[bpf-next,07/16] libbpf: Add helpers for bpf_dynptr_user

Commit Message

Hou Tao Oct. 8, 2024, 9:14 a.m. UTC

From: Hou Tao <[e-mail]>

Add bpf_dynptr_user_init() to initialize a bpf_dynptr_user object,
bpf_dynptr_user_{data,size}() to get the address and length of the
dynptr object, and bpf_dynptr_user_set_size() to set the its size.

Instead of exporting these symbols, simply adding these helpers as
inline functions in bpf.h.

Signed-off-by: Hou Tao <[e-mail]>
---
 tools/lib/bpf/bpf.h | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

Comments

Andrii Nakryiko Oct. 10, 2024, 9:50 p.m. UTC | #1

On Tue, Oct 8, 2024 at 2:02 AM Hou Tao <[e-mail]> wrote:
>
> From: Hou Tao <[e-mail]>
>
> Add bpf_dynptr_user_init() to initialize a bpf_dynptr_user object,
> bpf_dynptr_user_{data,size}() to get the address and length of the
> dynptr object, and bpf_dynptr_user_set_size() to set the its size.
>
> Instead of exporting these symbols, simply adding these helpers as
> inline functions in bpf.h.
>
> Signed-off-by: Hou Tao <[e-mail]>
> ---
>  tools/lib/bpf/bpf.h | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
>

I don't think we need this patch and these APIs at all, let user work
with bpf_udynptr directly


> diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
> index a4a7b1ad1b63..92b4afac5f5f 100644
> --- a/tools/lib/bpf/bpf.h
> +++ b/tools/lib/bpf/bpf.h
> @@ -700,6 +700,33 @@ struct bpf_token_create_opts {
>  LIBBPF_API int bpf_token_create(int bpffs_fd,
>                                 struct bpf_token_create_opts *opts);
>
> +/* sys_bpf() will check the validity of data and size */
> +static inline void bpf_dynptr_user_init(void *data, __u32 size,
> +                                       struct bpf_dynptr_user *dynptr)
> +{
> +       dynptr->data = (__u64)(unsigned long)data;
> +       dynptr->size = size;
> +       dynptr->rsvd = 0;
> +}
> +
> +static inline void bpf_dynptr_user_set_size(struct bpf_dynptr_user *dynptr,
> +                                           __u32 new_size)
> +{
> +       dynptr->size = new_size;
> +}
> +
> +static inline __u32
> +bpf_dynptr_user_size(const struct bpf_dynptr_user *dynptr)
> +{
> +       return dynptr->size;
> +}
> +
> +static inline void *
> +bpf_dynptr_user_data(const struct bpf_dynptr_user *dynptr)
> +{
> +       return (void *)(unsigned long)dynptr->data;
> +}
> +
>  #ifdef __cplusplus
>  } /* extern "C" */
>  #endif
> --
> 2.44.0
>

Hou Tao Oct. 21, 2024, 1:51 p.m. UTC | #2

Hi,

On 10/11/2024 5:50 AM, Andrii Nakryiko wrote:
> On Tue, Oct 8, 2024 at 2:02 AM Hou Tao <[e-mail]> wrote:
>> From: Hou Tao <[e-mail]>
>>
>> Add bpf_dynptr_user_init() to initialize a bpf_dynptr_user object,
>> bpf_dynptr_user_{data,size}() to get the address and length of the
>> dynptr object, and bpf_dynptr_user_set_size() to set the its size.
>>
>> Instead of exporting these symbols, simply adding these helpers as
>> inline functions in bpf.h.
>>
>> Signed-off-by: Hou Tao <[e-mail]>
>> ---
>>  tools/lib/bpf/bpf.h | 27 +++++++++++++++++++++++++++
>>  1 file changed, 27 insertions(+)
>>
> I don't think we need this patch and these APIs at all, let user work
> with bpf_udynptr directly

Got it. Will drop it in v2.
>
>> diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
>> index a4a7b1ad1b63..92b4afac5f5f 100644
>> --- a/tools/lib/bpf/bpf.h
>> +++ b/tools/lib/bpf/bpf.h
>> @@ -700,6 +700,33 @@ struct bpf_token_create_opts {
>>  LIBBPF_API int bpf_token_create(int bpffs_fd,
>>                                 struct bpf_token_create_opts *opts);
>>
>> +/* sys_bpf() will check the validity of data and size */
>> +static inline void bpf_dynptr_user_init(void *data, __u32 size,
>> +                                       struct bpf_dynptr_user *dynptr)
>> +{
>> +       dynptr->data = (__u64)(unsigned long)data;
>> +       dynptr->size = size;
>> +       dynptr->rsvd = 0;
>> +}
>> +
>> +static inline void bpf_dynptr_user_set_size(struct bpf_dynptr_user *dynptr,
>> +                                           __u32 new_size)
>> +{
>> +       dynptr->size = new_size;
>> +}
>> +
>> +static inline __u32
>> +bpf_dynptr_user_size(const struct bpf_dynptr_user *dynptr)
>> +{
>> +       return dynptr->size;
>> +}
>> +
>> +static inline void *
>> +bpf_dynptr_user_data(const struct bpf_dynptr_user *dynptr)
>> +{
>> +       return (void *)(unsigned long)dynptr->data;
>> +}
>> +
>>  #ifdef __cplusplus
>>  } /* extern "C" */
>>  #endif
>> --
>> 2.44.0
>>

Patch

diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index a4a7b1ad1b63..92b4afac5f5f 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -700,6 +700,33 @@  struct bpf_token_create_opts {
 LIBBPF_API int bpf_token_create(int bpffs_fd,
 				struct bpf_token_create_opts *opts);
 
+/* sys_bpf() will check the validity of data and size */
+static inline void bpf_dynptr_user_init(void *data, __u32 size,
+					struct bpf_dynptr_user *dynptr)
+{
+	dynptr->data = (__u64)(unsigned long)data;
+	dynptr->size = size;
+	dynptr->rsvd = 0;
+}
+
+static inline void bpf_dynptr_user_set_size(struct bpf_dynptr_user *dynptr,
+					    __u32 new_size)
+{
+	dynptr->size = new_size;
+}
+
+static inline __u32
+bpf_dynptr_user_size(const struct bpf_dynptr_user *dynptr)
+{
+	return dynptr->size;
+}
+
+static inline void *
+bpf_dynptr_user_data(const struct bpf_dynptr_user *dynptr)
+{
+	return (void *)(unsigned long)dynptr->data;
+}
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif