Re: [PATCH v1 1/1] clk: fractional-divider: Move mask calculations out of lock

From: Stephen Boyd
Date: Fri Mar 08 2024 - 20:06:19 EST


Quoting Andy Shevchenko (2024-03-03 04:14:10)
> There is no need to calculate masks under the lock taken.
> Move them out of it.
>
> Signed-off-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> ---

Applied to clk-next

> diff --git a/drivers/clk/clk-fractional-divider.c b/drivers/clk/clk-fractional-divider.c
> index a0178182fc72..da057172cc90 100644
> --- a/drivers/clk/clk-fractional-divider.c
> +++ b/drivers/clk/clk-fractional-divider.c
> @@ -195,14 +195,14 @@ static int clk_fd_set_rate(struct clk_hw *hw, unsigned long rate,
> n--;
> }
>
> + mmask = GENMASK(fd->mwidth - 1, 0) << fd->mshift;
> + nmask = GENMASK(fd->nwidth - 1, 0) << fd->nshift;
> +
> if (fd->lock)
> spin_lock_irqsave(fd->lock, flags);
> else
> __acquire(fd->lock);
>
> - mmask = GENMASK(fd->mwidth - 1, 0) << fd->mshift;
> - nmask = GENMASK(fd->nwidth - 1, 0) << fd->nshift;
> -
> val = clk_fd_readl(fd);
> val &= ~(mmask | nmask);
> val |= (m << fd->mshift) | (n << fd->nshift);

Should we pre-calculate the mask and shift values too!?