On 1/15/21 1:37 PM, Claudio Imbrenda wrote:
> Add some asserts to make sure the state is consistent.
>
> Simplify and improve the readability of vm_free.
>
> If a NULL pointer is freed, no operation is performed.
>
> Fixes: 3f6fee0d4da4 ("lib/vmalloc: vmalloc support for handling allocation metadata")
>
> Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Acked-by: Janosch Frank <frankja@xxxxxxxxxx>
> ---
> lib/vmalloc.c | 22 +++++++++++++---------
> 1 file changed, 13 insertions(+), 9 deletions(-)
>
> diff --git a/lib/vmalloc.c b/lib/vmalloc.c
> index 986a34c..6b52790 100644
> --- a/lib/vmalloc.c
> +++ b/lib/vmalloc.c
> @@ -162,13 +162,16 @@ static void *vm_memalign(size_t alignment, size_t size)
> static void vm_free(void *mem)
> {
> struct metadata *m;
> - uintptr_t ptr, end;
> + uintptr_t ptr, page, i;
>
> + if (!mem)
> + return;
> /* the pointer is not page-aligned, it was a single-page allocation */
> if (!IS_ALIGNED((uintptr_t)mem, PAGE_SIZE)) {
> assert(GET_MAGIC(mem) == VM_MAGIC);
> - ptr = virt_to_pte_phys(page_root, mem) & PAGE_MASK;
> - free_page(phys_to_virt(ptr));
> + page = virt_to_pte_phys(page_root, mem) & PAGE_MASK;
> + assert(page);
> + free_page(phys_to_virt(page));
> return;
> }
>
> @@ -176,13 +179,14 @@ static void vm_free(void *mem)
> m = GET_METADATA(mem);
> assert(m->magic == VM_MAGIC);
> assert(m->npages > 0);
> + assert(m->npages < BIT_ULL(BITS_PER_LONG - PAGE_SHIFT));
> /* free all the pages including the metadata page */
> - ptr = (uintptr_t)mem - PAGE_SIZE;
> - end = ptr + m->npages * PAGE_SIZE;
> - for ( ; ptr < end; ptr += PAGE_SIZE)
> - free_page(phys_to_virt(virt_to_pte_phys(page_root, (void *)ptr)));
> - /* free the last one separately to avoid overflow issues */
> - free_page(phys_to_virt(virt_to_pte_phys(page_root, (void *)ptr)));
> + ptr = (uintptr_t)m & PAGE_MASK;
> + for (i = 0 ; i < m->npages + 1; i++, ptr += PAGE_SIZE) {
s/i < m->npages + 1/i <= m->npages/ ?
> + page = virt_to_pte_phys(page_root, (void *)ptr) & PAGE_MASK;
> + assert(page);
> + free_page(phys_to_virt(page));
> + }
> }
>
> static struct alloc_ops vmalloc_ops = {
>
