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
Cc: "Christoph Hellwig" <hch@lst.de>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"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>,
"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>,
"Stephen Bates" <sbates@raithlin.com>,
"Logan Gunthorpe" <logang@deltatee.com>
Subject: [PATCH v10 1/8] mm: introduce FOLL_PCI_P2PDMA to gate getting PCI P2PDMA pages
Date: Thu, 22 Sep 2022 10:39:19 -0600 [thread overview]
Message-ID: <20220922163926.7077-2-logang@deltatee.com> (raw)
In-Reply-To: <20220922163926.7077-1-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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.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 21f8b27bd9fd..3cea77c8a9ea 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2897,6 +2897,7 @@ 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 5abdaf487460..108848b67f6f 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -601,6 +601,12 @@ static struct page *follow_page_pte(struct vm_area_struct *vma,
goto out;
}
+ if (unlikely(!(flags & FOLL_PCI_P2PDMA) &&
+ is_pci_p2pdma_page(page))) {
+ page = ERR_PTR(-EREMOTEIO);
+ goto out;
+ }
+
VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) &&
!PageAnonExclusive(page), page);
@@ -1039,6 +1045,9 @@ 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;
@@ -2383,6 +2392,10 @@ 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(!(flags & FOLL_PCI_P2PDMA) &&
+ is_pci_p2pdma_page(page)))
+ goto pte_unmap;
+
folio = try_grab_folio(page, 1, flags);
if (!folio)
goto pte_unmap;
@@ -2462,6 +2475,12 @@ 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))) {
@@ -2950,7 +2969,8 @@ 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:[~2022-09-22 16:39 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-22 16:39 [PATCH v10 0/8] Userspace P2PDMA with O_DIRECT NVMe devices Logan Gunthorpe
2022-09-22 16:39 ` Logan Gunthorpe [this message]
2022-09-23 18:13 ` [PATCH v10 1/8] mm: introduce FOLL_PCI_P2PDMA to gate getting PCI P2PDMA pages Jason Gunthorpe
2022-09-23 19:08 ` Logan Gunthorpe
2022-09-23 19:53 ` Jason Gunthorpe
2022-09-23 20:11 ` Logan Gunthorpe
2022-09-23 22:58 ` Jason Gunthorpe
2022-09-23 23:01 ` Logan Gunthorpe
2022-09-23 23:07 ` Jason Gunthorpe
2022-09-23 23:14 ` Logan Gunthorpe
2022-09-23 23:21 ` Jason Gunthorpe
2022-09-23 23:35 ` Logan Gunthorpe
2022-09-23 23:51 ` Logan Gunthorpe
2022-09-26 22:57 ` Jason Gunthorpe
2022-09-28 21:38 ` Logan Gunthorpe
2022-09-22 16:39 ` [PATCH v10 2/8] iov_iter: introduce iov_iter_get_pages_[alloc_]flags() Logan Gunthorpe
2022-09-22 16:39 ` [PATCH v10 3/8] block: add check when merging zone device pages Logan Gunthorpe
2022-09-22 16:39 ` [PATCH v10 4/8] lib/scatterlist: " Logan Gunthorpe
2022-09-22 16:39 ` [PATCH v10 5/8] block: set FOLL_PCI_P2PDMA in __bio_iov_iter_get_pages() Logan Gunthorpe
2022-09-22 16:39 ` [PATCH v10 6/8] block: set FOLL_PCI_P2PDMA in bio_map_user_iov() Logan Gunthorpe
2022-09-22 16:39 ` [PATCH v10 7/8] PCI/P2PDMA: Allow userspace VMA allocations through sysfs Logan Gunthorpe
2022-09-22 18:27 ` Bjorn Helgaas
2022-09-23 8:15 ` Greg Kroah-Hartman
2022-09-22 16:39 ` [PATCH v10 8/8] ABI: sysfs-bus-pci: add documentation for p2pmem allocate Logan Gunthorpe
2022-09-23 8:15 ` Greg Kroah-Hartman
2022-09-23 6:01 ` [PATCH v10 0/8] Userspace P2PDMA with O_DIRECT NVMe devices Christoph Hellwig
2022-09-23 15:25 ` Logan Gunthorpe
2022-09-23 8:16 ` Greg Kroah-Hartman
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