From 11a9b90274f6a50f7877a61c8e82dd3c845ff1dd Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Fri, 20 Jan 2023 11:26:17 -0500 Subject: userfaultfd: use vma iterator Use the vma iterator so that the iterator can be invalidated or updated to avoid each caller doing so. Link: https://lkml.kernel.org/r/20230120162650.984577-17-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Signed-off-by: Andrew Morton --- fs/userfaultfd.c | 87 +++++++++++++++++++++----------------------------------- 1 file changed, 33 insertions(+), 54 deletions(-) (limited to 'fs/userfaultfd.c') diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 15a5bf765d43..4334bd35984d 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -883,7 +883,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file) /* len == 0 means wake all */ struct userfaultfd_wake_range range = { .len = 0, }; unsigned long new_flags; - MA_STATE(mas, &mm->mm_mt, 0, 0); + VMA_ITERATOR(vmi, mm, 0); WRITE_ONCE(ctx->released, true); @@ -900,7 +900,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file) */ mmap_write_lock(mm); prev = NULL; - mas_for_each(&mas, vma, ULONG_MAX) { + for_each_vma(vmi, vma) { cond_resched(); BUG_ON(!!vma->vm_userfaultfd_ctx.ctx ^ !!(vma->vm_flags & __VM_UFFD_FLAGS)); @@ -909,13 +909,12 @@ static int userfaultfd_release(struct inode *inode, struct file *file) continue; } new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS; - prev = vma_merge(mm, prev, vma->vm_start, vma->vm_end, + prev = vmi_vma_merge(&vmi, mm, prev, vma->vm_start, vma->vm_end, new_flags, vma->anon_vma, vma->vm_file, vma->vm_pgoff, vma_policy(vma), NULL_VM_UFFD_CTX, anon_vma_name(vma)); if (prev) { - mas_pause(&mas); vma = prev; } else { prev = vma; @@ -1302,7 +1301,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, bool found; bool basic_ioctls; unsigned long start, end, vma_end; - MA_STATE(mas, &mm->mm_mt, 0, 0); + struct vma_iterator vmi; user_uffdio_register = (struct uffdio_register __user *) arg; @@ -1344,17 +1343,13 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, if (!mmget_not_zero(mm)) goto out; + ret = -EINVAL; mmap_write_lock(mm); - mas_set(&mas, start); - vma = mas_find(&mas, ULONG_MAX); + vma_iter_init(&vmi, mm, start); + vma = vma_find(&vmi, end); if (!vma) goto out_unlock; - /* check that there's at least one vma in the range */ - ret = -EINVAL; - if (vma->vm_start >= end) - goto out_unlock; - /* * If the first vma contains huge pages, make sure start address * is aligned to huge page size. @@ -1371,7 +1366,8 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, */ found = false; basic_ioctls = false; - for (cur = vma; cur; cur = mas_next(&mas, end - 1)) { + cur = vma; + do { cond_resched(); BUG_ON(!!cur->vm_userfaultfd_ctx.ctx ^ @@ -1428,16 +1424,14 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, basic_ioctls = true; found = true; - } + } for_each_vma_range(vmi, cur, end); BUG_ON(!found); - mas_set(&mas, start); - prev = mas_prev(&mas, 0); - if (prev != vma) - mas_next(&mas, ULONG_MAX); + vma_iter_set(&vmi, start); + prev = vma_prev(&vmi); ret = 0; - do { + for_each_vma_range(vmi, vma, end) { cond_resched(); BUG_ON(!vma_can_userfault(vma, vm_flags)); @@ -1458,30 +1452,25 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, vma_end = min(end, vma->vm_end); new_flags = (vma->vm_flags & ~__VM_UFFD_FLAGS) | vm_flags; - prev = vma_merge(mm, prev, start, vma_end, new_flags, + prev = vmi_vma_merge(&vmi, mm, prev, start, vma_end, new_flags, vma->anon_vma, vma->vm_file, vma->vm_pgoff, vma_policy(vma), ((struct vm_userfaultfd_ctx){ ctx }), anon_vma_name(vma)); if (prev) { /* vma_merge() invalidated the mas */ - mas_pause(&mas); vma = prev; goto next; } if (vma->vm_start < start) { - ret = split_vma(mm, vma, start, 1); + ret = vmi_split_vma(&vmi, mm, vma, start, 1); if (ret) break; - /* split_vma() invalidated the mas */ - mas_pause(&mas); } if (vma->vm_end > end) { - ret = split_vma(mm, vma, end, 0); + ret = vmi_split_vma(&vmi, mm, vma, end, 0); if (ret) break; - /* split_vma() invalidated the mas */ - mas_pause(&mas); } next: /* @@ -1498,8 +1487,8 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, skip: prev = vma; start = vma->vm_end; - vma = mas_next(&mas, end - 1); - } while (vma); + } + out_unlock: mmap_write_unlock(mm); mmput(mm); @@ -1543,7 +1532,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, bool found; unsigned long start, end, vma_end; const void __user *buf = (void __user *)arg; - MA_STATE(mas, &mm->mm_mt, 0, 0); + struct vma_iterator vmi; ret = -EFAULT; if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister))) @@ -1562,14 +1551,10 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, goto out; mmap_write_lock(mm); - mas_set(&mas, start); - vma = mas_find(&mas, ULONG_MAX); - if (!vma) - goto out_unlock; - - /* check that there's at least one vma in the range */ ret = -EINVAL; - if (vma->vm_start >= end) + vma_iter_init(&vmi, mm, start); + vma = vma_find(&vmi, end); + if (!vma) goto out_unlock; /* @@ -1587,8 +1572,8 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, * Search for not compatible vmas. */ found = false; - ret = -EINVAL; - for (cur = vma; cur; cur = mas_next(&mas, end - 1)) { + cur = vma; + do { cond_resched(); BUG_ON(!!cur->vm_userfaultfd_ctx.ctx ^ @@ -1605,16 +1590,13 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, goto out_unlock; found = true; - } + } for_each_vma_range(vmi, cur, end); BUG_ON(!found); - mas_set(&mas, start); - prev = mas_prev(&mas, 0); - if (prev != vma) - mas_next(&mas, ULONG_MAX); - + vma_iter_set(&vmi, start); + prev = vma_prev(&vmi); ret = 0; - do { + for_each_vma_range(vmi, vma, end) { cond_resched(); BUG_ON(!vma_can_userfault(vma, vma->vm_flags)); @@ -1650,26 +1632,23 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, uffd_wp_range(mm, vma, start, vma_end - start, false); new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS; - prev = vma_merge(mm, prev, start, vma_end, new_flags, + prev = vmi_vma_merge(&vmi, mm, prev, start, vma_end, new_flags, vma->anon_vma, vma->vm_file, vma->vm_pgoff, vma_policy(vma), NULL_VM_UFFD_CTX, anon_vma_name(vma)); if (prev) { vma = prev; - mas_pause(&mas); goto next; } if (vma->vm_start < start) { - ret = split_vma(mm, vma, start, 1); + ret = vmi_split_vma(&vmi, mm, vma, start, 1); if (ret) break; - mas_pause(&mas); } if (vma->vm_end > end) { - ret = split_vma(mm, vma, end, 0); + ret = vmi_split_vma(&vmi, mm, vma, end, 0); if (ret) break; - mas_pause(&mas); } next: /* @@ -1683,8 +1662,8 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, skip: prev = vma; start = vma->vm_end; - vma = mas_next(&mas, end - 1); - } while (vma); + } + out_unlock: mmap_write_unlock(mm); mmput(mm); -- cgit