From: Liam R. Howlett Date: Fri, 5 Aug 2022 20:15:12 +0000 (-0400) Subject: mm/mmap: Use vma_lock() and vma_unlock() in vma_expand() X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=dfa623cad7df6a5bc194f46b4a35e59ad6223c68;p=users%2Fjedix%2Flinux-maple.git mm/mmap: Use vma_lock() and vma_unlock() in vma_expand() Use the new locking functions for vma_expand. Signed-off-by: Liam R. Howlett --- diff --git a/mm/mmap.c b/mm/mmap.c index 88f9904169b8..0a787531e3fc 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -493,119 +493,6 @@ static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma) return 0; } -/* - * vma_expand - Expand an existing VMA - * - * @mas: The maple state - * @vma: The vma to expand - * @start: The start of the vma - * @end: The exclusive end of the vma - * @pgoff: The page offset of vma - * @next: The current of next vma. - * - * Expand @vma to @start and @end. Can expand off the start and end. Will - * expand over @next if it's different from @vma and @end == @next->vm_end. - * Checking if the @vma can expand and merge with @next needs to be handled by - * the caller. - * - * Returns: 0 on success - */ -inline int vma_expand(struct ma_state *mas, struct vm_area_struct *vma, - unsigned long start, unsigned long end, pgoff_t pgoff, - struct vm_area_struct *next) -{ - struct mm_struct *mm = vma->vm_mm; - struct address_space *mapping = NULL; - struct rb_root_cached *root = NULL; - struct anon_vma *anon_vma = vma->anon_vma; - struct file *file = vma->vm_file; - bool remove_next = false; - - if (next && (vma != next) && (end == next->vm_end)) { - remove_next = true; - if (next->anon_vma && !vma->anon_vma) { - int error; - - anon_vma = next->anon_vma; - vma->anon_vma = anon_vma; - error = anon_vma_clone(vma, next); - if (error) - return error; - } - } - - /* Not merging but overwriting any part of next is not handled. */ - VM_BUG_ON(next && !remove_next && next != vma && end > next->vm_start); - /* Only handles expanding */ - VM_BUG_ON(vma->vm_start < start || vma->vm_end > end); - - if (mas_preallocate(mas, vma, GFP_KERNEL)) - goto nomem; - - vma_adjust_trans_huge(vma, start, end, 0); - - if (file) { - mapping = file->f_mapping; - root = &mapping->i_mmap; - uprobe_munmap(vma, vma->vm_start, vma->vm_end); - i_mmap_lock_write(mapping); - } - - if (anon_vma) { - anon_vma_lock_write(anon_vma); - anon_vma_interval_tree_pre_update_vma(vma); - } - - if (file) { - flush_dcache_mmap_lock(mapping); - vma_interval_tree_remove(vma, root); - } - - vma->vm_start = start; - vma->vm_end = end; - vma->vm_pgoff = pgoff; - /* Note: mas must be pointing to the expanding VMA */ - vma_mas_store(vma, mas); - - if (file) { - vma_interval_tree_insert(vma, root); - flush_dcache_mmap_unlock(mapping); - } - - /* Expanding over the next vma */ - if (remove_next && file) { - __remove_shared_vm_struct(next, file, mapping); - } - - if (anon_vma) { - anon_vma_interval_tree_post_update_vma(vma); - anon_vma_unlock_write(anon_vma); - } - - if (file) { - i_mmap_unlock_write(mapping); - uprobe_mmap(vma); - } - - if (remove_next) { - if (file) { - uprobe_munmap(next, next->vm_start, next->vm_end); - fput(file); - } - if (next->anon_vma) - anon_vma_merge(vma, next); - mm->map_count--; - mpol_put(vma_policy(next)); - vm_area_free(next); - } - - validate_mm(mm); - return 0; - -nomem: - return -ENOMEM; -} - /* * lock_vma() - Helper function for locking VMAs prior to altering * @vl: The initialized vma_locking struct @@ -726,6 +613,75 @@ again: uprobe_mmap(vl->insert); } +/* + * vma_expand - Expand an existing VMA + * + * @mas: The maple state + * @vma: The vma to expand + * @start: The start of the vma + * @end: The exclusive end of the vma + * @pgoff: The page offset of vma + * @next: The current of next vma. + * + * Expand @vma to @start and @end. Can expand off the start and end. Will + * expand over @next if it's different from @vma and @end == @next->vm_end. + * Checking if the @vma can expand and merge with @next needs to be handled by + * the caller. + * + * Returns: 0 on success + */ +inline int vma_expand(struct ma_state *mas, struct vm_area_struct *vma, + unsigned long start, unsigned long end, pgoff_t pgoff, + struct vm_area_struct *next) + +{ + struct vma_locking vma_lock; + + memset(&vma_lock, 0, sizeof(vma_lock)); + vma_lock.vma = vma; + vma_lock.anon_vma = vma->anon_vma; + if (next && (vma != next) && (end == next->vm_end)) { + vma_lock.remove = next; + if (next->anon_vma && !vma->anon_vma) { + int error; + + vma_lock.anon_vma = next->anon_vma; + vma->anon_vma = next->anon_vma; + error = anon_vma_clone(vma, next); + if (error) + return error; + } + } + + /* Not merging but overwriting any part of next is not handled. */ + VM_BUG_ON(next && !vma_lock.remove && + next != vma && end > next->vm_start); + /* Only handles expanding */ + VM_BUG_ON(vma->vm_start < start || vma->vm_end > end); + + if (mas_preallocate(mas, vma, GFP_KERNEL)) + goto nomem; + + vma_adjust_trans_huge(vma, start, end, 0); + + vma_lock.file = vma->vm_file; + if (vma_lock.file) + vma_lock.mapping = vma_lock.file->f_mapping; + lock_vma(&vma_lock); + + vma->vm_start = start; + vma->vm_end = end; + vma->vm_pgoff = pgoff; + /* Note: mas must be pointing to the expanding VMA */ + vma_mas_store(vma, mas); + + unlock_vma(&vma_lock, mas, vma->vm_mm); + validate_mm(vma->vm_mm); + return 0; + +nomem: + return -ENOMEM; +} /* * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that * is already present in an i_mmap tree without adjusting the tree.