[1/4] fs/ext3/balloc.c: delete useless initialization

Submitted by Julia Lawall on Aug. 4, 2011, 10:29 a.m.

Details

Message ID 1312453774-23333-2-git-send-email-julia@diku.dk
State Superseded, archived
Headers show

Commit Message

Julia Lawall Aug. 4, 2011, 10:29 a.m.
From: Julia Lawall <julia@diku.dk>

Delete nontrivial initialization that is immediately overwritten by the
result of an allocation function.

The semantic match that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
type T;
identifier i;
expression e;
@@

(
T i = \(0\|NULL\|ERR_PTR(...)\);
|
-T i = e;
+T i;
)
... when != i
i = \(kzalloc\|kcalloc\|kmalloc\)(...);

// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
 fs/ext3/balloc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)


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Comments

Jan Kara Aug. 4, 2011, 10:40 a.m.
On Thu 04-08-11 12:29:31, Julia Lawall wrote:
> From: Julia Lawall <julia@diku.dk>
> 
> Delete nontrivial initialization that is immediately overwritten by the
> result of an allocation function.
  Thanks. Merged.

								Honza

> 
> The semantic match that makes this change is as follows:
> (http://coccinelle.lip6.fr/)
> 
> // <smpl>
> @@
> type T;
> identifier i;
> expression e;
> @@
> 
> (
> T i = \(0\|NULL\|ERR_PTR(...)\);
> |
> -T i = e;
> +T i;
> )
> ... when != i
> i = \(kzalloc\|kcalloc\|kmalloc\)(...);
> 
> // </smpl>
> 
> Signed-off-by: Julia Lawall <julia@diku.dk>
> 
> ---
>  fs/ext3/balloc.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff -u -p a/fs/ext3/balloc.c b/fs/ext3/balloc.c
> --- a/fs/ext3/balloc.c
> +++ b/fs/ext3/balloc.c
> @@ -427,7 +427,7 @@ static inline int rsv_is_empty(struct ex
>  void ext3_init_block_alloc_info(struct inode *inode)
>  {
>  	struct ext3_inode_info *ei = EXT3_I(inode);
> -	struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info;
> +	struct ext3_block_alloc_info *block_i;
>  	struct super_block *sb = inode->i_sb;
>  
>  	block_i = kmalloc(sizeof(*block_i), GFP_NOFS);
>
Eric Sandeen Aug. 5, 2011, 5:24 p.m.
On 8/4/11 5:40 AM, Jan Kara wrote:
> On Thu 04-08-11 12:29:31, Julia Lawall wrote:
>> From: Julia Lawall <julia@diku.dk>
>>
>> Delete nontrivial initialization that is immediately overwritten by the
>> result of an allocation function.
>   Thanks. Merged.

Just FWIW, I was curious how this ended up here.

It looks like this has been there since 2005, and both
lines went in in the same commit (i.e. it didn't creep in over time).

http://git.kernel.org/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git;a=commitdiff;h=a66d457d8878fe8d09bc81f0d5e6ac40caec6eb7

-Eric

> 								Honza
> 
>>
>> The semantic match that makes this change is as follows:
>> (http://coccinelle.lip6.fr/)
>>
>> // <smpl>
>> @@
>> type T;
>> identifier i;
>> expression e;
>> @@
>>
>> (
>> T i = \(0\|NULL\|ERR_PTR(...)\);
>> |
>> -T i = e;
>> +T i;
>> )
>> ... when != i
>> i = \(kzalloc\|kcalloc\|kmalloc\)(...);
>>
>> // </smpl>
>>
>> Signed-off-by: Julia Lawall <julia@diku.dk>
>>
>> ---
>>  fs/ext3/balloc.c |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff -u -p a/fs/ext3/balloc.c b/fs/ext3/balloc.c
>> --- a/fs/ext3/balloc.c
>> +++ b/fs/ext3/balloc.c
>> @@ -427,7 +427,7 @@ static inline int rsv_is_empty(struct ex
>>  void ext3_init_block_alloc_info(struct inode *inode)
>>  {
>>  	struct ext3_inode_info *ei = EXT3_I(inode);
>> -	struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info;
>> +	struct ext3_block_alloc_info *block_i;
>>  	struct super_block *sb = inode->i_sb;
>>  
>>  	block_i = kmalloc(sizeof(*block_i), GFP_NOFS);
>>

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Julia Lawall Aug. 5, 2011, 7:08 p.m.
On Fri, 5 Aug 2011, Eric Sandeen wrote:

> On 8/4/11 5:40 AM, Jan Kara wrote:
> > On Thu 04-08-11 12:29:31, Julia Lawall wrote:
> >> From: Julia Lawall <julia@diku.dk>
> >>
> >> Delete nontrivial initialization that is immediately overwritten by the
> >> result of an allocation function.
> >   Thanks. Merged.
> 
> Just FWIW, I was curious how this ended up here.
> 
> It looks like this has been there since 2005, and both
> lines went in in the same commit (i.e. it didn't creep in over time).
> 
> http://git.kernel.org/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git;a=commitdiff;h=a66d457d8878fe8d09bc81f0d5e6ac40caec6eb7

Actually, the old code had the same property, for the rsv variable...

julia
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Patch hide | download patch | download mbox

diff -u -p a/fs/ext3/balloc.c b/fs/ext3/balloc.c
--- a/fs/ext3/balloc.c
+++ b/fs/ext3/balloc.c
@@ -427,7 +427,7 @@  static inline int rsv_is_empty(struct ex
 void ext3_init_block_alloc_info(struct inode *inode)
 {
 	struct ext3_inode_info *ei = EXT3_I(inode);
-	struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info;
+	struct ext3_block_alloc_info *block_i;
 	struct super_block *sb = inode->i_sb;
 
 	block_i = kmalloc(sizeof(*block_i), GFP_NOFS);