Re: [PATCH 1/3] lib: Introduce copy_from_back()

[Christoph Hellwig]

> +#define FAST_COPY_SAFEGUARD_SIZE (sizeof(long) * 2 - 1)
> +
> +#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
> +
> +/*
> + * The caller must ensure that the output buffer has enough space (len + FAST_COPY_SAFEGUARD_SIZE),
> + * so we can write 2 words per loop without overflowing the output buffer
> + */
> +static __always_inline u8 *copy_from_back_fast(u8 *out, size_t dist, size_t len)

The code is pretty unreadable with these longs lines.  Please stick to
the normal 80 char limit.