Messages in this thread Patch in this message | | | Date | Wed, 20 Apr 2016 16:30:43 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [RFC PATCH 06/13] bpf tools: Introduce ubpf_vm to program instance union |
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Em Wed, Apr 20, 2016 at 06:01:46PM +0000, Wang Nan escreveu: > Add 'struct ubpf_vm *' into prog_instance union. Introduce if_engine() > macro to merge common code. > > Signed-off-by: Wang Nan <wangnan0@huawei.com> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > Cc: Alexei Starovoitov <ast@kernel.org> > Cc: Brendan Gregg <brendan.d.gregg@gmail.com> > Cc: Jiri Olsa <jolsa@kernel.org> > Cc: Li Zefan <lizefan@huawei.com> > --- > tools/lib/bpf/libbpf.c | 76 ++++++++++++++++++++++++++++++++++++++++++++------ > 1 file changed, 68 insertions(+), 8 deletions(-) > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index 3755846..3a969fd 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -141,6 +141,9 @@ int libbpf_strerror(int err, char *buf, size_t size) > > union prog_instance { > int fd; > +#ifdef HAVE_UBPF_SUPPORT > + struct ubpf_vm *vm; > +#endif > }; > > /* > @@ -176,6 +179,56 @@ struct bpf_program { > bpf_program_clear_priv_t clear_priv; > }; > > +#ifdef HAVE_UBPF_SUPPORT > +# define __if_engine(p, d, k, u) \ > + do { \ > + switch (p->engine) { \ > + default: \ > + case ENGINE_UNKNOWN: { \ > + d; \ > + } \ > + case ENGINE_KBPF: { \ > + k; break; \ > + } \ > + case ENGINE_UBPF: { \ > + u; break; \ > + } \ > + } \ > + } while(0)
These macro tricks are getting unecessarily overly complicated :-\
> + > +/* > + * ubpf_destroy() doesn't accept NULL input. This wrapper makes > + * it similar to zclose. > + */ > +# define __ubpf_destroy(vm) do { \ > + if (vm) \ > + ubpf_destroy(vm); \ > + (vm) = NULL; \ > +} while(0) > + > +#else > +# define __if_engine(p, d, k, u) \ > + do { k; } while(0) > +#endif
Why use just one letter parameters, give them proper names
> + > +#define instan_fd(i) instances.array[i].fd > +#define instan_vm(i) instances.array[i].vm > + > +#define if_engine(p, k, u) __if_engine(p, do { } while(0), k, u) > +#define set_instance(p, i, k, u) \ > + if_engine(p, \ > + p->instan_fd(i) = k, \ > + p->instan_vm(i) = u)
If you had used a void pointer for instances->entries you wouldn't have to play such tricks, right?
> + > +static inline void init_instance_array(struct bpf_program *prog) > +{ > + size_t size = sizeof(prog->instances.array[0]) * prog->instances.nr; > + > + if_engine(prog, > + memset(prog->instances.array, -1, size), > + memset(prog->instances.array, 0, size)); > +}
> + > struct bpf_map { > int fd; > char *name; > @@ -239,7 +292,9 @@ static void bpf_program__unload(struct bpf_program *prog) > */ > if (prog->instances.nr > 0) { > for (i = 0; i < prog->instances.nr; i++) > - zclose(prog->instances.array[i].fd); > + if_engine(prog, > + zclose(prog->instan_fd(i)), > + __ubpf_destroy(prog->instan_vm(i)));
So if we have more types of instances this will become a switch_engine()?
> } else if (prog->instances.nr != -1) { > pr_warning("Internal error: instances.nr is %d\n", > prog->instances.nr); > @@ -966,7 +1021,7 @@ bpf_program__load(struct bpf_program *prog, > return -ENOMEM; > } > prog->instances.nr = 1; > - prog->instances.array[0].fd = -1; > + set_instance(prog, 0, -1, NULL);
And here we would go on adding more and more values? Why not have some
struct bpf_engine { void (*init)(struct bpf_program *prog); void (*fini)(struct bpf_program *prog); } One for the kernel "engine", the other for the userspace one?
> } > > if (!prog->preprocessor) { > @@ -977,7 +1032,7 @@ bpf_program__load(struct bpf_program *prog, > err = load_program(prog->insns, prog->insns_cnt, > license, kern_version, &fd); > if (!err) > - prog->instances.array[0].fd = fd; > + prog->instan_fd(0) = fd; > goto out; > } > > @@ -997,7 +1052,7 @@ bpf_program__load(struct bpf_program *prog, > if (!result.new_insn_ptr || !result.new_insn_cnt) { > pr_debug("Skip loading the %dth instance of program '%s'\n", > i, prog->section_name); > - prog->instances.array[i].fd = -1; > + prog->instan_fd(i) = -1; > if (result.pfd) > *result.pfd = -1; > continue; > @@ -1015,7 +1070,7 @@ bpf_program__load(struct bpf_program *prog, > > if (result.pfd) > *result.pfd = fd; > - prog->instances.array[i].fd = fd; > + prog->instan_fd(i) = fd; > } > out: > if (err) > @@ -1301,12 +1356,11 @@ int bpf_program__set_prep(struct bpf_program *prog, int nr_instances, > return -ENOMEM; > } > > - /* fill all fd with -1 */ > - memset(array, -1, sizeof(array[0]) * nr_instances); > - > prog->instances.nr = nr_instances; > prog->instances.array = array; > prog->preprocessor = prep; > + > + init_instance_array(prog); > return 0; > } > > @@ -1314,6 +1368,12 @@ int bpf_program__nth_fd(struct bpf_program *prog, int n) > { > int fd; > > + if (prog->engine != ENGINE_KBPF) { > + pr_warning("Can't get fd from program %s: engine not KBPF or not loaded\n", > + prog->section_name); > + return -EINVAL; > + } > + > if (n >= prog->instances.nr || n < 0) { > pr_warning("Can't get the %dth fd from program %s: only %d instances\n", > n, prog->section_name, prog->instances.nr); > -- > 1.8.3.4
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