Re: [PATCH] mm: refactor __vunmap() to avoid duplicated call to find_vm_area()

From: Ira Weiny
Date: Wed May 15 2019 - 13:36:36 EST


>
> -/* Handle removing and resetting vm mappings related to the vm_struct. */
> -static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
> +/* Handle removing and resetting vm mappings related to the va->vm vm_struct. */
> +static void vm_remove_mappings(struct vmap_area *va, int deallocate_pages)

Does this apply to 5.1? I'm confused because I can't find vm_remove_mappings()
in 5.1.

Ira

> {
> + struct vm_struct *area = va->vm;
> unsigned long addr = (unsigned long)area->addr;
> unsigned long start = ULONG_MAX, end = 0;
> int flush_reset = area->flags & VM_FLUSH_RESET_PERMS;
> @@ -2138,7 +2143,7 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
> set_memory_rw(addr, area->nr_pages);
> }
>
> - remove_vm_area(area->addr);
> + __remove_vm_area(va);
>
> /* If this is not VM_FLUSH_RESET_PERMS memory, no need for the below. */
> if (!flush_reset)
> @@ -2178,6 +2183,7 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
> static void __vunmap(const void *addr, int deallocate_pages)
> {
> struct vm_struct *area;
> + struct vmap_area *va;
>
> if (!addr)
> return;
> @@ -2186,17 +2192,18 @@ static void __vunmap(const void *addr, int deallocate_pages)
> addr))
> return;
>
> - area = find_vm_area(addr);
> - if (unlikely(!area)) {
> + va = find_vmap_area((unsigned long)addr);
> + if (unlikely(!va || !(va->flags & VM_VM_AREA))) {
> WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
> addr);
> return;
> }
>
> + area = va->vm;
> debug_check_no_locks_freed(area->addr, get_vm_area_size(area));
> debug_check_no_obj_freed(area->addr, get_vm_area_size(area));
>
> - vm_remove_mappings(area, deallocate_pages);
> + vm_remove_mappings(va, deallocate_pages);
>
> if (deallocate_pages) {
> int i;
> @@ -2212,7 +2219,6 @@ static void __vunmap(const void *addr, int deallocate_pages)
> }
>
> kfree(area);
> - return;
> }
>
> static inline void __vfree_deferred(const void *addr)
> --
> 2.20.1
>