From 855ce7d2525c97cf706ad82a419f0c2d632b9481 Mon Sep 17 00:00:00 2001 From: Jérôme Glisse Date: Tue, 10 Apr 2018 16:28:42 -0700 Subject: mm/hmm: cleanup special vma handling (VM_SPECIAL) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Special vma (one with any of the VM_SPECIAL flags) can not be access by device because there is no consistent model across device drivers on those vma and their backing memory. This patch directly use hmm_range struct for hmm_pfns_special() argument as it is always affecting the whole vma and thus the whole range. It also make behavior consistent after this patch both hmm_vma_fault() and hmm_vma_get_pfns() returns -EINVAL when facing such vma. Previously hmm_vma_fault() returned 0 and hmm_vma_get_pfns() return -EINVAL but both were filling the HMM pfn array with special entry. Link: http://lkml.kernel.org/r/20180323005527.758-10-jglisse@redhat.com Signed-off-by: Jérôme Glisse Reviewed-by: John Hubbard Cc: Evgeny Baskakov Cc: Ralph Campbell Cc: Mark Hairgrove Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hmm.c | 40 ++++++++++++++++++++-------------------- 1 file changed, 20 insertions(+), 20 deletions(-) (limited to 'mm/hmm.c') diff --git a/mm/hmm.c b/mm/hmm.c index b69f30fc064b..a93c1e35df91 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -324,14 +324,6 @@ static int hmm_vma_do_fault(struct mm_walk *walk, return -EAGAIN; } -static void hmm_pfns_special(uint64_t *pfns, - unsigned long addr, - unsigned long end) -{ - for (; addr < end; addr += PAGE_SIZE, pfns++) - *pfns = HMM_PFN_SPECIAL; -} - static int hmm_pfns_bad(unsigned long addr, unsigned long end, struct mm_walk *walk) @@ -529,6 +521,14 @@ fault: return 0; } +static void hmm_pfns_special(struct hmm_range *range) +{ + unsigned long addr = range->start, i = 0; + + for (; addr < range->end; addr += PAGE_SIZE, i++) + range->pfns[i] = HMM_PFN_SPECIAL; +} + /* * hmm_vma_get_pfns() - snapshot CPU page table for a range of virtual addresses * @range: range being snapshotted @@ -553,12 +553,6 @@ int hmm_vma_get_pfns(struct hmm_range *range) struct mm_walk mm_walk; struct hmm *hmm; - /* FIXME support hugetlb fs */ - if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) { - hmm_pfns_special(range->pfns, range->start, range->end); - return -EINVAL; - } - /* Sanity check, this really should not happen ! */ if (range->start < vma->vm_start || range->start >= vma->vm_end) return -EINVAL; @@ -572,6 +566,12 @@ int hmm_vma_get_pfns(struct hmm_range *range) if (!hmm->mmu_notifier.ops) return -EINVAL; + /* FIXME support hugetlb fs */ + if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) { + hmm_pfns_special(range); + return -EINVAL; + } + if (!(vma->vm_flags & VM_READ)) { /* * If vma do not allow read access, then assume that it does @@ -740,6 +740,12 @@ int hmm_vma_fault(struct hmm_range *range, bool write, bool block) if (!hmm->mmu_notifier.ops) return -EINVAL; + /* FIXME support hugetlb fs */ + if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) { + hmm_pfns_special(range); + return -EINVAL; + } + if (!(vma->vm_flags & VM_READ)) { /* * If vma do not allow read access, then assume that it does @@ -751,12 +757,6 @@ int hmm_vma_fault(struct hmm_range *range, bool write, bool block) return -EPERM; } - /* FIXME support hugetlb fs */ - if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) { - hmm_pfns_special(range->pfns, range->start, range->end); - return 0; - } - /* Initialize range to track CPU page table update */ spin_lock(&hmm->lock); range->valid = true; -- cgit