[PATCH] Staging: erofs: Use !x in place of NULL comparision

[PATCH] Staging: erofs: Use !x in place of NULL comparision

[Bhanusree Pola]

Test for NULL as !x instead of NULL comparisions for
functions that return NULL on failure are used.
Issue found using coccinelle
Semantic patch used to solve the problem is as follows

// <smpl>
@@
expression x;
statement S;
@@

x = (\(kmalloc\|devm_kzalloc\|kmalloc_array\|devm_ioremap\|
usb_alloc_urb\|alloc_netdev\|dev_alloc_skb\)(...));

-if(x==NULL)
+if(!x)
// </smpl>

Signed-off-by: Bhanusree Pola <bhanusreemahesh@gmail.com>
---
 drivers/staging/erofs/xattr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/erofs/xattr.c b/drivers/staging/erofs/xattr.c
index f716ab0446e5..515b4b446491 100644
--- a/drivers/staging/erofs/xattr.c
+++ b/drivers/staging/erofs/xattr.c
@@ -107,7 +107,7 @@ static int init_inode_xattrs(struct inode *inode)
 	vi->xattr_shared_count = ih->h_shared_count;
 	vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
 						sizeof(uint), GFP_KERNEL);
-	if (vi->xattr_shared_xattrs == NULL) {
+	if (!vi->xattr_shared_xattrs) {
 		xattr_iter_end(&it, atomic_map);
 		ret = -ENOMEM;
 		goto out_unlock;
-- 
2.17.1

[PATCH] Staging: erofs: Use !x in place of NULL comparision

[Gao Xiang]

Hi Bhanusree,

On 2019/3/21 17:37, Bhanusree Pola wrote:
> Test for NULL as !x instead of NULL comparisions for
> functions that return NULL on failure are used.
> Issue found using coccinelle
> Semantic patch used to solve the problem is as follows
> 

My personal idea...There are still several other places which use
NULL comparisions introduced by the erofs original code, eg,
super.c
53:     if (vi == NULL)
90:     if (bh == NULL) {
...

internal.h
480:                    if (unlikely(bio == NULL)) {
488:    } while (unlikely(bio == NULL));
...

Could you have time fix them as much as possible in a patch?

It will simplify erofs commit log since there are similar
patches address the same reason but with few fixes...:

staging: erofs: unzip_vle.c: Replace comparison to NULL.
staging: erofs: Modify conditional checks
staging: erofs: formatting fix to NULL comparison

... Thanks in advance...

Thanks,
Gao Xiang

> // <smpl>
> @@
> expression x;
> statement S;
> @@
> 
> x = (\(kmalloc\|devm_kzalloc\|kmalloc_array\|devm_ioremap\|
> usb_alloc_urb\|alloc_netdev\|dev_alloc_skb\)(...));
> 
> -if(x==NULL)
> +if(!x)
> // </smpl>
> 
> Signed-off-by: Bhanusree Pola <bhanusreemahesh at gmail.com>
> ---
>  drivers/staging/erofs/xattr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/erofs/xattr.c b/drivers/staging/erofs/xattr.c
> index f716ab0446e5..515b4b446491 100644
> --- a/drivers/staging/erofs/xattr.c
> +++ b/drivers/staging/erofs/xattr.c
> @@ -107,7 +107,7 @@ static int init_inode_xattrs(struct inode *inode)
>  	vi->xattr_shared_count = ih->h_shared_count;
>  	vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
>  						sizeof(uint), GFP_KERNEL);
> -	if (vi->xattr_shared_xattrs == NULL) {
> +	if (!vi->xattr_shared_xattrs) {
>  		xattr_iter_end(&it, atomic_map);
>  		ret = -ENOMEM;
>  		goto out_unlock;
> 

Re: [PATCH] Staging: erofs: Use !x in place of NULL comparision

[Gao Xiang]

Hi Bhanusree,

On 2019/3/21 17:37, Bhanusree Pola wrote:
> Test for NULL as !x instead of NULL comparisions for
> functions that return NULL on failure are used.
> Issue found using coccinelle
> Semantic patch used to solve the problem is as follows
> 

My personal idea...There are still several other places which use
NULL comparisions introduced by the erofs original code, eg,
super.c
53:     if (vi == NULL)
90:     if (bh == NULL) {
...

internal.h
480:                    if (unlikely(bio == NULL)) {
488:    } while (unlikely(bio == NULL));
...

Could you have time fix them as much as possible in a patch?

It will simplify erofs commit log since there are similar
patches address the same reason but with few fixes...:

staging: erofs: unzip_vle.c: Replace comparison to NULL.
staging: erofs: Modify conditional checks
staging: erofs: formatting fix to NULL comparison

... Thanks in advance...

Thanks,
Gao Xiang

> // <smpl>
> @@
> expression x;
> statement S;
> @@
> 
> x = (\(kmalloc\|devm_kzalloc\|kmalloc_array\|devm_ioremap\|
> usb_alloc_urb\|alloc_netdev\|dev_alloc_skb\)(...));
> 
> -if(x==NULL)
> +if(!x)
> // </smpl>
> 
> Signed-off-by: Bhanusree Pola <bhanusreemahesh@gmail.com>
> ---
>  drivers/staging/erofs/xattr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/erofs/xattr.c b/drivers/staging/erofs/xattr.c
> index f716ab0446e5..515b4b446491 100644
> --- a/drivers/staging/erofs/xattr.c
> +++ b/drivers/staging/erofs/xattr.c
> @@ -107,7 +107,7 @@ static int init_inode_xattrs(struct inode *inode)
>  	vi->xattr_shared_count = ih->h_shared_count;
>  	vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
>  						sizeof(uint), GFP_KERNEL);
> -	if (vi->xattr_shared_xattrs == NULL) {
> +	if (!vi->xattr_shared_xattrs) {
>  		xattr_iter_end(&it, atomic_map);
>  		ret = -ENOMEM;
>  		goto out_unlock;
> 

[Outreachy kernel] Re: [PATCH] Staging: erofs: Use !x in place of NULL comparision

[Bhanusree Mahesh]

> On Mar 21, 2019,@15:42, Gao Xiang <gaoxiang25@huawei.com> wrote:
> 
> Hi Bhanusree,
> 
>> On 2019/3/21 17:37, Bhanusree Pola wrote:
>> Test for NULL as !x instead of NULL comparisions for
>> functions that return NULL on failure are used.
>> Issue found using coccinelle
>> Semantic patch used to solve the problem is as follows
>> 
> 
> My personal idea...There are still several other places which use
> NULL comparisions introduced by the erofs original code, eg,
> super.c
> 53:     if (vi == NULL)
> 90:     if (bh == NULL) {
> ...
> 
> internal.h
> 480:                    if (unlikely(bio == NULL)) {
> 488:    } while (unlikely(bio == NULL));
> ...
> 
> Could you have time fix them as much as possible in a patch?
> 
> It will simplify erofs commit log since there are similar
> patches address the same reason but with few fixes...:
> 
> staging: erofs: unzip_vle.c: Replace comparison to NULL.
> staging: erofs: Modify conditional checks
> staging: erofs: formatting fix to NULL comparison
> 
> ... Thanks in advance...

Sure!! I?ll do that and resend.

Bhanusree
> 
> Thanks,
> Gao Xiang
> 
>> // <smpl>
>> @@
>> expression x;
>> statement S;
>> @@
>> 
>> x = (\(kmalloc\|devm_kzalloc\|kmalloc_array\|devm_ioremap\|
>> usb_alloc_urb\|alloc_netdev\|dev_alloc_skb\)(...));
>> 
>> -if(x==NULL)
>> +if(!x)
>> // </smpl>
>> 
>> Signed-off-by: Bhanusree Pola <bhanusreemahesh at gmail.com>
>> ---
>> drivers/staging/erofs/xattr.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/staging/erofs/xattr.c b/drivers/staging/erofs/xattr.c
>> index f716ab0446e5..515b4b446491 100644
>> --- a/drivers/staging/erofs/xattr.c
>> +++ b/drivers/staging/erofs/xattr.c
>> @@ -107,7 +107,7 @@ static int init_inode_xattrs(struct inode *inode)
>>    vi->xattr_shared_count = ih->h_shared_count;
>>    vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
>>                        sizeof(uint), GFP_KERNEL);
>> -    if (vi->xattr_shared_xattrs == NULL) {
>> +    if (!vi->xattr_shared_xattrs) {
>>        xattr_iter_end(&it, atomic_map);
>>        ret = -ENOMEM;
>>        goto out_unlock;
>> 
> 
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Re: [Outreachy kernel] Re: [PATCH] Staging: erofs: Use !x in place of NULL comparision

[Bhanusree Mahesh]

> On Mar 21, 2019, at 15:42, Gao Xiang <gaoxiang25@huawei.com> wrote:
> 
> Hi Bhanusree,
> 
>> On 2019/3/21 17:37, Bhanusree Pola wrote:
>> Test for NULL as !x instead of NULL comparisions for
>> functions that return NULL on failure are used.
>> Issue found using coccinelle
>> Semantic patch used to solve the problem is as follows
>> 
> 
> My personal idea...There are still several other places which use
> NULL comparisions introduced by the erofs original code, eg,
> super.c
> 53:     if (vi == NULL)
> 90:     if (bh == NULL) {
> ...
> 
> internal.h
> 480:                    if (unlikely(bio == NULL)) {
> 488:    } while (unlikely(bio == NULL));
> ...
> 
> Could you have time fix them as much as possible in a patch?
> 
> It will simplify erofs commit log since there are similar
> patches address the same reason but with few fixes...:
> 
> staging: erofs: unzip_vle.c: Replace comparison to NULL.
> staging: erofs: Modify conditional checks
> staging: erofs: formatting fix to NULL comparison
> 
> ... Thanks in advance...

Sure!! I’ll do that and resend.

Bhanusree
> 
> Thanks,
> Gao Xiang
> 
>> // <smpl>
>> @@
>> expression x;
>> statement S;
>> @@
>> 
>> x = (\(kmalloc\|devm_kzalloc\|kmalloc_array\|devm_ioremap\|
>> usb_alloc_urb\|alloc_netdev\|dev_alloc_skb\)(...));
>> 
>> -if(x==NULL)
>> +if(!x)
>> // </smpl>
>> 
>> Signed-off-by: Bhanusree Pola <bhanusreemahesh@gmail.com>
>> ---
>> drivers/staging/erofs/xattr.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/staging/erofs/xattr.c b/drivers/staging/erofs/xattr.c
>> index f716ab0446e5..515b4b446491 100644
>> --- a/drivers/staging/erofs/xattr.c
>> +++ b/drivers/staging/erofs/xattr.c
>> @@ -107,7 +107,7 @@ static int init_inode_xattrs(struct inode *inode)
>>    vi->xattr_shared_count = ih->h_shared_count;
>>    vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
>>                        sizeof(uint), GFP_KERNEL);
>> -    if (vi->xattr_shared_xattrs == NULL) {
>> +    if (!vi->xattr_shared_xattrs) {
>>        xattr_iter_end(&it, atomic_map);
>>        ret = -ENOMEM;
>>        goto out_unlock;
>> 
> 
> -- 
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> To view this discussion on the web visit https://groups.google.com/d/msgid/outreachy-kernel/0a20b616-b2b9-9e38-3c0c-c8860cc41a0c%40huawei.com.
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