From 47d9644de92c1aa9dcd791203397b161c67096ca Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Fri, 20 Jan 2023 11:26:28 -0500 Subject: nommu: convert nommu to using the vma iterator Gain type safety in nommu by using the vma_iterator and not the maple tree directly. Link: https://lkml.kernel.org/r/20230120162650.984577-28-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Signed-off-by: Andrew Morton --- mm/nommu.c | 79 ++++++++++++++++++++++++-------------------------------------- 1 file changed, 31 insertions(+), 48 deletions(-) (limited to 'mm/nommu.c') diff --git a/mm/nommu.c b/mm/nommu.c index 0481922fe66e..7a52a7c37009 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -544,19 +544,6 @@ static void put_nommu_region(struct vm_region *region) __put_nommu_region(region); } -void vma_mas_store(struct vm_area_struct *vma, struct ma_state *mas) -{ - mas_set_range(mas, vma->vm_start, vma->vm_end - 1); - mas_store_prealloc(mas, vma); -} - -void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas) -{ - mas->index = vma->vm_start; - mas->last = vma->vm_end - 1; - mas_store_prealloc(mas, NULL); -} - static void setup_vma_to_mm(struct vm_area_struct *vma, struct mm_struct *mm) { vma->vm_mm = mm; @@ -574,13 +561,13 @@ static void setup_vma_to_mm(struct vm_area_struct *vma, struct mm_struct *mm) } /* - * mas_add_vma_to_mm() - Maple state variant of add_mas_to_mm(). - * @mas: The maple state with preallocations. + * vmi_add_vma_to_mm() - VMA Iterator variant of add_vmi_to_mm(). + * @vmi: The VMA iterator * @mm: The mm_struct * @vma: The vma to add * */ -static void mas_add_vma_to_mm(struct ma_state *mas, struct mm_struct *mm, +static void vmi_add_vma_to_mm(struct vma_iterator *vmi, struct mm_struct *mm, struct vm_area_struct *vma) { BUG_ON(!vma->vm_region); @@ -589,7 +576,7 @@ static void mas_add_vma_to_mm(struct ma_state *mas, struct mm_struct *mm, mm->map_count++; /* add the VMA to the tree */ - vma_mas_store(vma, mas); + vma_iter_store(vmi, vma); } /* @@ -600,14 +587,14 @@ static void mas_add_vma_to_mm(struct ma_state *mas, struct mm_struct *mm, */ static int add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma) { - MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_end); + VMA_ITERATOR(vmi, mm, vma->vm_start); - if (mas_preallocate(&mas, GFP_KERNEL)) { + if (vma_iter_prealloc(&vmi)) { pr_warn("Allocation of vma tree for process %d failed\n", current->pid); return -ENOMEM; } - mas_add_vma_to_mm(&mas, mm, vma); + vmi_add_vma_to_mm(&vmi, mm, vma); return 0; } @@ -626,14 +613,15 @@ static void cleanup_vma_from_mm(struct vm_area_struct *vma) i_mmap_unlock_write(mapping); } } + /* * delete a VMA from its owning mm_struct and address space */ static int delete_vma_from_mm(struct vm_area_struct *vma) { - MA_STATE(mas, &vma->vm_mm->mm_mt, 0, 0); + VMA_ITERATOR(vmi, vma->vm_mm, vma->vm_start); - if (mas_preallocate(&mas, GFP_KERNEL)) { + if (vma_iter_prealloc(&vmi)) { pr_warn("Allocation of vma tree for process %d failed\n", current->pid); return -ENOMEM; @@ -641,10 +629,9 @@ static int delete_vma_from_mm(struct vm_area_struct *vma) cleanup_vma_from_mm(vma); /* remove from the MM's tree and list */ - vma_mas_remove(vma, &mas); + vma_iter_clear(&vmi, vma->vm_start, vma->vm_end); return 0; } - /* * destroy a VMA record */ @@ -675,9 +662,9 @@ EXPORT_SYMBOL(find_vma_intersection); */ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) { - MA_STATE(mas, &mm->mm_mt, addr, addr); + VMA_ITERATOR(vmi, mm, addr); - return mas_walk(&mas); + return vma_iter_load(&vmi); } EXPORT_SYMBOL(find_vma); @@ -709,9 +696,9 @@ static struct vm_area_struct *find_vma_exact(struct mm_struct *mm, { struct vm_area_struct *vma; unsigned long end = addr + len; - MA_STATE(mas, &mm->mm_mt, addr, addr); + VMA_ITERATOR(vmi, mm, addr); - vma = mas_walk(&mas); + vma = vma_iter_load(&vmi); if (!vma) return NULL; if (vma->vm_start != addr) @@ -1062,7 +1049,7 @@ unsigned long do_mmap(struct file *file, vm_flags_t vm_flags; unsigned long capabilities, result; int ret; - MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); + VMA_ITERATOR(vmi, current->mm, 0); *populate = 0; @@ -1091,8 +1078,8 @@ unsigned long do_mmap(struct file *file, if (!vma) goto error_getting_vma; - if (mas_preallocate(&mas, GFP_KERNEL)) - goto error_maple_preallocate; + if (vma_iter_prealloc(&vmi)) + goto error_vma_iter_prealloc; region->vm_usage = 1; region->vm_flags = vm_flags; @@ -1234,7 +1221,7 @@ unsigned long do_mmap(struct file *file, current->mm->total_vm += len >> PAGE_SHIFT; share: - mas_add_vma_to_mm(&mas, current->mm, vma); + vmi_add_vma_to_mm(&vmi, current->mm, vma); /* we flush the region from the icache only when the first executable * mapping of it is made */ @@ -1250,7 +1237,7 @@ share: error_just_free: up_write(&nommu_region_sem); error: - mas_destroy(&mas); + vma_iter_free(&vmi); if (region->vm_file) fput(region->vm_file); kmem_cache_free(vm_region_jar, region); @@ -1278,7 +1265,7 @@ error_getting_region: show_free_areas(0, NULL); return -ENOMEM; -error_maple_preallocate: +error_vma_iter_prealloc: kmem_cache_free(vm_region_jar, region); vm_area_free(vma); pr_warn("Allocation of vma tree for process %d failed\n", current->pid); @@ -1344,20 +1331,18 @@ SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) * split a vma into two pieces at address 'addr', a new vma is allocated either * for the first part or the tail. */ -int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long addr, int new_below) +int vmi_split_vma(struct vma_iterator *vmi, struct mm_struct *mm, + struct vm_area_struct *vma, unsigned long addr, int new_below) { struct vm_area_struct *new; struct vm_region *region; unsigned long npages; - MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_end); /* we're only permitted to split anonymous regions (these should have * only a single usage on the region) */ if (vma->vm_file) return -ENOMEM; - mm = vma->vm_mm; if (mm->map_count >= sysctl_max_map_count) return -ENOMEM; @@ -1369,10 +1354,10 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, if (!new) goto err_vma_dup; - if (mas_preallocate(&mas, GFP_KERNEL)) { + if (vma_iter_prealloc(vmi)) { pr_warn("Allocation of vma tree for process %d failed\n", current->pid); - goto err_mas_preallocate; + goto err_vmi_preallocate; } /* most fields are the same, copy all, and then fixup */ @@ -1406,13 +1391,11 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, setup_vma_to_mm(vma, mm); setup_vma_to_mm(new, mm); - mas_set_range(&mas, vma->vm_start, vma->vm_end - 1); - mas_store(&mas, vma); - vma_mas_store(new, &mas); + vma_iter_store(vmi, new); mm->map_count++; return 0; -err_mas_preallocate: +err_vmi_preallocate: vm_area_free(new); err_vma_dup: kmem_cache_free(vm_region_jar, region); @@ -1466,7 +1449,7 @@ static int shrink_vma(struct mm_struct *mm, */ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf) { - MA_STATE(mas, &mm->mm_mt, start, start); + VMA_ITERATOR(vmi, mm, start); struct vm_area_struct *vma; unsigned long end; int ret = 0; @@ -1478,7 +1461,7 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list end = start + len; /* find the first potentially overlapping VMA */ - vma = mas_find(&mas, end - 1); + vma = vma_find(&vmi, end); if (!vma) { static int limit; if (limit < 5) { @@ -1497,7 +1480,7 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list return -EINVAL; if (end == vma->vm_end) goto erase_whole_vma; - vma = mas_next(&mas, end - 1); + vma = vma_find(&vmi, end); } while (vma); return -EINVAL; } else { @@ -1511,7 +1494,7 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list if (end != vma->vm_end && offset_in_page(end)) return -EINVAL; if (start != vma->vm_start && end != vma->vm_end) { - ret = split_vma(mm, vma, start, 1); + ret = vmi_split_vma(&vmi, mm, vma, start, 1); if (ret < 0) return ret; } -- cgit v1.2.3