bpf: Allow to use kfunc XDP hints and frags together

There is no fundamental reason, why multi-buffer XDP and XDP kfunc RX hints
cannot coexist in a single program.

Allow those features to be used together by modifying the flags condition
for dev-bound-only programs, segments are still prohibited for fully
offloaded programs, hence additional check.

Suggested-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/CAKH8qBuzgtJj=OKMdsxEkyML36VsAuZpcrsXcyqjdKXSJCBq=Q@mail.gmail.com/
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230915083914.65538-1-larysa.zaremba@intel.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
index e7a1752b5a09a6366d3ce6202f49c8027e989f78..92c9df46134a1837b9e9b1196c48ac369c3cb2bc 100644 (file)
--- a/kernel/bpf/offload.c
+++ b/kernel/bpf/offload.c
@@ -232,7 +232,14 @@ int bpf_prog_dev_bound_init(struct bpf_prog *prog, union bpf_attr *attr)
            attr->prog_type != BPF_PROG_TYPE_XDP)
                return -EINVAL;
 
-       if (attr->prog_flags & ~BPF_F_XDP_DEV_BOUND_ONLY)
+       if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS))
+               return -EINVAL;
+
+       /* Frags are allowed only if program is dev-bound-only, but not
+        * if it is requesting bpf offload.
+        */
+       if (attr->prog_flags & BPF_F_XDP_HAS_FRAGS &&
+           !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY))
                return -EINVAL;
 
        if (attr->prog_type == BPF_PROG_TYPE_SCHED_CLS &&