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>,
"Martin Oliveira" <martin.oliveira@eideticom.com>,
"Chaitanya Kulkarni" <ckulkarnilinux@gmail.com>,
"Ralph Campbell" <rcampbell@nvidia.com>,
"Logan Gunthorpe" <logang@deltatee.com>
Subject: [PATCH v6 14/21] mm: introduce FOLL_PCI_P2PDMA to gate getting PCI P2PDMA pages
Date: Thu, 7 Apr 2022 09:47:10 -0600 [thread overview]
Message-ID: <20220407154717.7695-15-logang@deltatee.com> (raw)
In-Reply-To: <20220407154717.7695-1-logang@deltatee.com>
GUP Callers that expect PCI P2PDMA pages can now set FOLL_PCI_P2PDMA to
allow obtaining P2PDMA pages. If GUP is called without the flag and a
P2PDMA page is found, it will return an error.
FOLL_PCI_P2PDMA cannot be set if FOLL_LONGTERM is set.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
include/linux/mm.h | 1 +
mm/gup.c | 22 +++++++++++++++++++++-
2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e34edb775334..14ef41af8b77 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2936,6 +2936,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
#define FOLL_SPLIT_PMD 0x20000 /* split huge pmd before returning */
#define FOLL_PIN 0x40000 /* pages must be released via unpin_user_page */
#define FOLL_FAST_ONLY 0x80000 /* gup_fast: prevent fall-back to slow gup */
+#define FOLL_PCI_P2PDMA 0x100000 /* allow returning PCI P2PDMA pages */
/*
* FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each
diff --git a/mm/gup.c b/mm/gup.c
index f598a037eb04..0af6f802ca38 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -490,6 +490,12 @@ static struct page *follow_page_pte(struct vm_area_struct *vma,
page = pte_page(pte);
else
goto no_page;
+
+ if (unlikely(!(flags & FOLL_PCI_P2PDMA) &&
+ is_pci_p2pdma_page(page))) {
+ page = ERR_PTR(-EREMOTEIO);
+ goto out;
+ }
} else if (unlikely(!page)) {
if (flags & FOLL_DUMP) {
/* Avoid special (like zero) pages in core dumps */
@@ -919,6 +925,9 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
if ((gup_flags & FOLL_LONGTERM) && vma_is_fsdax(vma))
return -EOPNOTSUPP;
+ if ((gup_flags & FOLL_LONGTERM) && (gup_flags & FOLL_PCI_P2PDMA))
+ return -EOPNOTSUPP;
+
if (vma_is_secretmem(vma))
return -EFAULT;
@@ -2184,6 +2193,10 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
page = pte_page(pte);
+ if (unlikely(pte_devmap(pte) && !(flags & FOLL_PCI_P2PDMA) &&
+ is_pci_p2pdma_page(page)))
+ goto pte_unmap;
+
folio = try_grab_folio(page, 1, flags);
if (!folio)
goto pte_unmap;
@@ -2258,6 +2271,12 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr,
undo_dev_pagemap(nr, nr_start, flags, pages);
break;
}
+
+ if (!(flags & FOLL_PCI_P2PDMA) && is_pci_p2pdma_page(page)) {
+ undo_dev_pagemap(nr, nr_start, flags, pages);
+ break;
+ }
+
SetPageReferenced(page);
pages[*nr] = page;
if (unlikely(!try_grab_page(page, flags))) {
@@ -2729,7 +2748,8 @@ static int internal_get_user_pages_fast(unsigned long start,
if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM |
FOLL_FORCE | FOLL_PIN | FOLL_GET |
- FOLL_FAST_ONLY | FOLL_NOFAULT)))
+ FOLL_FAST_ONLY | FOLL_NOFAULT |
+ FOLL_PCI_P2PDMA)))
return -EINVAL;
if (gup_flags & FOLL_PIN)
--
2.30.2
next prev parent reply other threads:[~2022-04-07 17:28 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-07 15:46 [PATCH v6 00/21] Userspace P2PDMA with O_DIRECT NVMe devices Logan Gunthorpe
2022-04-07 15:46 ` [PATCH v6 01/21] lib/scatterlist: add flag for indicating P2PDMA segments in an SGL Logan Gunthorpe
2022-04-07 15:46 ` [PATCH v6 02/21] PCI/P2PDMA: Attempt to set map_type if it has not been set Logan Gunthorpe
2022-04-07 15:46 ` [PATCH v6 03/21] PCI/P2PDMA: Expose pci_p2pdma_map_type() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 04/21] PCI/P2PDMA: Introduce helpers for dma_map_sg implementations Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 05/21] dma-mapping: allow EREMOTEIO return code for P2PDMA transfers Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 06/21] dma-direct: support PCI P2PDMA pages in dma-direct map_sg Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 07/21] dma-mapping: add flags to dma_map_ops to indicate PCI P2PDMA support Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 08/21] iommu/dma: support PCI P2PDMA pages in dma-iommu map_sg Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 09/21] nvme-pci: check DMA ops when indicating support for PCI P2PDMA Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 10/21] nvme-pci: convert to using dma_map_sgtable() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 11/21] RDMA/core: introduce ib_dma_pci_p2p_dma_supported() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 12/21] RDMA/rw: drop pci_p2pdma_[un]map_sg() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 13/21] PCI/P2PDMA: Remove pci_p2pdma_[un]map_sg() Logan Gunthorpe
2022-04-07 15:47 ` Logan Gunthorpe [this message]
2022-04-07 15:47 ` [PATCH v6 15/21] iov_iter: introduce iov_iter_get_pages_[alloc_]flags() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 16/21] block: add check when merging zone device pages Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 17/21] lib/scatterlist: " Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 18/21] block: set FOLL_PCI_P2PDMA in __bio_iov_iter_get_pages() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 19/21] block: set FOLL_PCI_P2PDMA in bio_map_user_iov() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 20/21] PCI/P2PDMA: Introduce pci_mmap_p2pmem() Logan Gunthorpe
2022-05-27 12:55 ` Jason Gunthorpe
2022-05-27 15:35 ` Logan Gunthorpe
2022-05-27 19:03 ` Jason Gunthorpe
2022-05-27 22:41 ` Logan Gunthorpe
2022-06-02 0:00 ` Jason Gunthorpe
2022-06-02 16:16 ` Logan Gunthorpe
2022-06-02 16:30 ` Jason Gunthorpe
2022-06-02 16:45 ` Logan Gunthorpe
2022-06-02 17:18 ` Jason Gunthorpe
2022-06-02 16:49 ` Logan Gunthorpe
2022-06-02 17:28 ` Jason Gunthorpe
2022-06-02 17:49 ` Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 21/21] nvme-pci: allow mmaping the CMB in userspace Logan Gunthorpe
2022-05-16 22:31 ` [PATCH v6 00/21] Userspace P2PDMA with O_DIRECT NVMe devices Chaitanya Kulkarni
2022-05-16 22:35 ` Logan Gunthorpe
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