| Message ID | 1468955817-10604-2-git-send-email-bblanco@plumgrid.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Tue, Jul 19, 2016 at 12:16:46PM -0700, Brenden Blanco wrote: > A subsystem may need to store many copies of a bpf program, each > deserving its own reference. Rather than requiring the caller to loop > one by one (with possible mid-loop failure), add a bulk bpf_prog_add > api. > > Signed-off-by: Brenden Blanco <bblanco@plumgrid.com> > --- > include/linux/bpf.h | 1 + > kernel/bpf/syscall.c | 12 +++++++++--- > 2 files changed, 10 insertions(+), 3 deletions(-) > > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > index c13e92b..75a5ae6 100644 > --- a/include/linux/bpf.h > +++ b/include/linux/bpf.h > @@ -224,6 +224,7 @@ void bpf_register_map_type(struct bpf_map_type_list *tl); > > struct bpf_prog *bpf_prog_get(u32 ufd); > struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type); > +struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i); > struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog); > void bpf_prog_put(struct bpf_prog *prog); > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index 96d938a..228f962 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -670,14 +670,20 @@ static struct bpf_prog *____bpf_prog_get(struct fd f) > return f.file->private_data; > } > > -struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) > +struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i) > { > - if (atomic_inc_return(&prog->aux->refcnt) > BPF_MAX_REFCNT) { > - atomic_dec(&prog->aux->refcnt); > + if (atomic_add_return(i, &prog->aux->refcnt) > BPF_MAX_REFCNT) { > + atomic_sub(i, &prog->aux->refcnt); > return ERR_PTR(-EBUSY); > } > return prog; > } > +EXPORT_SYMBOL_GPL(bpf_prog_add); > + > +struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) > +{ > + return bpf_prog_add(prog, 1); > +} that extension turned out to be smaller than I thought :) Acked-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index c13e92b..75a5ae6 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -224,6 +224,7 @@ void bpf_register_map_type(struct bpf_map_type_list *tl); struct bpf_prog *bpf_prog_get(u32 ufd); struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type); +struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i); struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog); void bpf_prog_put(struct bpf_prog *prog); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 96d938a..228f962 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -670,14 +670,20 @@ static struct bpf_prog *____bpf_prog_get(struct fd f) return f.file->private_data; } -struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) +struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i) { - if (atomic_inc_return(&prog->aux->refcnt) > BPF_MAX_REFCNT) { - atomic_dec(&prog->aux->refcnt); + if (atomic_add_return(i, &prog->aux->refcnt) > BPF_MAX_REFCNT) { + atomic_sub(i, &prog->aux->refcnt); return ERR_PTR(-EBUSY); } return prog; } +EXPORT_SYMBOL_GPL(bpf_prog_add); + +struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) +{ + return bpf_prog_add(prog, 1); +} static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *type) {
A subsystem may need to store many copies of a bpf program, each deserving its own reference. Rather than requiring the caller to loop one by one (with possible mid-loop failure), add a bulk bpf_prog_add api. Signed-off-by: Brenden Blanco <bblanco@plumgrid.com> --- include/linux/bpf.h | 1 + kernel/bpf/syscall.c | 12 +++++++++--- 2 files changed, 10 insertions(+), 3 deletions(-)