Re: [PATCH v2 1/4] mm/highmem: Fix kernel-doc warnings in highmem*.h

From: Fabio M. De Francesco
Date: Wed Apr 27 2022 - 01:28:22 EST

On martedì 26 aprile 2022 13:04:42 CEST Sebastian Andrzej Siewior wrote:
> On 2022-04-26 11:43:03 [+0200], Fabio M. De Francesco wrote:
> Either way, according to the code kmap_atomic() does not always disable
> preemption

Hi Sebastian,

In my last email (for patch 4/4) I wrote that I would add a deprecation
notice to kunmap_local() and would talk about thread locality in
kmap_local_page(). I want to confirm that I'll do these changes in v3.

Then I closed that email asking if I was still overlooking something.
Consider that I'm relatively new to kernel development and that it's just
something I do in my spare time. So I was pretty sure I was still missing
something :)

After reading again the code of kmap_atomic() (as you suggested - thanks!)
I noted that you correctly say that kmap_atomic() does not always disables
preemption (i.e., preemption is disabled only for !PREEMPT_RT kernel's

Therefore I'll also change the first sentence of kunmap_local() to the

"[It] Unmaps an address previously mapped by kmap_atomic() and re-enables
pagefaults and preemption (the latter disabled only for !PREEMP_RT

I will also be making this change in v3.

Can you please say if I'm still missing something?