From: Ira Weiny <ira.weiny@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>,
x86@kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Fenghua Yu <fenghua.yu@intel.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH RFC V3 6/9] x86/entry: Pass irqentry_state_t by reference
Date: Tue, 20 Oct 2020 07:10:29 -0700 [thread overview]
Message-ID: <20201020141029.GE3713473@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <871rhtapir.fsf@nanos.tec.linutronix.de>
On Mon, Oct 19, 2020 at 11:12:44PM +0200, Thomas Gleixner wrote:
> On Mon, Oct 19 2020 at 13:26, Ira Weiny wrote:
> > On Mon, Oct 19, 2020 at 11:32:50AM +0200, Thomas Gleixner wrote:
> > Sorry, let me clarify. After this patch we have.
> >
> > typedef union irqentry_state {
> > bool exit_rcu;
> > bool lockdep;
> > } irqentry_state_t;
> >
> > Which reflects the mutual exclusion of the 2 variables.
>
> Huch? From the patch I gave you:
>
> #ifndef irqentry_state
> typedef struct irqentry_state {
> bool exit_rcu;
> + bool lockdep;
> } irqentry_state_t;
> #endif
>
> How is that a union?
I was proposing to make it a union.
>
> > But then when the pkrs stuff is added the union changes back to a structure and
> > looks like this.
>
> So you want:
>
> 1) Move stuff to struct irqentry_state (my patch)
>
> 2) Change it to a union and pass it as pointer at the same time
No, I would have made it a union in your patch.
Pass by reference would remain largely the same.
>
> 3) Change it back to struct to add PKRS
Yes. :-/
>
> > Is that clear?
>
> What's clear is that the above is nonsense. We can just do
>
> #ifndef irqentry_state
> typedef struct irqentry_state {
> union {
> bool exit_rcu;
> bool lockdep;
> };
> } irqentry_state_t;
> #endif
>
> right in the patch which I gave you. Because that actually makes sense.
Ok I'm very sorry. I was thinking that having a struct containing nothing but
an anonymous union would be unacceptable as a stand alone item in your patch.
In my experience other maintainers would have rejected such a change and
would have asked; 'why not just make it a union'?
I'm very happy skipping the gymnastics on individual patches in favor of making
the whole series work out in the end.
Thank you for your help again. :-)
Ira
next prev parent reply other threads:[~2020-10-20 14:10 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-09 19:42 [PATCH RFC V3 0/9] PKS: Add Protection Keys Supervisor (PKS) support RFC v3 ira.weiny
2020-10-09 19:42 ` [PATCH RFC V3 1/9] x86/pkeys: Create pkeys_common.h ira.weiny
2020-10-13 17:46 ` Dave Hansen
2020-10-13 19:44 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 2/9] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support ira.weiny
2020-10-13 17:50 ` Dave Hansen
2020-10-13 23:56 ` Ira Weiny
2020-10-16 10:57 ` Peter Zijlstra
2020-10-17 3:32 ` Ira Weiny
2020-10-19 9:35 ` Peter Zijlstra
2020-10-09 19:42 ` [PATCH RFC V3 3/9] x86/pks: Enable Protection Keys Supervisor (PKS) ira.weiny
2020-10-13 18:23 ` Dave Hansen
2020-10-14 2:08 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 4/9] x86/pks: Preserve the PKRS MSR on context switch ira.weiny
2020-10-13 18:31 ` Dave Hansen
2020-10-14 22:36 ` Ira Weiny
2020-10-16 11:12 ` Peter Zijlstra
2020-10-17 5:14 ` Ira Weiny
2020-10-19 9:37 ` Peter Zijlstra
2020-10-19 18:48 ` Ira Weiny
2020-10-16 11:06 ` Peter Zijlstra
2020-10-17 5:37 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 5/9] x86/pks: Add PKS kernel API ira.weiny
2020-10-13 18:43 ` Dave Hansen
2020-10-15 1:08 ` Ira Weiny
2020-10-16 11:07 ` Peter Zijlstra
2020-10-17 5:42 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 6/9] x86/entry: Pass irqentry_state_t by reference ira.weiny
2020-10-16 11:45 ` Peter Zijlstra
2020-10-16 12:55 ` Thomas Gleixner
2020-10-19 5:37 ` Ira Weiny
2020-10-19 9:32 ` Thomas Gleixner
2020-10-19 20:26 ` Ira Weiny
2020-10-19 21:12 ` Thomas Gleixner
2020-10-20 14:10 ` Ira Weiny [this message]
2020-10-09 19:42 ` [PATCH RFC V3 7/9] x86/entry: Preserve PKRS MSR across exceptions ira.weiny
2020-10-13 18:52 ` Dave Hansen
2020-10-15 3:46 ` Ira Weiny
2020-10-15 4:06 ` Dave Hansen
2020-10-15 4:18 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 8/9] x86/fault: Report the PKRS state on fault ira.weiny
2020-10-13 18:56 ` Dave Hansen
2020-10-15 4:13 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 9/9] x86/pks: Add PKS test code ira.weiny
2020-10-13 19:02 ` Dave Hansen
2020-10-15 4:46 ` Ira Weiny
2020-10-09 20:18 ` [PATCH RFC V3 0/9] PKS: Add Protection Keys Supervisor (PKS) support RFC v3 Ira Weiny
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