From: Jérôme Glisse <jglisse@xxxxxxxxxx> Subject: mm/hmm: cleanup special vma handling (VM_SPECIAL) 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@xxxxxxxxxx Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx> Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx> Cc: Evgeny Baskakov <ebaskakov@xxxxxxxxxx> Cc: Ralph Campbell <rcampbell@xxxxxxxxxx> Cc: Mark Hairgrove <mhairgrove@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/hmm.c | 40 ++++++++++++++++++++-------------------- 1 file changed, 20 insertions(+), 20 deletions(-) diff -puN mm/hmm.c~mm-hmm-cleanup-special-vma-handling-vm_special mm/hmm.c --- a/mm/hmm.c~mm-hmm-cleanup-special-vma-handling-vm_special +++ a/mm/hmm.c @@ -324,14 +324,6 @@ static int hmm_vma_do_fault(struct mm_wa 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 *r 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 *r 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 *rang 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 *rang 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; _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
