From: Waiman Long <longman@redhat.com>
To: Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Will Deacon <will.deacon@arm.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Boqun Feng <boqun.feng@gmail.com>, Ingo Molnar <mingo@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] locking/qspinlock: Fix build for anonymous union in older gcc compilers
Date: Fri, 22 Jun 2018 10:05:08 +0800 [thread overview]
Message-ID: <173298ff-4b5a-4f86-4f86-42287676e9ad@redhat.com> (raw)
In-Reply-To: <20180621203526.172ab5c4@vmware.local.home>
On 06/22/2018 08:35 AM, Steven Rostedt wrote:
> From: Steven Rostedt (VMware) <rostedt@goodmis.org>
>
> One of my tests compiles the kernel with gcc 4.5.3, and I hit the
> following build error:
>
> /work/git/linux-trace.git/include/linux/semaphore.h: In function 'sema_init':
> /work/git/linux-trace.git/include/linux/semaphore.h:35:17: error: unknown field 'val' specified in initializer
> /work/git/linux-trace.git/include/linux/semaphore.h:35:17: warning: missing braces around initializer
> /work/git/linux-trace.git/include/linux/semaphore.h:35:17: warning: (near initialization for '(anonymous).raw_lock.<anonymous>.val')
> In file included from /work/git/linux-trace.git/include/linux/sched/user.h:7:0,
> from /work/git/linux-trace.git/include/linux/cred.h:22,
> from /work/git/linux-trace.git/include/linux/seq_file.h:12,
> from /work/git/linux-trace.git/include/linux/cgroup.h:18,
> from /work/git/linux-trace.git/include/linux/memcontrol.h:22,
> from /work/git/linux-trace.git/include/linux/swap.h:9,
> from /work/git/linux-trace.git/include/linux/suspend.h:5,
> from /work/git/linux-trace.git/arch/x86/kernel/asm-offsets.c:13:
>
>
> I bisected it down to the introduction of the commit that makes
> qspinlock have an anonymous union, which makes initializing it special
> for older compilers. By adding strategic brackets, it makes the build
> happy again.
>
> Fixes: 625e88be1f41 ("locking/qspinlock: Merge 'struct __qspinlock' into 'struct qspinlock'")
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
> diff --git a/include/asm-generic/qspinlock_types.h b/include/asm-generic/qspinlock_types.h
> index 0763f065b975..d10f1e7d6ba8 100644
> --- a/include/asm-generic/qspinlock_types.h
> +++ b/include/asm-generic/qspinlock_types.h
> @@ -63,7 +63,7 @@ typedef struct qspinlock {
> /*
> * Initializier
> */
> -#define __ARCH_SPIN_LOCK_UNLOCKED { .val = ATOMIC_INIT(0) }
> +#define __ARCH_SPIN_LOCK_UNLOCKED { { .val = ATOMIC_INIT(0) } }
>
> /*
> * Bitfields in the atomic value:
Acked-by: Waiman Long <longman@redhat.com>
next prev parent reply other threads:[~2018-06-22 2:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-22 0:35 [PATCH] locking/qspinlock: Fix build for anonymous union in older gcc compilers Steven Rostedt
2018-06-22 2:05 ` Waiman Long [this message]
2018-06-22 2:24 ` [tip:locking/urgent] locking/qspinlock: Fix build for anonymous union in older GCC compilers tip-bot for Steven Rostedt (VMware)
2018-06-22 7:49 ` [PATCH] locking/qspinlock: Fix build for anonymous union in older gcc compilers Will Deacon
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