From: Jason Gunthorpe <jgg@ziepe.ca>
To: Jerome Glisse <jglisse@redhat.com>,
Ralph Campbell <rcampbell@nvidia.com>,
Felix.Kuehling@amd.com
Cc: linux-mm@kvack.org, John Hubbard <jhubbard@nvidia.com>,
dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org,
Christoph Hellwig <hch@lst.de>, Philip Yang <Philip.Yang@amd.com>,
Jason Gunthorpe <jgg@mellanox.com>
Subject: [PATCH v2 hmm 7/9] mm/hmm: do not unconditionally set pfns when returning EBUSY
Date: Mon, 23 Mar 2020 22:14:55 -0300 [thread overview]
Message-ID: <20200324011457.2817-8-jgg@ziepe.ca> (raw)
In-Reply-To: <20200324011457.2817-1-jgg@ziepe.ca>
From: Jason Gunthorpe <jgg@mellanox.com>
In hmm_vma_handle_pte() and hmm_vma_walk_hugetlb_entry() if fault happens
then -EBUSY will be returned and the pfns input flags will have been
destroyed.
For hmm_vma_handle_pte() set HMM_PFN_NONE only on the success returns that
don't otherwise store to pfns.
For hmm_vma_walk_hugetlb_entry() all exit paths already set pfns, so
remove the redundant store.
Fixes: 2aee09d8c116 ("mm/hmm: change hmm_vma_fault() to allow write fault on page basis")
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
---
mm/hmm.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/mm/hmm.c b/mm/hmm.c
index e114110ad498a2..bf77b852f12d3a 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -249,11 +249,11 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
pte_t pte = *ptep;
uint64_t orig_pfn = *pfn;
- *pfn = range->values[HMM_PFN_NONE];
if (pte_none(pte)) {
required_fault = hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0);
if (required_fault)
goto fault;
+ *pfn = range->values[HMM_PFN_NONE];
return 0;
}
@@ -274,8 +274,10 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
}
required_fault = hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0);
- if (!required_fault)
+ if (!required_fault) {
+ *pfn = range->values[HMM_PFN_NONE];
return 0;
+ }
if (!non_swap_entry(entry))
goto fault;
@@ -493,7 +495,6 @@ static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask,
i = (start - range->start) >> PAGE_SHIFT;
orig_pfn = range->pfns[i];
- range->pfns[i] = range->values[HMM_PFN_NONE];
cpu_flags = pte_to_hmm_pfn_flags(range, entry);
required_fault = hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags);
if (required_fault) {
--
2.25.2
next prev parent reply other threads:[~2020-03-24 1:15 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-24 1:14 [PATCH v2 hmm 0/9] Small hmm_range_fault() cleanups Jason Gunthorpe
2020-03-24 1:14 ` [PATCH v2 hmm 1/9] mm/hmm: remove pgmap checking for devmap pages Jason Gunthorpe
2020-03-24 1:14 ` [PATCH v2 hmm 2/9] mm/hmm: return the fault type from hmm_pte_need_fault() Jason Gunthorpe
2020-03-24 7:27 ` Christoph Hellwig
2020-03-24 18:58 ` Jason Gunthorpe
2020-03-24 1:14 ` [PATCH v2 hmm 3/9] mm/hmm: remove unused code and tidy comments Jason Gunthorpe
2020-03-24 7:27 ` Christoph Hellwig
2020-03-24 1:14 ` [PATCH v2 hmm 4/9] mm/hmm: remove HMM_FAULT_SNAPSHOT Jason Gunthorpe
2020-03-24 7:33 ` Christoph Hellwig
2020-03-24 19:31 ` Jason Gunthorpe
2020-03-24 1:14 ` [PATCH v2 hmm 5/9] mm/hmm: remove the CONFIG_TRANSPARENT_HUGEPAGE #ifdef Jason Gunthorpe
2020-03-24 7:33 ` Christoph Hellwig
2020-03-24 1:14 ` [PATCH v2 hmm 6/9] mm/hmm: use device_private_entry_to_pfn() Jason Gunthorpe
2020-03-24 7:34 ` Christoph Hellwig
2020-03-24 1:14 ` Jason Gunthorpe [this message]
2020-03-24 7:37 ` [PATCH v2 hmm 7/9] mm/hmm: do not unconditionally set pfns when returning EBUSY Christoph Hellwig
2020-03-24 15:47 ` Jason Gunthorpe
2020-03-24 1:14 ` [PATCH v2 hmm 8/9] mm/hmm: do not set pfns when returning an error code Jason Gunthorpe
2020-03-24 7:38 ` Christoph Hellwig
2020-03-24 1:14 ` [PATCH v2 hmm 9/9] mm/hmm: return error for non-vma snapshots Jason Gunthorpe
2020-03-24 7:45 ` Christoph Hellwig
2020-03-26 21:21 ` [PATCH v2 hmm 0/9] Small hmm_range_fault() cleanups Ralph Campbell
2020-03-27 20:00 [PATCH v3 " Jason Gunthorpe
2020-03-27 20:00 ` [PATCH v2 hmm 7/9] mm/hmm: do not unconditionally set pfns when returning EBUSY Jason Gunthorpe
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