;
}
dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
--
2.20.1
next prev parent reply other threads:[~2021-05-13 22:32 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-13 22:31 [PATCH v2 00/22] Add new DMA mapping operation for P2PDMA Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 01/22] PCI/P2PDMA: Rename upstream_bridge_distance() and rework documentation Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 02/22] PCI/P2PDMA: Use a buffer on the stack for collecting the acs list Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 03/22] PCI/P2PDMA: Cleanup type for return value of calc_map_type_and_dist() Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 04/22] PCI/P2PDMA: Avoid pci_get_slot() which sleeps Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 05/22] PCI/P2PDMA: Print a warning if the host bridge is not in the whitelist Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 06/22] PCI/P2PDMA: Attempt to set map_type if it has not been set Logan Gunthorpe
2021-05-14 13:49 ` Christoph Hellwig
2021-05-14 16:15 ` Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 07/22] PCI/P2PDMA: Refactor pci_p2pdma_map_type() to take pagemap and device Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 08/22] dma-mapping: Allow map_sg() ops to return negative error codes Logan Gunthorpe
2021-05-14 13:51 ` Christoph Hellwig
2021-05-14 16:15 ` Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 09/22] dma-direct: Return appropriate error code from dma_direct_map_sg() Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 10/22] iommu: Return full error code from iommu_map_sg[_atomic]() Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 11/22] dma-iommu: Return error code from iommu_dma_map_sg() Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 12/22] lib/scatterlist: Add flag for indicating P2PDMA segments in an SGL Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 13/22] PCI/P2PDMA: Make pci_p2pdma_map_type() non-static Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 14/22] PCI/P2PDMA: Introduce helpers for dma_map_sg implementations Logan Gunthorpe
2021-05-14 13:53 ` Christoph Hellwig
2021-05-14 16:16 ` Logan Gunthorpe
2021-05-13 22:31 ` Logan Gunthorpe [this message]
2021-05-14 13:57 ` [PATCH v2 15/22] dma-direct: Support PCI P2PDMA pages in dma-direct map_sg Christoph Hellwig
2021-05-14 16:17 ` Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 16/22] dma-mapping: Add flags to dma_map_ops to indicate PCI P2PDMA support Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 17/22] iommu/dma: Support PCI P2PDMA pages in dma-iommu map_sg Logan Gunthorpe
2021-05-13 22:31 ` [PATCH v2 18/22] nvme-pci: Check DMA ops when indicating support for PCI P2PDMA Logan Gunthorpe
2021-05-13 22:32 ` [PATCH v2 19/22] nvme-pci: Convert to using dma_map_sgtable() Logan Gunthorpe
2021-05-13 22:32 ` [PATCH v2 20/22] RDMA/core: Introduce ib_dma_pci_p2p_dma_supported() Logan Gunthorpe
2021-05-13 22:32 ` [PATCH v2 21/22] RDMA/rw: use dma_map_sgtable() Logan Gunthorpe
2021-05-13 22:32 ` [PATCH v2 22/22] PCI/P2PDMA: Remove pci_p2pdma_[un]map_sg() Logan Gunthorpe
2021-05-14 14:00 ` [PATCH v2 00/22] Add new DMA mapping operation for P2PDMA Christoph Hellwig
2021-05-14 16:30 ` Logan Gunthorpe
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