Re: [PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()

Andy Shevchenko
2019-04-03T11:15:29Z

On Wed, Apr 03, 2019 at 07:45:36AM +0300, Yury Norov wrote:
> Currently we parse user data byte after byte which leads to
> overcomplification of parsing algorithm. The only user of
> bitmap_parselist_user() is not performance-critical, and so we
> can copy user data to kernel buffer and simply call
> bitmap_parselist(). This rework lets us unify and simplify
> bitmap_parselist() and bitmap_parselist_user(), which is done
> in the following patch.

> + buf = kmalloc(ulen + 1, GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> +
> + buf[ulen] = 0;
> +
> + ret = copy_from_user(buf, ubuf, ulen);
> + if (ret)
> + goto out;

Why not memdup_user() ?

--
With Best Regards,
Andy Shevchenko