From: Andrea Parri <andrea.parri@amarulasolutions.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
will.deacon@arm.com, aou@eecs.berkeley.edu, arnd@arndb.de,
bp@alien8.de, catalin.marinas@arm.com, davem@davemloft.net,
fenghua.yu@intel.com, heiko.carstens@de.ibm.com,
herbert@gondor.apana.org.au, ink@jurassic.park.msu.ru,
jhogan@kernel.org, linux@armlinux.org.uk, mattst88@gmail.com,
mingo@kernel.org, mpe@ellerman.id.au, palmer@sifive.com,
paul.burton@mips.com, paulus@samba.org, ralf@linux-mips.org,
rth@twiddle.net, stable@vger.kernel.org, tglx@linutronix.de,
tony.luck@intel.com, vgupta@synopsys.com
Subject: Re: [PATCH 00/18] locking/atomic: atomic64 type cleanup
Date: Thu, 23 May 2019 10:30:13 +0200 [thread overview]
Message-ID: <20190523083013.GA4616@andrea> (raw)
In-Reply-To: <20190522132250.26499-1-mark.rutland@arm.com>
Hi Mark,
On Wed, May 22, 2019 at 02:22:32PM +0100, Mark Rutland wrote:
> Currently architectures return inconsistent types for atomic64 ops. Some return
> long (e..g. powerpc), some return long long (e.g. arc), and some return s64
> (e.g. x86).
(only partially related, but probably worth asking:)
While reading the series, I realized that the following expression:
atomic64_t v;
...
typeof(v.counter) my_val = atomic64_set(&v, VAL);
is a valid expression on some architectures (in part., on architectures
which #define atomic64_set() to WRITE_ONCE()) but is invalid on others.
(This is due to the fact that WRITE_ONCE() can be used as an rvalue in
the above assignment; TBH, I ignore the reasons for having such rvalue?)
IIUC, similar considerations hold for atomic_set().
The question is whether this is a known/"expected" inconsistency in the
implementation of atomic64_set() or if this would also need to be fixed
/addressed (say in a different patchset)?
Thanks,
Andrea
next prev parent reply other threads:[~2019-05-23 8:30 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-22 13:22 [PATCH 00/18] locking/atomic: atomic64 type cleanup Mark Rutland
2019-05-22 13:22 ` [PATCH 01/18] locking/atomic: crypto: nx: prepare for atomic64_read() conversion Mark Rutland
2019-05-22 13:22 ` [PATCH 02/18] locking/atomic: s390/pci: " Mark Rutland
2019-05-22 13:22 ` [PATCH 03/18] locking/atomic: generic: use s64 for atomic64 Mark Rutland
2019-05-22 21:16 ` Arnd Bergmann
2019-05-22 13:22 ` [PATCH 04/18] locking/atomic: alpha: " Mark Rutland
2019-05-22 13:22 ` [PATCH 05/18] locking/atomic: arc: " Mark Rutland
2019-05-23 23:10 ` Vineet Gupta
2019-05-22 13:22 ` [PATCH 06/18] locking/atomic: arm: " Mark Rutland
2019-05-22 13:22 ` [PATCH 07/18] locking/atomic: arm64: " Mark Rutland
2019-05-22 13:22 ` [PATCH 08/18] locking/atomic: ia64: " Mark Rutland
2019-05-22 13:22 ` [PATCH 09/18] locking/atomic: mips: " Mark Rutland
2019-05-22 13:22 ` [PATCH 10/18] locking/atomic: powerpc: " Mark Rutland
2019-05-23 13:27 ` Michael Ellerman
2019-05-22 13:22 ` [PATCH 11/18] locking/atomic: riscv: fix atomic64_sub_if_positive() offset argument Mark Rutland
2019-05-22 19:06 ` Palmer Dabbelt
2019-05-22 13:22 ` [PATCH 12/18] locking/atomic: riscv: use s64 for atomic64 Mark Rutland
2019-05-22 19:06 ` Palmer Dabbelt
2019-05-23 10:23 ` Mark Rutland
2019-05-22 13:22 ` [PATCH 13/18] locking/atomic: s390: " Mark Rutland
2019-05-22 13:22 ` [PATCH 14/18] locking/atomic: sparc: " Mark Rutland
2019-05-22 13:22 ` [PATCH 15/18] locking/atomic: x86: " Mark Rutland
2019-05-22 13:22 ` [PATCH 16/18] locking/atomic: use s64 for atomic64_t on 64-bit Mark Rutland
2019-05-22 13:22 ` [PATCH 17/18] locking/atomic: crypto: nx: remove redundant casts Mark Rutland
2019-05-22 13:22 ` [PATCH 18/18] locking/atomic: s390/pci: " Mark Rutland
2019-05-22 21:18 ` [PATCH 00/18] locking/atomic: atomic64 type cleanup Arnd Bergmann
2019-05-23 10:28 ` Mark Rutland
2019-05-23 8:30 ` Andrea Parri [this message]
2019-05-23 10:19 ` Mark Rutland
2019-05-23 11:20 ` Andrea Parri
2019-05-24 10:37 ` Peter Zijlstra
2019-05-24 11:18 ` Peter Zijlstra
2019-05-24 11:38 ` Greg KH
2019-05-24 11:42 ` Will Deacon
2019-05-24 11:52 ` Peter Zijlstra
2019-05-24 22:43 ` Andrea Parri
2019-05-28 10:47 ` Peter Zijlstra
2019-05-28 11:15 ` Andrea Parri
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