linux-kernel - [PATCH] fs/proc/vmcore.c: Put if tests in the top of the while loop to reduce duplication

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Message-ID: <510E6280.3070203@gmail.com>
Date:	Sun, 03 Feb 2013 21:13:36 +0800
From:	Zhang Yanfei <zhangyanfei.yes@...il.com>
To:	akpm@...ux-foundation.org
CC:	"Eric W. Biederman" <ebiederm@...ssion.com>,
	benh@...nel.crashing.org, mahesh@...ux.vnet.ibm.com,
	zhangyanfei@...fujitsu.com, linux-kernel@...r.kernel.org
Subject: [PATCH] fs/proc/vmcore.c: Put if tests in the top of the while loop
 to reduce duplication

From: Zhang Yanfei <zhangyanfei@...fujitsu.com>

In function read_vmcore, two if tests are duplicate. Change the position
of them could reduce the duplication. This change does not affect
the behaviour of the function.

Signed-off-by: Zhang Yanfei <zhangyanfei@...fujitsu.com>
---
 fs/proc/vmcore.c |   21 ++++++++-------------
 1 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 0d5071d..c74a901 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -175,15 +175,16 @@ static ssize_t read_vmcore(struct file *file, char __user *buffer,
 	start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
 	if (!curr_m)
         	return -EINVAL;
-	if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
-		tsz = buflen;
-
-	/* Calculate left bytes in current memory segment. */
-	nr_bytes = (curr_m->size - (start - curr_m->paddr));
-	if (tsz > nr_bytes)
-		tsz = nr_bytes;
 
 	while (buflen) {
+		if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
+			tsz = buflen;
+
+		/* Calculate left bytes in current memory segment. */
+		nr_bytes = (curr_m->size - (start - curr_m->paddr));
+		if (tsz > nr_bytes)
+			tsz = nr_bytes;
+
 		tmp = read_from_oldmem(buffer, tsz, &start, 1);
 		if (tmp < 0)
 			return tmp;
@@ -198,12 +199,6 @@ static ssize_t read_vmcore(struct file *file, char __user *buffer,
 						struct vmcore, list);
 			start = curr_m->paddr;
 		}
-		if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
-			tsz = buflen;
-		/* Calculate left bytes in current memory segment. */
-		nr_bytes = (curr_m->size - (start - curr_m->paddr));
-		if (tsz > nr_bytes)
-			tsz = nr_bytes;
 	}
 	return acc;
 }
-- 
1.7.1
--
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