From: Thomas Gleixner <tglx@linutronix.de>
To: Herbert Xu <herbert@gondor.apana.org.au>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ard Biesheuvel <ardb@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux Crypto Mailing List <linux-crypto@vger.kernel.org>
Subject: Re: [PATCH] crypto: lib/chacha20poly1305 - Set SG_MITER_ATOMIC unconditionally
Date: Tue, 15 Sep 2020 11:34:14 +0200 [thread overview]
Message-ID: <878sdb5qp5.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20200915070523.GA26629@gondor.apana.org.au>
On Tue, Sep 15 2020 at 17:05, Herbert Xu wrote:
> On Mon, Sep 14, 2020 at 11:55:53PM -0700, Linus Torvalds wrote:
>>
>> Maybe we could hide it behind a debug option, at least.
>>
>> Or, alterantively, introduce a new "debug_preempt_count" that doesn't
>> actually disable preemption, but warns about actual sleeping
>> operations..
>
> I'm more worried about existing users of kmap_atomic relying on
> the preemption disabling semantics. Short of someone checking
> on every single instance (and that would include derived cases
> such as all users of sg miter), I think the safer option is to
> create something brand new and then migrate the existing users
> to it. Something like
>
> static inline void *kmap_atomic_ifhigh(struct page *page)
> {
> if (PageHighMem(page))
> return kmap_atomic(page);
> return page_address(page);
> }
>
> static inline void kunmap_atomic_ifhigh(struct page *page, void *addr)
> {
> if (PageHighMem(page))
> kunmap_atomic(addr);
> }
Hmm, that still has the issue that the code between map and unmap must
not sleep and the conversion must carefully check whether anything in
this region relies on preemption being disabled by kmap_atomic()
regardless of highmem or not.
kmap_atomic() is at least consistent vs. preemption, the above not so
much.
I'd rather go for a preemptible/sleepable version of highmem mapping
which is in itself consistent for both highmen and not highmem.
Thanks,
tglx
next prev parent reply other threads:[~2020-09-15 9:34 UTC|newest]
Thread overview: 282+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-14 20:42 [patch 00/13] preempt: Make preempt count unconditional Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [patch 01/13] lib/debug: Remove pointless ARCH_NO_PREEMPT dependencies Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [patch 02/13] preempt: Make preempt count unconditional Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [patch 03/13] preempt: Clenaup PREEMPT_COUNT leftovers Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-16 10:56 ` Valentin Schneider
2020-09-16 10:56 ` Valentin Schneider
2020-09-16 10:56 ` [Intel-gfx] " Valentin Schneider
2020-09-16 10:56 ` Valentin Schneider
2020-09-14 20:42 ` [patch 04/13] lockdep: " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-15 16:11 ` Will Deacon
2020-09-15 16:11 ` Will Deacon
