On Sat, Apr 2, 2022 at 6:35 AM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote:
>
> Joanne Koong <joannekoong@xxxxxx> writes:
>
> > From: Joanne Koong <joannelkoong@xxxxxxxxx>
> >
> > This patch adds two helper functions, bpf_dynptr_read and
> > bpf_dynptr_write:
> >
> > long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset);
> >
> > long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len);
> >
> > The dynptr passed into these functions must be valid dynptrs that have
> > been initialized.
> >
> > Signed-off-by: Joanne Koong <joannelkoong@xxxxxxxxx>
> > ---
> > include/linux/bpf.h | 6 ++++
> > include/uapi/linux/bpf.h | 18 +++++++++++
> > kernel/bpf/helpers.c | 56 ++++++++++++++++++++++++++++++++++
> > tools/include/uapi/linux/bpf.h | 18 +++++++++++
> > 4 files changed, 98 insertions(+)
> >
> > diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> > index e0fcff9f2aee..cded9753fb7f 100644
> > --- a/include/linux/bpf.h
> > +++ b/include/linux/bpf.h
> > @@ -2426,6 +2426,12 @@ enum bpf_dynptr_type {
> > #define DYNPTR_MAX_SIZE ((1UL << 28) - 1)
> > #define DYNPTR_SIZE_MASK 0xFFFFFFF
> > #define DYNPTR_TYPE_SHIFT 29
> > +#define DYNPTR_RDONLY_BIT BIT(28)
> > +
> > +static inline bool bpf_dynptr_is_rdonly(struct bpf_dynptr_kern *ptr)
> > +{
> > + return ptr->size & DYNPTR_RDONLY_BIT;
> > +}
> >
> > static inline enum bpf_dynptr_type bpf_dynptr_get_type(struct bpf_dynptr_kern *ptr)
> > {
> > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > index 6a57d8a1b882..16a35e46be90 100644
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -5175,6 +5175,22 @@ union bpf_attr {
> > * After this operation, *ptr* will be an invalidated dynptr.
> > * Return
> > * Void.
> > + *
> > + * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset)
> > + * Description
> > + * Read *len* bytes from *src* into *dst*, starting from *offset*
> > + * into *dst*.
>
> nit: this should be "starting from *offset* into *src*, no? (same below)
>
Yes, this should be "starting from *offset* into *src*". I will fix
this line in both places. Thanks!
> -Toke
>
