Re: [PATCH v5] locking/memory-barriers.txt: Improve documentation for writel() example

From: Paul E. McKenney
Date: Wed Nov 02 2022 - 16:30:53 EST


On Wed, Nov 02, 2022 at 06:05:54AM +0000, Will Deacon wrote:
> On Thu, Oct 27, 2022 at 11:10:00PM +0300, Parav Pandit wrote:
> > The cited commit describes that when using writel(), explicit wmb()
> > is not needed. wmb() is an expensive barrier. writel() uses the needed
> > platform specific barrier instead of wmb().
> >
> > writeX() section of "KERNEL I/O BARRIER EFFECTS" already describes
> > ordering of I/O accessors with MMIO writes.
> >
> > Hence add the comment for pseudo code of writel() and remove confusing
> > text around writel() and wmb().
> >
> > commit 5846581e3563 ("locking/memory-barriers.txt: Fix broken DMA vs. MMIO ordering example")
> >
> > Signed-off-by: Parav Pandit <parav@xxxxxxxxxx>
> > ---
> > changelog:
> > v4->v5:
> > - Used suggested documentation update from Will
> > - Added comment to the writel() pseudo code example
> > - updated commit log for newer changes
>
> Sorry for the delay on this, I'm really behind on patches at the moment.
> This patch looks good to me, so thanks for doing it. You can either add
> my:
>
> Acked-by: Will Deacon <will@xxxxxxxxxx>
>
> or, since we worked on this together:
>
> Co-developed-by: Will Deacon <will@xxxxxxxxxx>
> Signed-off-by: Will Deacon <will@xxxxxxxxxx>

Thank you! I will apply these tags on the next rebase.

Thanx, Paul