2020-09-15 16:11 ` [Intel-gfx] " Will Deacon
2020-09-15 16:11 ` Will Deacon
2020-09-15 16:11 ` Will Deacon
2020-09-14 20:42 ` [patch 05/13] mm/pagemap: " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-15 0:52 ` kernel test robot
2020-09-15 0:52 ` kernel test robot
2020-09-15 2:40 ` kernel test robot
2020-09-15 5:28 ` kernel test robot
2020-09-14 20:42 ` [patch 06/13] locking/bitspinlock: " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-15 16:10 ` Will Deacon
2020-09-15 16:10 ` Will Deacon
2020-09-15 16:10 ` [Intel-gfx] " Will Deacon
2020-09-15 16:10 ` Will Deacon
2020-09-15 16:10 ` Will Deacon
2020-09-14 20:42 ` [patch 07/13] uaccess: " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [patch 08/13] sched: " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-16 10:56 ` Valentin Schneider
2020-09-16 10:56 ` Valentin Schneider
2020-09-16 10:56 ` [Intel-gfx] " Valentin Schneider
2020-09-16 10:56 ` Valentin Schneider
2020-09-14 20:42 ` [patch 09/13] ARM: " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [patch 10/13] xtensa: " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [patch 11/13] drm/i915: " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [patch 12/13] rcutorture: " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [patch 13/13] preempt: Remove PREEMPT_COUNT from Kconfig Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:42 ` Thomas Gleixner
2020-09-14 20:54 ` [patch 00/13] preempt: Make preempt count unconditional Steven Rostedt
2020-09-14 20:54 ` Steven Rostedt
2020-09-14 20:54 ` [Intel-gfx] " Steven Rostedt
2020-09-14 20:54 ` Steven Rostedt
2020-09-14 20:54 ` Steven Rostedt
2020-09-14 20:59 ` Linus Torvalds
2020-09-14 20:59 ` Linus Torvalds
2020-09-14 20:59 ` [Intel-gfx] " Linus Torvalds
2020-09-14 20:59 ` Linus Torvalds
2020-09-14 20:59 ` Linus Torvalds
2020-09-14 21:55 ` Thomas Gleixner
2020-09-14 21:55 ` Thomas Gleixner
2020-09-14 21:55 ` Thomas Gleixner
2020-09-14 21:55 ` [Intel-gfx] " Thomas Gleixner
2020-09-14 21:55 ` Thomas Gleixner
2020-09-14 21:55 ` Thomas Gleixner
2020-09-14 22:24 ` Linus Torvalds
2020-09-14 22:24 ` Linus Torvalds
2020-09-14 22:24 ` [Intel-gfx] " Linus Torvalds
2020-09-14 22:24 ` Linus Torvalds
2020-09-14 22:37 ` Linus Torvalds
2020-09-14 22:37 ` Linus Torvalds
2020-09-14 22:37 ` [Intel-gfx] " Linus Torvalds
2020-09-14 22:37 ` Linus Torvalds
2020-09-15 3:21 ` [PATCH] crypto: lib/chacha20poly1305 - Set SG_MITER_ATOMIC unconditionally Herbert Xu
2020-09-15 3:21 ` Herbert Xu
2020-09-15 3:21 ` Herbert Xu
2020-09-15 3:21 ` [Intel-gfx] " Herbert Xu
2020-09-15 3:21 ` Herbert Xu
2020-09-15 3:30 ` Herbert Xu
2020-09-15 6:03 ` Ard Biesheuvel
2020-09-15 6:40 ` Herbert Xu
2020-09-15 6:45 ` Linus Torvalds
2020-09-15 6:55 ` Linus Torvalds
2020-09-15 7:05 ` Herbert Xu
2020-09-15 7:10 ` Ard Biesheuvel
2020-09-15 9:34 ` Thomas Gleixner [this message]
2020-09-15 10:02 ` Ard Biesheuvel
2020-09-15 10:05 ` Herbert Xu
2020-09-15 10:08 ` Ard Biesheuvel
2020-09-15 10:10 ` Herbert Xu
2020-09-15 19:04 ` Thomas Gleixner
2020-09-15 7:08 ` Ard Biesheuvel
2020-09-15 6:20 ` [patch 00/13] preempt: Make preempt count unconditional Ard Biesheuvel
2020-09-15 6:20 ` Ard Biesheuvel
2020-09-15 6:20 ` [Intel-gfx] " Ard Biesheuvel
2020-09-15 6:20 ` Ard Biesheuvel
2020-09-15 6:20 ` Ard Biesheuvel
2020-09-15 6:22 ` Herbert Xu
2020-09-15 6:22 ` Herbert Xu
2020-09-15 6:22 ` Herbert Xu
2020-09-15 6:22 ` [Intel-gfx] " Herbert Xu
2020-09-15 6:22 ` Herbert Xu
2020-09-15 6:39 ` Linus Torvalds
2020-09-15 6:39 ` Linus Torvalds
2020-09-15 6:39 ` [Intel-gfx] " Linus Torvalds
2020-09-15 6:39 ` Linus Torvalds
2020-09-15 6:39 ` Linus Torvalds
2020-09-15 7:24 ` Thomas Gleixner
2020-09-15 7:24 ` Thomas Gleixner
2020-09-15 7:24 ` [Intel-gfx] " Thomas Gleixner
2020-09-15 17:29 ` Linus Torvalds
2020-09-15 17:29 ` Linus Torvalds
2020-09-15 17:29 ` [Intel-gfx] " Linus Torvalds
2020-09-15 17:29 ` Linus Torvalds
2020-09-15 17:29 ` Linus Torvalds
2020-09-15 8:39 ` Thomas Gleixner
2020-09-15 8:39 ` Thomas Gleixner
2020-09-15 8:39 ` Thomas Gleixner
2020-09-15 8:39 ` [Intel-gfx] " Thomas Gleixner
2020-09-15 8:39 ` Thomas Gleixner
2020-09-15 17:35 ` Linus Torvalds
2020-09-15 17:35 ` Linus Torvalds
2020-09-15 17:35 ` [Intel-gfx] " Linus Torvalds
2020-09-15 17:35 ` Linus Torvalds
2020-09-15 17:35 ` Linus Torvalds
2020-09-15 19:57 ` Thomas Gleixner
2020-09-15 19:57 ` Thomas Gleixner
2020-09-15 19:57 ` Thomas Gleixner
2020-09-15 19:57 ` [Intel-gfx] " Thomas Gleixner
2020-09-15 19:57 ` Thomas Gleixner
2020-09-15 19:57 ` Thomas Gleixner
2020-09-16 18:34 ` Linus Torvalds
2020-09-16 18:34 ` Linus Torvalds
2020-09-16 18:34 ` [Intel-gfx] " Linus Torvalds
2020-09-16 18:34 ` Linus Torvalds
2020-09-16 18:34 ` Linus Torvalds
2020-09-16 7:37 ` Daniel Vetter
2020-09-16 7:37 ` Daniel Vetter
2020-09-16 7:37 ` [Intel-gfx] " Daniel Vetter
2020-09-16 7:37 ` Daniel Vetter
2020-09-16 7:37 ` Daniel Vetter
2020-09-16 15:29 ` Paul E. McKenney
2020-09-16 15:29 ` Paul E. McKenney
2020-09-16 15:29 ` [Intel-gfx] " Paul E. McKenney
2020-09-16 15:29 ` Paul E. McKenney
2020-09-16 15:29 ` Paul E. McKenney
2020-09-16 18:32 ` Linus Torvalds
2020-09-16 18:32 ` Linus Torvalds
2020-09-16 18:32 ` [Intel-gfx] " Linus Torvalds
2020-09-16 18:32 ` Linus Torvalds
2020-09-16 18:32 ` Linus Torvalds
2020-09-16 20:43 ` Paul E. McKenney
2020-09-16 20:43 ` Paul E. McKenney
2020-09-16 20:43 ` [Intel-gfx] " Paul E. McKenney
2020-09-16 20:43 ` Paul E. McKenney
2020-09-16 20:43 ` Paul E. McKenney
2020-09-17 6:38 ` Ard Biesheuvel
2020-09-17 6:38 ` Ard Biesheuvel
2020-09-17 6:38 ` [Intel-gfx] " Ard Biesheuvel
2020-09-17 6:38 ` Ard Biesheuvel
2020-09-17 6:38 ` Ard Biesheuvel
2020-09-16 20:29 ` Daniel Vetter
2020-09-16 20:29 ` Daniel Vetter
2020-09-16 20:29 ` [Intel-gfx] " Daniel Vetter
2020-09-16 20:29 ` Daniel Vetter
2020-09-16 20:29 ` Daniel Vetter
2020-09-16 20:58 ` Paul E. McKenney
2020-09-16 20:58 ` Paul E. McKenney
2020-09-16 20:58 ` [Intel-gfx] " Paul E. McKenney
2020-09-16 20:58 ` Paul E. McKenney
2020-09-16 20:58 ` Paul E. McKenney
2020-09-16 21:43 ` Daniel Vetter
2020-09-16 21:43 ` Daniel Vetter
2020-09-16 21:43 ` [Intel-gfx] " Daniel Vetter
2020-09-16 21:43 ` Daniel Vetter
2020-09-16 21:43 ` Daniel Vetter
2020-09-16 22:39 ` Paul E. McKenney
2020-09-16 22:39 ` Paul E. McKenney
2020-09-16 22:39 ` [Intel-gfx] " Paul E. McKenney
2020-09-16 22:39 ` Paul E. McKenney
2020-09-16 22:39 ` Paul E. McKenney
2020-09-17 7:52 ` Daniel Vetter
2020-09-17 7:52 ` Daniel Vetter
2020-09-17 7:52 ` [Intel-gfx] " Daniel Vetter
2020-09-17 7:52 ` Daniel Vetter
2020-09-17 7:52 ` Daniel Vetter
2020-09-17 16:28 ` Paul E. McKenney
2020-09-17 16:28 ` Paul E. McKenney
2020-09-17 16:28 ` [Intel-gfx] " Paul E. McKenney
2020-09-17 16:28 ` Paul E. McKenney
2020-09-17 16:28 ` Paul E. McKenney
2020-09-29 8:19 ` Michal Hocko
2020-09-29 8:23 ` [Intel-gfx] " Michal Hocko
2020-09-29 8:23 ` Michal Hocko
2020-09-29 8:23 ` Michal Hocko
2020-09-29 8:23 ` Michal Hocko
2020-09-29 8:21 ` [Intel-gfx] " Michal Hocko
2020-09-29 8:21 ` Michal Hocko
2020-09-29 8:21 ` Michal Hocko
2020-09-29 8:21 ` Michal Hocko
2020-09-29 8:20 ` [Intel-gfx] " Michal Hocko
2020-09-29 8:20 ` Michal Hocko
2020-09-29 8:20 ` Michal Hocko
2020-09-29 8:20 ` Michal Hocko
2020-09-29 8:19 ` [Intel-gfx] " Michal Hocko
2020-09-29 8:19 ` Michal Hocko
2020-09-29 8:19 ` Michal Hocko
2020-09-29 8:19 ` Michal Hocko
2020-09-29 8:19 ` Michal Hocko
2020-09-29 8:19 ` [Intel-gfx] " Michal Hocko
2020-09-29 8:19 ` Michal Hocko
2020-09-29 8:19 ` Michal Hocko
2020-09-29 9:00 ` Daniel Vetter
2020-09-29 9:00 ` Daniel Vetter
2020-09-29 9:00 ` [Intel-gfx] " Daniel Vetter
2020-09-29 9:00 ` Daniel Vetter
2020-09-29 9:00 ` Daniel Vetter
2020-09-29 14:54 ` Michal Hocko
2020-09-29 14:54 ` Michal Hocko
2020-09-29 14:54 ` [Intel-gfx] " Michal Hocko
2020-09-29 14:54 ` Michal Hocko
2020-09-29 14:54 ` Michal Hocko
2020-09-16 19:23 ` Matthew Wilcox
2020-09-16 19:23 ` Matthew Wilcox
2020-09-16 19:23 ` [Intel-gfx] " Matthew Wilcox
2020-09-16 19:23 ` Matthew Wilcox
2020-09-16 19:23 ` Matthew Wilcox
2020-09-16 20:48 ` Paul E. McKenney
2020-09-16 20:48 ` Paul E. McKenney
2020-09-16 20:48 ` [Intel-gfx] " Paul E. McKenney
2020-09-16 20:48 ` Paul E. McKenney
2020-09-16 20:48 ` Paul E. McKenney
2020-09-15 17:25 ` Paul E. McKenney
2020-09-15 17:25 ` Paul E. McKenney
2020-09-15 17:25 ` [Intel-gfx] " Paul E. McKenney
2020-09-15 17:25 ` Paul E. McKenney
2020-09-15 17:25 ` Paul E. McKenney
2020-09-15 17:25 ` Paul E. McKenney
2020-09-14 22:01 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for " Patchwork
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