linux-kernel - [PATCH] kernel: trace: blktrace: remove redundent memcpy() in compat_blk_trace

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Date:	Sun, 03 Nov 2013 22:23:39 +0800
From:	Chen Gang <gang.chen@...anux.com>
To:	Steven Rostedt <rostedt@...dmis.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Jens Axboe <axboe@...nel.dk>, Tejun Heo <tj@...nel.org>,
	Jan Kara <jack@...e.cz>
CC:	"mingo@...hat.com" <mingo@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH] kernel: trace: blktrace: remove redundent memcpy() in compat_blk_trace_setup()

do_blk_trace_setup() will fully initialize 'buts.name', so can remove
the related memcpy(). And also use BLKTRACE_BDEV_SIZE and ARRAY_SIZE
instead of hard code number '32'.


Signed-off-by: Chen Gang <gang.chen@...anux.com>
---
 include/linux/blktrace_api.h |    2 +-
 kernel/trace/blktrace.c      |    3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
index a12f6ed..afc1343 100644
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -89,7 +89,7 @@ static inline int blk_trace_init_sysfs(struct device *dev)
 #ifdef CONFIG_COMPAT
 
 struct compat_blk_user_trace_setup {
-	char name[32];
+	char name[BLKTRACE_BDEV_SIZE];
 	u16 act_mask;
 	u32 buf_size;
 	u32 buf_nr;
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 7f727b3..f785aef 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -579,13 +579,12 @@ static int compat_blk_trace_setup(struct request_queue *q, char *name,
 		.end_lba = cbuts.end_lba,
 		.pid = cbuts.pid,
 	};
-	memcpy(&buts.name, &cbuts.name, 32);
 
 	ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
 	if (ret)
 		return ret;
 
-	if (copy_to_user(arg, &buts.name, 32)) {
+	if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
 		blk_trace_remove(q);
 		return -EFAULT;
 	}
-- 
1.7.7.6
--
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