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

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Submitter Julia Lawall
Date Aug. 4, 2011, 10:29 a.m.
Message ID <1312453774-23333-2-git-send-email-julia@diku.dk>
Download mbox | patch
Permalink /patch/108410/
State Superseded
Headers show

Comments

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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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

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);