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From: Xie XiuQi <xiexiuqi@huawei.com>
To: Jens Axboe <jens.axboe@oracle.com>, Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hanjun Guo <guohanjun@huawei.com>, Li Zefan <lizefan@huawei.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: [PATCH] smp: kill unnecessary variable - csd_flags
Date: Mon, 29 Jul 2013 10:29:45 +0800	[thread overview]
Message-ID: <51F5D399.3050609@huawei.com> (raw)

We used csd_flags formerly because we allocated csd_data by
kmalloc when "wait == 0". When fail to allocation, we will
fall back to on-stack allocation. "csd_data" might be invalid
after generic_exec_single return.

But now we use per cpu data for single cpu ipi calls, and
csd_data can't fall back to on-stack allocation when "wait == 0".

So csd_flags is unnecessary now. Remove it.

Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
---
 kernel/smp.c |   11 +----------
 1 files changed, 1 insertions(+), 10 deletions(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index 4dba0f7..cac2b6e 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -186,25 +186,16 @@ void generic_smp_call_function_single_interrupt(void)

 	while (!list_empty(&list)) {
 		struct call_single_data *csd;
-		unsigned int csd_flags;

 		csd = list_entry(list.next, struct call_single_data, list);
 		list_del(&csd->list);

-		/*
-		 * 'csd' can be invalid after this call if flags == 0
-		 * (when called through generic_exec_single()),
-		 * so save them away before making the call:
-		 */
-		csd_flags = csd->flags;
-
 		csd->func(csd->info);

 		/*
 		 * Unlocked CSDs are valid through generic_exec_single():
 		 */
-		if (csd_flags & CSD_FLAG_LOCK)
-			csd_unlock(csd);
+		csd_unlock(csd);
 	}
 }

-- 
1.6.0.2


             reply	other threads:[~2013-07-29  2:30 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-29  2:29 Xie XiuQi [this message]
2013-07-29 12:13 ` [PATCH] smp: kill unnecessary variable - csd_flags Peter Zijlstra
2013-07-30  1:46   ` Xie XiuQi

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