usercopy: Cast pointer to an integer once

Get rid of a lot of annoying casts by setting 'addr' once at the top
of the function.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Tested-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220612213227.3881769-3-willy@infradead.org

diff --git a/mm/usercopy.c b/mm/usercopy.c
index cd4b41d..30a4db3 100644 (file)
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -161,26 +161,27 @@ static inline void check_bogus_address(const unsigned long ptr, unsigned long n,
 static inline void check_heap_object(const void *ptr, unsigned long n,
                                     bool to_user)
 {
+       uintptr_t addr = (uintptr_t)ptr;
        struct folio *folio;
 
        if (is_kmap_addr(ptr)) {
-               unsigned long page_end = (unsigned long)ptr | (PAGE_SIZE - 1);
+               unsigned long page_end = addr | (PAGE_SIZE - 1);
 
-               if ((unsigned long)ptr + n - 1 > page_end)
+               if (addr + n - 1 > page_end)
                        usercopy_abort("kmap", NULL, to_user,
                                        offset_in_page(ptr), n);
                return;
        }
 
        if (is_vmalloc_addr(ptr)) {
-               struct vmap_area *area = find_vmap_area((unsigned long)ptr);
+               struct vmap_area *area = find_vmap_area(addr);
                unsigned long offset;
 
                if (!area)
                        usercopy_abort("vmalloc", "no area", to_user, 0, n);
 
-               offset = (unsigned long)ptr - area->va_start;
-               if ((unsigned long)ptr + n > area->va_end)
+               offset = addr - area->va_start;
+               if (addr + n > area->va_end)
                        usercopy_abort("vmalloc", NULL, to_user, offset, n);
                return;
        }