KFunc bpf_refcount_acquire_impl
Increment the refcount on a refcounted local kptr, turning the non-owning reference input into an owning reference in the process.
Note
This kfunc is deprecated as of 7.1, replaced by bpf_refcount_acquire. This kfunc will be removed at some point in the future.
Definition
The meta parameter is rewritten by the verifier, no need for BPF program to set it.
Returns
An owning reference to the object pointed to by kptr
Signature
void *bpf_refcount_acquire_impl(void *p__refcounted_kptr, void *meta__ign)
Note
This kfunc returns a pointer to a refcounted object. The verifier will then ensure that the pointer to the object
is eventually released using a release kfunc, or transferred to a map using a referenced kptr
(by invoking bpf_kptr_xchg). If not, the verifier fails the
loading of the BPF program until no lingering references remain in all possible explored states of the program.
Note
The pointer returned by the kfunc may be NULL. Hence, it forces the user to do a NULL check on the pointer returned from the kfunc before making use of it (dereferencing or passing to another helper).
Usage
Docs could be improved
This part of the docs is incomplete, contributions are very welcome
Program types
The following program types can make use of this kfunc:
Example
Docs could be improved
This part of the docs is incomplete, contributions are very welcome