linux-kernel - Re: [PATCH v4 1/1] mm/highmem: Remove deprecated kmap

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Date:   Mon, 8 Nov 2021 15:42:59 +0530
From:   Prathu Baronia <prathubaronia2011@...il.com>
To:     Ira Weiny <ira.weiny@...el.com>
Cc:     Matthew Wilcox <willy@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, chintan.pandya@...plus.com,
        Prathu Baronia <prathu.baronia@...plus.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Randy Dunlap <rdunlap@...radead.org>
Subject: Re: [PATCH v4 1/1] mm/highmem: Remove deprecated kmap_atomic

Hi Mathew,
Sorry for the late reply, I was on vacation. I can see that you
already fixed up the patch(added the zero_user_segments part) and the
patch[1] is now merged in the mainline. Thanks for fixing it up. Also
for the memset_page() thing, IIUC would the below diff suffice?

diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 25aff0f2ed0b..dfe21e6a696b 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -332,6 +332,7 @@ static inline void memset_page(struct page *page,
size_t offset, int val,

     VM_BUG_ON(offset + len > PAGE_SIZE);
     memset(addr + offset, val, len);
+    flush_dcache_page(page);
     kunmap_local(addr);
 }


- Prathu

[1]: https://github.com/torvalds/linux/commit/d2c20e51e3966bc668ef1ef21fbe90704286c8d0#diff-a5b54499adfa477c1341f1d74cb5331481f00ff9afb4c8d600be19e2d8fa7e30

On Sat, Nov 6, 2021 at 12:08 AM Ira Weiny <ira.weiny@...el.com> wrote:
>
> On Fri, Nov 05, 2021 at 05:23:11PM +0000, Matthew Wilcox wrote:
> > On Fri, Nov 05, 2021 at 09:58:59AM -0700, Ira Weiny wrote:
> > > On Fri, Nov 05, 2021 at 04:51:40PM +0000, Matthew Wilcox wrote:
> > > > On Fri, Nov 05, 2021 at 01:50:37PM +0000, Matthew Wilcox wrote:
> > > > > On Thu, Feb 11, 2021 at 03:56:25PM -0800, Andrew Morton wrote:
> > > > > > On Wed, 10 Feb 2021 16:33:07 -0800 Ira Weiny <ira.weiny@...el.com> wrote:
> > > > > >
> > > > > > > > Signed-off-by: Ira Weiny <ira.weiny@...el.com>
> > > > > > >
> > > > > > > This already has my signed off by so I'm not going to 'review'.  With Prathu's
> > > > > > > testing information I hope this can land.
> > > > > > >
> > > > > > > Andrew did you see this patch?
> > > > > >
> > > > > > I did now ;)
> > > > > >
> > > > > > Tossed onto the post-rc1 pile, thanks,
> > > > >
> > > > > This patch seems to have slipped through the gaps for a couple of cycles
> > > > > now?  I found a missed spot in it for CONFIG_HIGHMEM:
> > > >
> > > > Ugh, sorry, wrong version of the patch.
> > >
> > > Check!  Yea this works for me...
> > >
> > > I think this should to through as a separate patch because Prathu's has been
> > > soaking for some time.  No need to complicate it with this.
> >
> > This isn't "complicating Prathu's patch".  This is "fixing up the bit
> > that Prathu missed with his patch".  zero_user_segments() should not
> > have different rules on HIGHMEM and non-HIGHMEM kernels.
>
> What do you mean by 'different rules'?
>
> Oh I see...  Ok yea.
>
> Well this should not be a big deal...
>
> Ira