ext4: miscellaneous error checks and coding cleanups for mballoc

From: Shen Feng <shen@cn.fujitsu.com>

ext4_mb_seq_history_open(): check if sbi->s_mb_history is NULL

ext4_mb_history_init(): replace kmalloc and memset with kzalloc

ext4_mb_init_backend(): remove memset since kzalloc is used

ext4_mb_init(): the return value of ext4_mb_init_backend is int,
	but i is unsigned, replace it with a new int variable.

Signed-off-by: Shen Feng <shen@cn.fujitsu.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/ext4/mballoc.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

Index: linux-2.6.26-rc6/fs/ext4/mballoc.c
===================================================================
--- linux-2.6.26-rc6.orig/fs/ext4/mballoc.c	2008-06-17 10:43:25.000000000 -0700
+++ linux-2.6.26-rc6/fs/ext4/mballoc.c	2008-06-17 10:43:25.000000000 -0700
@@ -1979,6 +1979,8 @@ static int ext4_mb_seq_history_open(stru
 	int rc;
 	int size;
 
+	if (unlikely(sbi->s_mb_history == NULL))
+		return -ENOMEM;
 	s = kmalloc(sizeof(*s), GFP_KERNEL);
 	if (s == NULL)
 		return -ENOMEM;
@@ -2181,9 +2183,7 @@ static void ext4_mb_history_init(struct 
 	sbi->s_mb_history_cur = 0;
 	spin_lock_init(&sbi->s_mb_history_lock);
 	i = sbi->s_mb_history_max * sizeof(struct ext4_mb_history);
-	sbi->s_mb_history = kmalloc(i, GFP_KERNEL);
-	if (likely(sbi->s_mb_history != NULL))
-		memset(sbi->s_mb_history, 0, i);
+	sbi->s_mb_history = kzalloc(i, GFP_KERNEL);
 	/* if we can't allocate history, then we simple won't use it */
 }
 
@@ -2297,7 +2297,6 @@ static int ext4_mb_init_backend(struct s
 			i++;
 			goto err_freebuddy;
 		}
-		memset(meta_group_info[j], 0, len);
 		set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
 			&(meta_group_info[j]->bb_state));
 
@@ -2352,6 +2351,7 @@ int ext4_mb_init(struct super_block *sb,
 	unsigned i;
 	unsigned offset;
 	unsigned max;
+	int ret;
 
 	if (!test_opt(sb, MBALLOC))
 		return 0;
@@ -2386,12 +2386,12 @@ int ext4_mb_init(struct super_block *sb,
 	} while (i <= sb->s_blocksize_bits + 1);
 
 	/* init file for buddy data */
-	i = ext4_mb_init_backend(sb);
-	if (i) {
+	ret = ext4_mb_init_backend(sb);
+	if (ret != 0) {
 		clear_opt(sbi->s_mount_opt, MBALLOC);
 		kfree(sbi->s_mb_offsets);
 		kfree(sbi->s_mb_maxs);
-		return i;
+		return ret;
 	}
 
 	spin_lock_init(&sbi->s_md_lock);