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| author | Andrii Nakryiko <andriin@fb.com> | 2019-11-17 09:28:03 -0800 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2019-11-18 11:41:59 +0100 |
| commit | 85192dbf4de08795afe2b88e52a36fc6abfc3dba (patch) | |
| tree | 52379ced52c2c2ed5f023073a1aeeb52779e376d /kernel/bpf/syscall.c | |
| parent | 1e0bd5a091e5d9e0f1d5b0e6329b87bb1792f784 (diff) | |
| download | linux-85192dbf4de08795afe2b88e52a36fc6abfc3dba.tar.gz linux-85192dbf4de08795afe2b88e52a36fc6abfc3dba.tar.bz2 linux-85192dbf4de08795afe2b88e52a36fc6abfc3dba.zip | |
bpf: Convert bpf_prog refcnt to atomic64_t
Similarly to bpf_map's refcnt/usercnt, convert bpf_prog's refcnt to atomic64
and remove artificial 32k limit. This allows to make bpf_prog's refcounting
non-failing, simplifying logic of users of bpf_prog_add/bpf_prog_inc.
Validated compilation by running allyesconfig kernel build.
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191117172806.2195367-3-andriin@fb.com
Diffstat (limited to 'kernel/bpf/syscall.c')
| -rw-r--r-- | kernel/bpf/syscall.c | 30 |
1 files changed, 9 insertions, 21 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 20030751b7a2..52fe4bacb330 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1339,7 +1339,7 @@ static void __bpf_prog_put_noref(struct bpf_prog *prog, bool deferred) static void __bpf_prog_put(struct bpf_prog *prog, bool do_idr_lock) { - if (atomic_dec_and_test(&prog->aux->refcnt)) { + if (atomic64_dec_and_test(&prog->aux->refcnt)) { perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_UNLOAD, 0); /* bpf_prog_free_id() must be called first */ bpf_prog_free_id(prog, do_idr_lock); @@ -1445,16 +1445,9 @@ static struct bpf_prog *____bpf_prog_get(struct fd f) return f.file->private_data; } -/* prog's refcnt limit */ -#define BPF_MAX_REFCNT 32768 - -struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i) +void bpf_prog_add(struct bpf_prog *prog, int i) { - if (atomic_add_return(i, &prog->aux->refcnt) > BPF_MAX_REFCNT) { - atomic_sub(i, &prog->aux->refcnt); - return ERR_PTR(-EBUSY); - } - return prog; + atomic64_add(i, &prog->aux->refcnt); } EXPORT_SYMBOL_GPL(bpf_prog_add); @@ -1465,13 +1458,13 @@ void bpf_prog_sub(struct bpf_prog *prog, int i) * path holds a reference to the program, thus atomic_sub() can * be safely used in such cases! */ - WARN_ON(atomic_sub_return(i, &prog->aux->refcnt) == 0); + WARN_ON(atomic64_sub_return(i, &prog->aux->refcnt) == 0); } EXPORT_SYMBOL_GPL(bpf_prog_sub); -struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) +void bpf_prog_inc(struct bpf_prog *prog) { - return bpf_prog_add(prog, 1); + atomic64_inc(&prog->aux->refcnt); } EXPORT_SYMBOL_GPL(bpf_prog_inc); @@ -1480,12 +1473,7 @@ struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog) { int refold; - refold = atomic_fetch_add_unless(&prog->aux->refcnt, 1, 0); - - if (refold >= BPF_MAX_REFCNT) { - __bpf_prog_put(prog, false); - return ERR_PTR(-EBUSY); - } + refold = atomic64_fetch_add_unless(&prog->aux->refcnt, 1, 0); if (!refold) return ERR_PTR(-ENOENT); @@ -1523,7 +1511,7 @@ static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *attach_type, goto out; } - prog = bpf_prog_inc(prog); + bpf_prog_inc(prog); out: fdput(f); return prog; @@ -1714,7 +1702,7 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr) prog->orig_prog = NULL; prog->jited = 0; - atomic_set(&prog->aux->refcnt, 1); + atomic64_set(&prog->aux->refcnt, 1); prog->gpl_compatible = is_gpl ? 1 : 0; if (bpf_prog_is_dev_bound(prog->aux)) { |