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From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] locking/qspinlock: Fix build for anonymous union in older gcc compilers
Date: Fri, 22 Jun 2018 08:49:20 +0100	[thread overview]
Message-ID: <20180622074920.GA7601@arm.com> (raw)
In-Reply-To: <20180621203526.172ab5c4@vmware.local.home>

Hi Steve,

On Thu, Jun 21, 2018 at 08:35:26PM -0400, 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>
> ---

Cheers for spotting this and fixing it up! I know it's already in -tip, but
anyway:

Acked-by: Will Deacon <will.deacon@arm.com>

Will

WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will.deacon@arm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Waiman Long <longman@redhat.com>,
	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 08:49:20 +0100	[thread overview]
Message-ID: <20180622074920.GA7601@arm.com> (raw)
In-Reply-To: <20180621203526.172ab5c4@vmware.local.home>

Hi Steve,

On Thu, Jun 21, 2018 at 08:35:26PM -0400, 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>
> ---

Cheers for spotting this and fixing it up! I know it's already in -tip, but
anyway:

Acked-by: Will Deacon <will.deacon@arm.com>

Will

  parent reply	other threads:[~2018-06-22  7:49 UTC|newest]

Thread overview: 7+ 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  0:35 ` Steven Rostedt
2018-06-22  2:05 ` Waiman Long
2018-06-22  2:05   ` Waiman Long
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 ` Will Deacon [this message]
2018-06-22  7:49   ` [PATCH] locking/qspinlock: Fix build for anonymous union in older gcc compilers Will Deacon

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