On Tue, Aug 31, 2021 at 07:40:58PM -0700, Joe Perches wrote: > On Tue, 2021-08-31 at 21:15 +0300, Kari Argillander wrote: > > If we do not use kmalloc_array we get checkpatch warning. It is also > > little safer if something goes wrong with coding. > [] > > diff --git a/fs/ntfs3/index.c b/fs/ntfs3/index.c > [] > > @@ -707,7 +707,7 @@ static struct NTFS_DE *hdr_find_e(const struct ntfs_index *indx, > > u16 *ptr; > > int new_slots = ALIGN(2 * nslots, 8); > > > > > > - ptr = kmalloc(sizeof(u16) * new_slots, GFP_NOFS); > > + ptr = kmalloc_array(new_slots, sizeof(u16), GFP_NOFS); > > if (ptr) > > memcpy(ptr, offs, sizeof(u16) * max_idx); > > This multiplication could also overflow. > > Maybe use krealloc? Seems to fit lot better here. But as I was watching this it seems that we do not even need to resize this array. It is quite costly operation compared to what entry compare cost. We just need to compare it and if entry diff > 0 then we start entry table again from zero without need resize array. It may be that we do not even need to allocate memory. We can probably survive with stack, but let's think that later. This can also speed up search a lot. It is quite odd that we always fill whole table and will not never check if we are over. Worst case is very very bad. With this change this will be more like jump search but I think it will be good in this case because we won't need memory allocation. Thanks Joe.
