From 92fed82047d7febc83614a9579c37f1ce80442be Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Fri, 20 Jan 2023 11:26:09 -0500 Subject: mm/mmap: convert brk to use vma iterator Use the vma iterator API for the brk() system call. This will provide type safety at compile time. Link: https://lkml.kernel.org/r/20230120162650.984577-9-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Signed-off-by: Andrew Morton --- mm/mmap.c | 48 +++++++++++++++++++++++------------------------- 1 file changed, 23 insertions(+), 25 deletions(-) (limited to 'mm') diff --git a/mm/mmap.c b/mm/mmap.c index db70f3e2181e..94a477a55109 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -180,10 +180,10 @@ static int check_brk_limits(unsigned long addr, unsigned long len) return mlock_future_check(current->mm, current->mm->def_flags, len); } -static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma, +static int do_brk_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, unsigned long newbrk, unsigned long oldbrk, struct list_head *uf); -static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *brkvma, +static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *brkvma, unsigned long addr, unsigned long request, unsigned long flags); SYSCALL_DEFINE1(brk, unsigned long, brk) { @@ -194,7 +194,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) bool populate; bool downgraded = false; LIST_HEAD(uf); - MA_STATE(mas, &mm->mm_mt, 0, 0); + struct vma_iterator vmi; if (mmap_write_lock_killable(mm)) return -EINTR; @@ -242,8 +242,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) int ret; /* Search one past newbrk */ - mas_set(&mas, newbrk); - brkvma = mas_find(&mas, oldbrk); + vma_iter_init(&vmi, mm, newbrk); + brkvma = vma_find(&vmi, oldbrk); if (!brkvma || brkvma->vm_start >= oldbrk) goto out; /* mapping intersects with an existing non-brk vma. */ /* @@ -252,7 +252,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) * before calling do_brk_munmap(). */ mm->brk = brk; - ret = do_brk_munmap(&mas, brkvma, newbrk, oldbrk, &uf); + ret = do_brk_munmap(&vmi, brkvma, newbrk, oldbrk, &uf); if (ret == 1) { downgraded = true; goto success; @@ -270,14 +270,14 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) * Only check if the next VMA is within the stack_guard_gap of the * expansion area */ - mas_set(&mas, oldbrk); - next = mas_find(&mas, newbrk - 1 + PAGE_SIZE + stack_guard_gap); + vma_iter_init(&vmi, mm, oldbrk); + next = vma_find(&vmi, newbrk + PAGE_SIZE + stack_guard_gap); if (next && newbrk + PAGE_SIZE > vm_start_gap(next)) goto out; - brkvma = mas_prev(&mas, mm->start_brk); + brkvma = vma_prev_limit(&vmi, mm->start_brk); /* Ok, looks good - let it rip. */ - if (do_brk_flags(&mas, brkvma, oldbrk, newbrk - oldbrk, 0) < 0) + if (do_brk_flags(&vmi, brkvma, oldbrk, newbrk - oldbrk, 0) < 0) goto out; mm->brk = brk; @@ -2917,8 +2917,8 @@ out: } /* - * brk_munmap() - Unmap a partial vma. - * @mas: The maple tree state. + * brk_munmap() - Unmap a full or partial vma. + * @vmi: The vma iterator * @vma: The vma to be modified * @newbrk: the start of the address to unmap * @oldbrk: The end of the address to unmap @@ -2928,7 +2928,7 @@ out: * unmaps a partial VMA mapping. Does not handle alignment, downgrades lock if * possible. */ -static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma, +static int do_brk_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, unsigned long newbrk, unsigned long oldbrk, struct list_head *uf) { @@ -2936,14 +2936,14 @@ static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma, int ret; arch_unmap(mm, newbrk, oldbrk); - ret = do_mas_align_munmap(mas, vma, mm, newbrk, oldbrk, uf, true); + ret = do_mas_align_munmap(&vmi->mas, vma, mm, newbrk, oldbrk, uf, true); validate_mm_mt(mm); return ret; } /* * do_brk_flags() - Increase the brk vma if the flags match. - * @mas: The maple tree state. + * @vmi: The vma iterator * @addr: The start address * @len: The length of the increase * @vma: The vma, @@ -2953,7 +2953,7 @@ static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma, * do not match then create a new anonymous VMA. Eventually we may be able to * do some brk-specific accounting here. */ -static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma, +static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, unsigned long addr, unsigned long len, unsigned long flags) { struct mm_struct *mm = current->mm; @@ -2980,8 +2980,7 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma, if (vma && vma->vm_end == addr && !vma_policy(vma) && can_vma_merge_after(vma, flags, NULL, NULL, addr >> PAGE_SHIFT, NULL_VM_UFFD_CTX, NULL)) { - mas_set_range(mas, vma->vm_start, addr + len - 1); - if (mas_preallocate(mas, GFP_KERNEL)) + if (vma_iter_prealloc(vmi)) goto unacct_fail; vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0); @@ -2991,7 +2990,7 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma, } vma->vm_end = addr + len; vma->vm_flags |= VM_SOFTDIRTY; - mas_store_prealloc(mas, vma); + vma_iter_store(vmi, vma); if (vma->anon_vma) { anon_vma_interval_tree_post_update_vma(vma); @@ -3012,8 +3011,7 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma, vma->vm_pgoff = addr >> PAGE_SHIFT; vma->vm_flags = flags; vma->vm_page_prot = vm_get_page_prot(flags); - mas_set_range(mas, vma->vm_start, addr + len - 1); - if (mas_store_gfp(mas, vma, GFP_KERNEL)) + if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL)) goto mas_store_fail; mm->map_count++; @@ -3042,7 +3040,7 @@ int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags) int ret; bool populate; LIST_HEAD(uf); - MA_STATE(mas, &mm->mm_mt, addr, addr); + VMA_ITERATOR(vmi, mm, addr); len = PAGE_ALIGN(request); if (len < request) @@ -3061,12 +3059,12 @@ int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags) if (ret) goto limits_failed; - ret = do_mas_munmap(&mas, mm, addr, len, &uf, 0); + ret = do_mas_munmap(&vmi.mas, mm, addr, len, &uf, 0); if (ret) goto munmap_failed; - vma = mas_prev(&mas, 0); - ret = do_brk_flags(&mas, vma, addr, len, flags); + vma = vma_prev(&vmi); + ret = do_brk_flags(&vmi, vma, addr, len, flags); populate = ((mm->def_flags & VM_LOCKED) != 0); mmap_write_unlock(mm); userfaultfd_unmap_complete(mm, &uf); -- cgit v1.2.3