On Fri, May 27 2016, Dan Carpenter wrote:
> This loop is supposed to set all the .num values to -1 but it's doesn't
> set the first element and it sets one element beyond the end of the
> array. Really there is no reason for it to be done backwards. And
> "ret" is the wrong variable to use for an iterator.
>
> Fixes: ddf8abd25994 ('USB: f_fs: the FunctionFS driver')
> Signed-off-by: Dan Carpenter <[email protected]>
Acked-by: Michal Nazarewicz <[email protected]>
How on Earth could I have made that mistake is beyond my
comprehension. O_o On second thought, things being beyond one’s
comprehension is probably how bugs are introduced…
> ---
> I just spotted this reviewing the code, I have not tested it. Please
> review carefully, the vla_ptr() macro is difficult to understand.
Yeah. In retrospect I’m not sure savings in memory those macros bring
offset time engineers spent trying to understand them. Damn you clang!
> diff --git a/drivers/usb/gadget/function/f_fs.c
> b/drivers/usb/gadget/function/f_fs.c
> index 73515d5..7fff81a 100644
> --- a/drivers/usb/gadget/function/f_fs.c
> +++ b/drivers/usb/gadget/function/f_fs.c
> @@ -2777,11 +2777,11 @@ static int _ffs_func_bind(struct usb_configuration *c,
> ffs->raw_descs_length);
>
> memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
> - for (ret = ffs->eps_count; ret; --ret) {
> + for (i = 0; i < ffs->eps_count; i++) {
> struct ffs_ep *ptr;
>
> ptr = vla_ptr(vlabuf, d, eps);
As pointed by Walter, this could be moved outside. Maybe
i = ffs->eps_count;
for (struct ffs_ep *ptr = vla_ptr(vlabuf, d, eps); i; ++ptr, --i)
ptr->num = -1;
> - ptr[ret].num = -1;
> + ptr[i].num = -1;
> }
>
> /* Save pointers
--
Best regards
ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ
«If at first you don’t succeed, give up skydiving»
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