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ac9f06050a
Introduce bpf_obj_drop, which is the kfunc used to free allocated
objects (allocated using bpf_obj_new). Pairing with bpf_obj_new, it
implicitly destructs the fields part of object automatically without
user intervention.
Just like the previous patch, btf_struct_meta that is needed to free up
the special fields is passed as a hidden argument to the kfunc.
For the user, a convenience macro hides over the kernel side kfunc which
is named bpf_obj_drop_impl.
Continuing the previous example:
void prog(void) {
struct foo *f;
f = bpf_obj_new(typeof(*f));
if (!f)
return;
bpf_obj_drop(f);
}
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-15-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
38 lines
1.2 KiB
C
38 lines
1.2 KiB
C
#ifndef __BPF_EXPERIMENTAL__
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#define __BPF_EXPERIMENTAL__
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#include <vmlinux.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_core_read.h>
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/* Description
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* Allocates an object of the type represented by 'local_type_id' in
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* program BTF. User may use the bpf_core_type_id_local macro to pass the
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* type ID of a struct in program BTF.
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*
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* The 'local_type_id' parameter must be a known constant.
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* The 'meta' parameter is a hidden argument that is ignored.
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* Returns
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* A pointer to an object of the type corresponding to the passed in
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* 'local_type_id', or NULL on failure.
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*/
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extern void *bpf_obj_new_impl(__u64 local_type_id, void *meta) __ksym;
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/* Convenience macro to wrap over bpf_obj_new_impl */
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#define bpf_obj_new(type) ((type *)bpf_obj_new_impl(bpf_core_type_id_local(type), NULL))
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/* Description
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* Free an allocated object. All fields of the object that require
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* destruction will be destructed before the storage is freed.
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*
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* The 'meta' parameter is a hidden argument that is ignored.
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* Returns
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* Void.
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*/
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extern void bpf_obj_drop_impl(void *kptr, void *meta) __ksym;
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/* Convenience macro to wrap over bpf_obj_drop_impl */
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#define bpf_obj_drop(kptr) bpf_obj_drop_impl(kptr, NULL)
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#endif
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