Re: [PATCH] tools/virtio: fix build caused by virtio_ring changes

[Shunsuke Mie <mie@igel.co.jp>]

On 2023/04/10 19:58, Michael S. Tsirkin wrote:
> On Mon, Apr 10, 2023 at 07:56:13PM +0900, Shunsuke Mie wrote:
>> On 2023/04/10 19:00, Shunsuke Mie wrote:
>>> On 2023/04/10 18:46, Michael S. Tsirkin wrote:
>>>> On Mon, Apr 10, 2023 at 06:24:19PM +0900, Shunsuke Mie wrote:
>>>>> Fix the build dependency for virtio_test. virtio_ring requires
>>>>> container_of_const() and struce device.
>>>>>
>>>>> Signed-off-by: Shunsuke Mie <mie@igel.co.jp>
>>>>> ---
>>>>>    tools/include/linux/container_of.h | 36
>>>>> ++++++++++++++++++++++++++++++
>>>>>    tools/virtio/linux/compiler.h      |  3 +++
>>>>>    tools/virtio/linux/kernel.h        |  5 +----
>>>>>    tools/virtio/linux/module.h        |  1 +
>>>>>    4 files changed, 41 insertions(+), 4 deletions(-)
>>>>>    create mode 100644 tools/include/linux/container_of.h
>>>>>
>>>>> diff --git a/tools/include/linux/container_of.h
>>>>> b/tools/include/linux/container_of.h
>>>>> new file mode 100644
>>>>> index 000000000000..06e293b7cfda
>>>>> --- /dev/null
>>>>> +++ b/tools/include/linux/container_of.h
>>>>> @@ -0,0 +1,36 @@
>>>>> +/* SPDX-License-Identifier: GPL-2.0 */
>>>>> +#ifndef _LINUX_CONTAINER_OF_H
>>>>> +#define _LINUX_CONTAINER_OF_H
>>>>> +
>>>>> +#include <linux/build_bug.h>
>>>>> +#include <linux/stddef.h>
>>>>> +
>>>>> +/**
>>>>> + * container_of - cast a member of a structure out to the
>>>>> containing structure
>>>>> + * @ptr:    the pointer to the member.
>>>>> + * @type:    the type of the container struct this is embedded in.
>>>>> + * @member:    the name of the member within the struct.
>>>>> + *
>>>>> + * WARNING: any const qualifier of @ptr is lost.
>>>>> + */
>>>>> +#define container_of(ptr, type, member) ({                \
>>>>> +    void *__mptr = (void *)(ptr);                    \
>>>>> +    static_assert(__same_type(*(ptr), ((type *)0)->member) ||    \
>>>>> +              __same_type(*(ptr), void),            \
>>>>> +              "pointer type mismatch in container_of()"); \
>>>>> +    ((type *)(__mptr - offsetof(type, member))); })
>>>>> +
>>>>> +/**
>>>>> + * container_of_const - cast a member of a structure out to the
>>>>> containing
>>>>> + *            structure and preserve the const-ness of the pointer
>>>>> + * @ptr:        the pointer to the member
>>>>> + * @type:        the type of the container struct this is embedded in.
>>>>> + * @member:        the name of the member within the struct.
>>>>> + */
>>>>> +#define container_of_const(ptr, type, member) \
>>>>> +    _Generic(ptr,                            \
>>>>> +        const typeof(*(ptr)) *: ((const type
>>>>> *)container_of(ptr, type, member)),\
>>>>> +        default: ((type *)container_of(ptr, type, member)) \
>>>>> +    )
>>>>> +
>>>>> +#endif    /* _LINUX_CONTAINER_OF_H */
>>>> Please just do
>>>> #include "../../../include/linux/container_of.h"
>>>> instead.
>>> Okey, I'll do that.
>>>>
>>>>> diff --git a/tools/virtio/linux/compiler.h
>>>>> b/tools/virtio/linux/compiler.h
>>>>> index 2c51bccb97bb..ac27b3ea6e67 100644
>>>>> --- a/tools/virtio/linux/compiler.h
>>>>> +++ b/tools/virtio/linux/compiler.h
>>>>> @@ -8,4 +8,7 @@
>>>>>    #define READ_ONCE(var) (*((volatile typeof(var) *)(&(var))))
>>>>>      #define __aligned(x) __attribute((__aligned__(x)))
>>>>> +
>>>>> +#define __same_type(a, b)
>>>>> __builtin_types_compatible_p(typeof(a), typeof(b))
>>>>> +
>>>>>    #endif
>>>> #include "../../../include/linux/compiler_types.h" instead?
>>> I'll try it.
>>>>> diff --git a/tools/virtio/linux/kernel.h b/tools/virtio/linux/kernel.h
>>>>> index 8b877167933d..3cd20cb92649 100644
>>>>> --- a/tools/virtio/linux/kernel.h
>>>>> +++ b/tools/virtio/linux/kernel.h
>>>>> @@ -10,6 +10,7 @@
>>>>>    #include <stdarg.h>
>>>>>      #include <linux/compiler.h>
>>>>> +#include <linux/container_of.h>
>>>>>    #include <linux/log2.h>
>>>>>    #include <linux/types.h>
>>>>>    #include <linux/overflow.h>
>>>>> @@ -107,10 +108,6 @@ static inline void free_page(unsigned long addr)
>>>>>        free((void *)addr);
>>>>>    }
>>>>>    -#define container_of(ptr, type, member) ({            \
>>>>> -    const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
>>>>> -    (type *)( (char *)__mptr - offsetof(type,member) );})
>>>>> -
>>>>>    # ifndef likely
>>>>>    #  define likely(x)    (__builtin_expect(!!(x), 1))
>>>>>    # endif
>>>>> diff --git a/tools/virtio/linux/module.h b/tools/virtio/linux/module.h
>>>>> index 9dfa96fea2b2..e2e791dbd104 100644
>>>>> --- a/tools/virtio/linux/module.h
>>>>> +++ b/tools/virtio/linux/module.h
>>>>> @@ -5,3 +5,4 @@
>>>>>        static __attribute__((unused)) const char
>>>>> *__MODULE_LICENSE_name = \
>>>>>            __MODULE_LICENSE_value
>>>>>    +struct device;
>>>> It's not there in include/linux/module - pls put it in the
>>>> same here where it is for linux.
>>> I understood. I'll add some files that has the definition.
>> In vringh.c, 'struct device' is used in virtio_ring.h. Upon investigating
>> the preprocessed file, it was
>>
>> discovered that 'struct device' is defined in bitmap.h, which is included
>> from architecture-specific headers.
>>
>> On x86, the nesting includes
>>
>> 'linux/module.h' -> ... -> 'arch/x86/include/asm/msr.h' ->
>> 'arch/x86/include/asm/cpumask.h' -> 'linux/cpumask.h' -> 'linux/bitmap.h'.
>>
>> Could you advise on the appropriate way to include this file?
> Let's just add struct device; in virtio_ring.h, make it
> self-sufficient.
>
I agree. Thanks a lot.

>>>>> -- 
>>>>> 2.25.1
>>> Best regards,
>>>
>>> Shunsuke.
>>>