From: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Subject: userfaultfd: shmem: use shmem_mcopy_atomic_pte for shared memory The shmem_mcopy_atomic_pte implements low lever part of UFFDIO_COPY operation for shared memory VMAs. It's based on mcopy_atomic_pte with adjustments necessary for shared memory pages. Link: http://lkml.kernel.org/r/20161216144821.5183-32-aarcange@xxxxxxxxxx Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: "Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx> Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx> Cc: Michael Rapoport <RAPOPORT@xxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/userfaultfd.c | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-) diff -puN mm/userfaultfd.c~userfaultfd-shmem-use-shmem_mcopy_atomic_pte-for-shared-memory mm/userfaultfd.c --- a/mm/userfaultfd.c~userfaultfd-shmem-use-shmem_mcopy_atomic_pte-for-shared-memory +++ a/mm/userfaultfd.c @@ -16,6 +16,7 @@ #include <linux/mmu_notifier.h> #include <linux/hugetlb.h> #include <linux/pagemap.h> +#include <linux/shmem_fs.h> #include <asm/tlbflush.h> #include "internal.h" @@ -369,7 +370,9 @@ retry: */ err = -EINVAL; dst_vma = find_vma(dst_mm, dst_start); - if (!dst_vma || (dst_vma->vm_flags & VM_SHARED)) + if (!dst_vma) + goto out_unlock; + if (!vma_is_shmem(dst_vma) && dst_vma->vm_flags & VM_SHARED) goto out_unlock; if (dst_start < dst_vma->vm_start || dst_start + len > dst_vma->vm_end) @@ -394,11 +397,7 @@ retry: if (!dst_vma->vm_userfaultfd_ctx.ctx) goto out_unlock; - /* - * FIXME: only allow copying on anonymous vmas, tmpfs should - * be added. - */ - if (!vma_is_anonymous(dst_vma)) + if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma)) goto out_unlock; /* @@ -407,7 +406,7 @@ retry: * dst_vma. */ err = -ENOMEM; - if (unlikely(anon_vma_prepare(dst_vma))) + if (vma_is_anonymous(dst_vma) && unlikely(anon_vma_prepare(dst_vma))) goto out_unlock; while (src_addr < src_start + len) { @@ -444,12 +443,21 @@ retry: BUG_ON(pmd_none(*dst_pmd)); BUG_ON(pmd_trans_huge(*dst_pmd)); - if (!zeropage) - err = mcopy_atomic_pte(dst_mm, dst_pmd, dst_vma, - dst_addr, src_addr, &page); - else - err = mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma, - dst_addr); + if (vma_is_anonymous(dst_vma)) { + if (!zeropage) + err = mcopy_atomic_pte(dst_mm, dst_pmd, dst_vma, + dst_addr, src_addr, + &page); + else + err = mfill_zeropage_pte(dst_mm, dst_pmd, + dst_vma, dst_addr); + } else { + err = -EINVAL; /* if zeropage is true return -EINVAL */ + if (likely(!zeropage)) + err = shmem_mcopy_atomic_pte(dst_mm, dst_pmd, + dst_vma, dst_addr, + src_addr, &page); + } cond_resched(); _ -- 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
