From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o3FIFbDp183234 for ; Thu, 15 Apr 2010 13:15:37 -0500 Received: from cf--amer001e--3.americas.sgi.com (cf--amer001e--3.americas.sgi.com [137.38.100.5]) by relay1.corp.sgi.com (Postfix) with ESMTP id 448E38F80CA for ; Thu, 15 Apr 2010 11:17:31 -0700 (PDT) Subject: [PATCH 2/5] xfs: avoid repeated pointer dereferences From: Alex Elder Date: Thu, 15 Apr 2010 13:17:30 -0500 Message-ID: <1271355450.2680.91.camel@doink> Mime-Version: 1.0 Reply-To: aelder@sgi.com List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com In xlog_find_cycle_start() use a local variable for some repeated operations rather than constantly accessing the memory location whose address is passed in. (This version drops an assertion that a pointer is non-null.) Signed-off-by: Alex Elder --- fs/xfs/xfs_log_recover.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) Index: b/fs/xfs/xfs_log_recover.c =================================================================== --- a/fs/xfs/xfs_log_recover.c +++ b/fs/xfs/xfs_log_recover.c @@ -354,26 +354,27 @@ xlog_find_cycle_start( { xfs_caddr_t offset; xfs_daddr_t mid_blk; + xfs_daddr_t end_blk; uint mid_cycle; int error; - mid_blk = BLK_AVG(first_blk, *last_blk); - while (mid_blk != first_blk && mid_blk != *last_blk) { + end_blk = *last_blk; + mid_blk = BLK_AVG(first_blk, end_blk); + while (mid_blk != first_blk && mid_blk != end_blk) { error = xlog_bread(log, mid_blk, 1, bp, &offset); if (error) return error; mid_cycle = xlog_get_cycle(offset); - if (mid_cycle == cycle) { - *last_blk = mid_blk; - /* last_half_cycle == mid_cycle */ - } else { - first_blk = mid_blk; - /* first_half_cycle == mid_cycle */ - } - mid_blk = BLK_AVG(first_blk, *last_blk); + if (mid_cycle == cycle) + end_blk = mid_blk; /* last_half_cycle == mid_cycle */ + else + first_blk = mid_blk; /* first_half_cycle == mid_cycle */ + mid_blk = BLK_AVG(first_blk, end_blk); } - ASSERT((mid_blk == first_blk && mid_blk+1 == *last_blk) || - (mid_blk == *last_blk && mid_blk-1 == first_blk)); + ASSERT((mid_blk == first_blk && mid_blk+1 == end_blk) || + (mid_blk == end_blk && mid_blk-1 == first_blk)); + + *last_blk = end_blk; return 0; } _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs