diff mbox

[dpdk-dev,v2,1/8] eal: define container_of macro

Message ID 1479747322-5774-1-git-send-email-jblunck@infradead.org (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers

Checks

Context Check Description
checkpatch/checkpatch warning coding style issues

Commit Message

Jan Blunck Nov. 21, 2016, 4:55 p.m. UTC 
  This macro is based on Jan Viktorin's original patch but also checks the
type of the passed pointer against the type of the member.

Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
[jblunck@infradead.org: add type checking and __extension__]
Signed-off-by: Jan Blunck <jblunck@infradead.org>
---
 lib/librte_eal/common/include/rte_common.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Comments

Shreyansh Jain Nov. 22, 2016, 10:03 a.m. UTC | #1 
On Monday 21 November 2016 10:25 PM, Jan Blunck wrote:
> This macro is based on Jan Viktorin's original patch but also checks the
> type of the passed pointer against the type of the member.
>
> Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
> Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
> [jblunck@infradead.org: add type checking and __extension__]
> Signed-off-by: Jan Blunck <jblunck@infradead.org>
> ---
>  lib/librte_eal/common/include/rte_common.h | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>
> diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
> index db5ac91..8dda3e2 100644
> --- a/lib/librte_eal/common/include/rte_common.h
> +++ b/lib/librte_eal/common/include/rte_common.h
> @@ -331,6 +331,26 @@ rte_bsf32(uint32_t v)
>  #define offsetof(TYPE, MEMBER)  __builtin_offsetof (TYPE, MEMBER)
>  #endif
>
> +/**
> + * Return pointer to the wrapping struct instance.
> + *
> + * Example:
> + *
> + *  struct wrapper {
> + *      ...
> + *      struct child c;
> + *      ...
> + *  };
> + *
> + *  struct child *x = obtain(...);
> + *  struct wrapper *w = container_of(x, struct wrapper, c);
> + */
> +#ifndef container_of
> +#define container_of(ptr, type, member)	__extension__ ({		\
> +			typeof(((type *)0)->member) *_ptr = (ptr);	\
> +			(type *)(((char *)_ptr) - offsetof(type, member)); })
> +#endif
> +
>  #define _RTE_STR(x) #x
>  /** Take a macro value and get a string version of it */
>  #define RTE_STR(x) _RTE_STR(x)
>

I will start using this in my patchset.

Acked-by: Shreyansh Jain <shreyansh.jain@nxp.com>
Thomas Monjalon Nov. 22, 2016, 10:19 a.m. UTC | #2 
2016-11-22 15:33, Shreyansh Jain:
> On Monday 21 November 2016 10:25 PM, Jan Blunck wrote:
> > This macro is based on Jan Viktorin's original patch but also checks the
> > type of the passed pointer against the type of the member.
> >
> > Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
> > Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
> > [jblunck@infradead.org: add type checking and __extension__]
> > Signed-off-by: Jan Blunck <jblunck@infradead.org>
> 
> I will start using this in my patchset.
> 
> Acked-by: Shreyansh Jain <shreyansh.jain@nxp.com>

It is a bit strange to have this patch in a series which do
not use it. I am in favor of getting it when it is used
(and included) in another series.
Shreyansh Jain Nov. 22, 2016, 11:26 a.m. UTC | #3 
> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> Sent: Tuesday, November 22, 2016 3:50 PM
> To: Shreyansh Jain <shreyansh.jain@nxp.com>; Jan Blunck
> <jblunck@infradead.org>
> Cc: dev@dpdk.org; david.marchand@6wind.com; Jan Viktorin
> <viktorin@rehivetech.com>
> Subject: Re: [dpdk-dev] [PATCH v2 1/8] eal: define container_of macro
> 
> 2016-11-22 15:33, Shreyansh Jain:
> > On Monday 21 November 2016 10:25 PM, Jan Blunck wrote:
> > > This macro is based on Jan Viktorin's original patch but also checks the
> > > type of the passed pointer against the type of the member.
> > >
> > > Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
> > > Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
> > > [jblunck@infradead.org: add type checking and __extension__]
> > > Signed-off-by: Jan Blunck <jblunck@infradead.org>
> >
> > I will start using this in my patchset.
> >
> > Acked-by: Shreyansh Jain <shreyansh.jain@nxp.com>
> 
> It is a bit strange to have this patch in a series which do
> not use it. I am in favor of getting it when it is used
> (and included) in another series.

I can add this patch to my series, if Jan is ok about this.

-
Shreyansh
Jan Viktorin Nov. 22, 2016, 12:33 p.m. UTC | #4 
On Tue, 22 Nov 2016 11:26:50 +0000
Shreyansh Jain <shreyansh.jain@nxp.com> wrote:

> > -----Original Message-----
> > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > Sent: Tuesday, November 22, 2016 3:50 PM
> > To: Shreyansh Jain <shreyansh.jain@nxp.com>; Jan Blunck
> > <jblunck@infradead.org>
> > Cc: dev@dpdk.org; david.marchand@6wind.com; Jan Viktorin
> > <viktorin@rehivetech.com>
> > Subject: Re: [dpdk-dev] [PATCH v2 1/8] eal: define container_of macro
> > 
> > 2016-11-22 15:33, Shreyansh Jain:  
> > > On Monday 21 November 2016 10:25 PM, Jan Blunck wrote:  
> > > > This macro is based on Jan Viktorin's original patch but also checks the
> > > > type of the passed pointer against the type of the member.
> > > >
> > > > Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
> > > > Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
> > > > [jblunck@infradead.org: add type checking and __extension__]
> > > > Signed-off-by: Jan Blunck <jblunck@infradead.org>  
> > >
> > > I will start using this in my patchset.
> > >
> > > Acked-by: Shreyansh Jain <shreyansh.jain@nxp.com>  
> > 
> > It is a bit strange to have this patch in a series which do
> > not use it. I am in favor of getting it when it is used
> > (and included) in another series.  
> 
> I can add this patch to my series, if Jan is ok about this.

It's OK. Just merge it someday ;).

Jan

> 
> -
> Shreyansh
Shreyansh Jain Nov. 22, 2016, 12:36 p.m. UTC | #5 
> -----Original Message-----
> From: Jan Viktorin [mailto:viktorin@rehivetech.com]
> Sent: Tuesday, November 22, 2016 6:03 PM
> To: Shreyansh Jain <shreyansh.jain@nxp.com>
> Cc: Thomas Monjalon <thomas.monjalon@6wind.com>; Jan Blunck
> <jblunck@infradead.org>; dev@dpdk.org; david.marchand@6wind.com
> Subject: Re: [dpdk-dev] [PATCH v2 1/8] eal: define container_of macro
> 
> On Tue, 22 Nov 2016 11:26:50 +0000
> Shreyansh Jain <shreyansh.jain@nxp.com> wrote:
> 
> > > -----Original Message-----
> > > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > > Sent: Tuesday, November 22, 2016 3:50 PM
> > > To: Shreyansh Jain <shreyansh.jain@nxp.com>; Jan Blunck
> > > <jblunck@infradead.org>
> > > Cc: dev@dpdk.org; david.marchand@6wind.com; Jan Viktorin
> > > <viktorin@rehivetech.com>
> > > Subject: Re: [dpdk-dev] [PATCH v2 1/8] eal: define container_of macro
> > >
> > > 2016-11-22 15:33, Shreyansh Jain:
> > > > On Monday 21 November 2016 10:25 PM, Jan Blunck wrote:
> > > > > This macro is based on Jan Viktorin's original patch but also checks
> the
> > > > > type of the passed pointer against the type of the member.
> > > > >
> > > > > Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
> > > > > Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
> > > > > [jblunck@infradead.org: add type checking and __extension__]
> > > > > Signed-off-by: Jan Blunck <jblunck@infradead.org>
> > > >
> > > > I will start using this in my patchset.
> > > >
> > > > Acked-by: Shreyansh Jain <shreyansh.jain@nxp.com>
> > >
> > > It is a bit strange to have this patch in a series which do
> > > not use it. I am in favor of getting it when it is used
> > > (and included) in another series.
> >
> > I can add this patch to my series, if Jan is ok about this.
> 
> It's OK. Just merge it someday ;).

Actually, I meant Jan Blunck ;D
I have already been using your patch since long.

> 
> Jan
> 
> >
> > -
> > Shreyansh
> 
> 
> 
> --
>   Jan Viktorin                E-mail: Viktorin@RehiveTech.com
>   System Architect            Web:    www.RehiveTech.com
>   RehiveTech
>   Brno, Czech Republic
Shreyansh Jain Dec. 8, 2016, 7:01 a.m. UTC | #6 
Hello Jan,

Need your help in resolving the checkpatch issue for this patch.
I have used this in EAL Bus series [1].

[1] http://dpdk.org/ml/archives/dev/2016-December/051350.html

On Monday 21 November 2016 10:25 PM, Jan Blunck wrote:
> This macro is based on Jan Viktorin's original patch but also checks the
> type of the passed pointer against the type of the member.
>
> Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
> Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
> [jblunck@infradead.org: add type checking and __extension__]
> Signed-off-by: Jan Blunck <jblunck@infradead.org>
> ---
>  lib/librte_eal/common/include/rte_common.h | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>
> diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
> index db5ac91..8dda3e2 100644
> --- a/lib/librte_eal/common/include/rte_common.h
> +++ b/lib/librte_eal/common/include/rte_common.h
> @@ -331,6 +331,26 @@ rte_bsf32(uint32_t v)
>  #define offsetof(TYPE, MEMBER)  __builtin_offsetof (TYPE, MEMBER)
>  #endif
>
> +/**
> + * Return pointer to the wrapping struct instance.
> + *
> + * Example:
> + *
> + *  struct wrapper {
> + *      ...
> + *      struct child c;
> + *      ...
> + *  };
> + *
> + *  struct child *x = obtain(...);
> + *  struct wrapper *w = container_of(x, struct wrapper, c);
> + */
> +#ifndef container_of
> +#define container_of(ptr, type, member)	__extension__ ({		\
> +			typeof(((type *)0)->member) *_ptr = (ptr);	\
> +			(type *)(((char *)_ptr) - offsetof(type, member)); })
> +#endif

(I think there was discussion in ML about this but where, I couldn't 
find it).

Above code snippet doesn't go down well with the checkpatch script. It 
reports:

---->8----
ERROR:COMPLEX_MACRO: Macros with complex values should be enclosed in 
parentheses
#40: FILE: lib/librte_eal/common/include/rte_common.h:349:
+#define container_of(ptr, type, member)        __extension__ ({ 
        \
+                       typeof(((type *)0)->member) *_ptr = (ptr);      \
+                       (type *)(((char *)_ptr) - offsetof(type, 
member)); })

ERROR:SPACING: need consistent spacing around '*' (ctx:WxV)
#41: FILE: lib/librte_eal/common/include/rte_common.h:350:
+                       typeof(((type *)0)->member) *_ptr = (ptr);      \
---->8----

Second error is primarily because of '*<space>_ptr' rather than '*_ptr'.

Is do{ ... }while(0) the fix for the first one?

This:

---->8----
#ifndef container_of
#define container_of(ptr, type, member) do {                 \
            __extension__                                     \
            typeof(((type *)0)->member) * _ptr = (ptr);       \
            (type *)(((char *)_ptr) - offsetof(type, member));\
            } while (0)
#endif
---->8----

Seems to be ok with checkpatch. Do you see any technical/compiler issue 
with this?

> +
>  #define _RTE_STR(x) #x
>  /** Take a macro value and get a string version of it */
>  #define RTE_STR(x) _RTE_STR(x)
>

-
Shreyansh
Shreyansh Jain Dec. 9, 2016, 7:36 a.m. UTC | #7 
On Thursday 08 December 2016 12:31 PM, Shreyansh Jain wrote:
> Hello Jan,
>
> Need your help in resolving the checkpatch issue for this patch.
> I have used this in EAL Bus series [1].
>
> [1] http://dpdk.org/ml/archives/dev/2016-December/051350.html
>
> On Monday 21 November 2016 10:25 PM, Jan Blunck wrote:
>> This macro is based on Jan Viktorin's original patch but also checks the
>> type of the passed pointer against the type of the member.
>>
>> Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
>> Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
>> [jblunck@infradead.org: add type checking and __extension__]
>> Signed-off-by: Jan Blunck <jblunck@infradead.org>
>> ---
>>  lib/librte_eal/common/include/rte_common.h | 20 ++++++++++++++++++++
>>  1 file changed, 20 insertions(+)
>>
>> diff --git a/lib/librte_eal/common/include/rte_common.h
>> b/lib/librte_eal/common/include/rte_common.h
>> index db5ac91..8dda3e2 100644
>> --- a/lib/librte_eal/common/include/rte_common.h
>> +++ b/lib/librte_eal/common/include/rte_common.h
>> @@ -331,6 +331,26 @@ rte_bsf32(uint32_t v)
>>  #define offsetof(TYPE, MEMBER)  __builtin_offsetof (TYPE, MEMBER)
>>  #endif
>>
>> +/**
>> + * Return pointer to the wrapping struct instance.
>> + *
>> + * Example:
>> + *
>> + *  struct wrapper {
>> + *      ...
>> + *      struct child c;
>> + *      ...
>> + *  };
>> + *
>> + *  struct child *x = obtain(...);
>> + *  struct wrapper *w = container_of(x, struct wrapper, c);
>> + */
>> +#ifndef container_of
>> +#define container_of(ptr, type, member)    __extension__ ({        \
>> +            typeof(((type *)0)->member) *_ptr = (ptr);    \
>> +            (type *)(((char *)_ptr) - offsetof(type, member)); })
>> +#endif
>
> (I think there was discussion in ML about this but where, I couldn't
> find it).
>
> Above code snippet doesn't go down well with the checkpatch script. It
> reports:
>
> ---->8----
> ERROR:COMPLEX_MACRO: Macros with complex values should be enclosed in
> parentheses
> #40: FILE: lib/librte_eal/common/include/rte_common.h:349:
> +#define container_of(ptr, type, member)        __extension__ ({        \
> +                       typeof(((type *)0)->member) *_ptr = (ptr);      \
> +                       (type *)(((char *)_ptr) - offsetof(type,
> member)); })
>
> ERROR:SPACING: need consistent spacing around '*' (ctx:WxV)
> #41: FILE: lib/librte_eal/common/include/rte_common.h:350:
> +                       typeof(((type *)0)->member) *_ptr = (ptr);      \
> ---->8----
>
> Second error is primarily because of '*<space>_ptr' rather than '*_ptr'.
>
> Is do{ ... }while(0) the fix for the first one?
>
> This:
>
> ---->8----
> #ifndef container_of
> #define container_of(ptr, type, member) do {                 \
>            __extension__                                     \
>            typeof(((type *)0)->member) * _ptr = (ptr);       \
>            (type *)(((char *)_ptr) - offsetof(type, member));\
>            } while (0)
> #endif
> ---->8----
>
> Seems to be ok with checkpatch. Do you see any technical/compiler issue
> with this?

My bad.
obviously a 'do{ .. } while(0)' will not work in case of assignment.

Any other hints as to how to remove this checkpatch issue?

>
>> +
>>  #define _RTE_STR(x) #x
>>  /** Take a macro value and get a string version of it */
>>  #define RTE_STR(x) _RTE_STR(x)
>>
>
> -
> Shreyansh
>
>
>
diff mbox

Patch

diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
index db5ac91..8dda3e2 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -331,6 +331,26 @@  rte_bsf32(uint32_t v)
 #define offsetof(TYPE, MEMBER)  __builtin_offsetof (TYPE, MEMBER)
 #endif
 
+/**
+ * Return pointer to the wrapping struct instance.
+ *
+ * Example:
+ *
+ *  struct wrapper {
+ *      ...
+ *      struct child c;
+ *      ...
+ *  };
+ *
+ *  struct child *x = obtain(...);
+ *  struct wrapper *w = container_of(x, struct wrapper, c);
+ */
+#ifndef container_of
+#define container_of(ptr, type, member)	__extension__ ({		\
+			typeof(((type *)0)->member) *_ptr = (ptr);	\
+			(type *)(((char *)_ptr) - offsetof(type, member)); })
+#endif
+
 #define _RTE_STR(x) #x
 /** Take a macro value and get a string version of it */
 #define RTE_STR(x) _RTE_STR(x)