From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yuanhan Liu Subject: Re: [PATCH] md: remove redudent code Date: Tue, 15 May 2012 16:12:49 +0800 Message-ID: <20120515081249.GG10252@yliu-dev.sh.intel.com> References: <1337068825-11995-1-git-send-email-yuanhan.liu@linux.intel.com> <20120515180349.0f0d275e@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20120515180349.0f0d275e@notabene.brown> Sender: linux-kernel-owner@vger.kernel.org To: NeilBrown Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-raid.ids On Tue, May 15, 2012 at 06:03:49PM +1000, NeilBrown wrote: > On Tue, 15 May 2012 16:00:25 +0800 Yuanhan Liu > wrote: > > > The code does nothing but repating assigning sb->sb_csum with original > > value. > > This code sets the sb_csum to 0 while the csum is calculated. > > Without this, calculating the csum, setting it, then calculating again would > produce a different result. > > So the code is correct as is. Aha, got it. And sorry for the wrong patch. Thanks, Yuanhan Liu > > Thanks, > NeilBrown > > > > > > Signed-off-by: Yuanhan Liu > > --- > > drivers/md/md.c | 4 ---- > > 1 files changed, 0 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/md/md.c b/drivers/md/md.c > > index 0bd44e3..f2d799a 100644 > > --- a/drivers/md/md.c > > +++ b/drivers/md/md.c > > @@ -1439,15 +1439,12 @@ super_90_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors) > > > > static __le32 calc_sb_1_csum(struct mdp_superblock_1 * sb) > > { > > - __le32 disk_csum; > > u32 csum; > > unsigned long long newcsum; > > int size = 256 + le32_to_cpu(sb->max_dev)*2; > > __le32 *isuper = (__le32*)sb; > > int i; > > > > - disk_csum = sb->sb_csum; > > - sb->sb_csum = 0; > > newcsum = 0; > > for (i=0; size>=4; size -= 4 ) > > newcsum += le32_to_cpu(*isuper++); > > @@ -1456,7 +1453,6 @@ static __le32 calc_sb_1_csum(struct mdp_superblock_1 * sb) > > newcsum += le16_to_cpu(*(__le16*) isuper); > > > > csum = (newcsum & 0xffffffff) + (newcsum >> 32); > > - sb->sb_csum = disk_csum; > > return cpu_to_le32(csum); > > } > > >