From 643aa36eadebdcdcaeecf538f0549a619ad78ea0 Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Sat, 30 Nov 2019 17:57:55 -0800 Subject: [PATCH] userfaultfd: wrap the common dst_vma check into an inlined function When doing UFFDIO_COPY, it is necessary to find the correct destination vma and make sure fault range is in it. Since there are two places need to do the same task, just wrap those common check into an inlined function. Link: http://lkml.kernel.org/r/20190927070032.2129-3-richardw.yang@linux.intel.com Signed-off-by: Wei Yang Reviewed-by: Mike Kravetz Cc: Andrea Arcangeli Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/userfaultfd.c | 56 +++++++++++++++++++++++++++--------------------- 1 file changed, 32 insertions(+), 24 deletions(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 07f44555fd03..a10aa8563e41 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -18,6 +18,36 @@ #include #include "internal.h" +static __always_inline +struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm, + unsigned long dst_start, + unsigned long len) +{ + /* + * Make sure that the dst range is both valid and fully within a + * single existing vma. + */ + struct vm_area_struct *dst_vma; + + dst_vma = find_vma(dst_mm, dst_start); + if (!dst_vma) + return NULL; + + if (dst_start < dst_vma->vm_start || + dst_start + len > dst_vma->vm_end) + return NULL; + + /* + * Check the vma is registered in uffd, this is required to + * enforce the VM_MAYWRITE check done at uffd registration + * time. + */ + if (!dst_vma->vm_userfaultfd_ctx.ctx) + return NULL; + + return dst_vma; +} + static int mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, struct vm_area_struct *dst_vma, @@ -220,20 +250,9 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, */ if (!dst_vma) { err = -ENOENT; - dst_vma = find_vma(dst_mm, dst_start); + dst_vma = find_dst_vma(dst_mm, dst_start, len); if (!dst_vma || !is_vm_hugetlb_page(dst_vma)) goto out_unlock; - /* - * Check the vma is registered in uffd, this is - * required to enforce the VM_MAYWRITE check done at - * uffd registration time. - */ - if (!dst_vma->vm_userfaultfd_ctx.ctx) - goto out_unlock; - - if (dst_start < dst_vma->vm_start || - dst_start + len > dst_vma->vm_end) - goto out_unlock; err = -EINVAL; if (vma_hpagesize != vma_kernel_pagesize(dst_vma)) @@ -468,20 +487,9 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm, * both valid and fully within a single existing vma. */ err = -ENOENT; - dst_vma = find_vma(dst_mm, dst_start); + dst_vma = find_dst_vma(dst_mm, dst_start, len); if (!dst_vma) goto out_unlock; - /* - * Check the vma is registered in uffd, this is required to - * enforce the VM_MAYWRITE check done at uffd registration - * time. - */ - if (!dst_vma->vm_userfaultfd_ctx.ctx) - goto out_unlock; - - if (dst_start < dst_vma->vm_start || - dst_start + len > dst_vma->vm_end) - goto out_unlock; err = -EINVAL; /* -- GitLab