Messages in this thread | | | Date | Fri, 31 Jul 2015 16:50:17 +0800 | From | xiakaixu <> | Subject | Re: [PATCH v4 1/4] bpf: Make the bpf_prog_array_map more generic |
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于 2015/7/30 9:44, Alexei Starovoitov 写道: > On 7/29/15 4:17 PM, Daniel Borkmann wrote: >>> - if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY) >>> + if (map->map_type >= BPF_MAP_TYPE_PROG_ARRAY) >>> /* prog_array stores refcnt-ed bpf_prog pointers >>> * release them all when user space closes prog_array_fd >>> */ >>> - bpf_prog_array_map_clear(map); >>> + bpf_fd_array_map_clear(map); >> >> When we are going to add a new map type to the eBPF framework that is not >> an fd_array_map thing, this assumption of map->map_type >= >> BPF_MAP_TYPE_PROG_ARRAY >> might not hold then ... > > Also I think here changing == to >= is probably unnecessary. > prog_array needs to do it because of circular dependency > whereas perf_event_array cannot have it. > Even when we attach bpf prog to perf_event and then add it to > perf_event_array used by the same prog, right? > Please test such scenario just in case.
Not sure completely understand what you mean. You know, we can attach bpf_prog to kprobe events. For now, we limit few event types, only PERF_EVENT_RAW & PERF_EVENT_HARDWARE event can be accessed in bpf_perf_event_read(). Seems like the dependency scenario won't happen. I will add the event decrement refcnt function to map_free in V5. right? > > > . >
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