Messages in this thread | | | Subject | Re: [PATCH v4 1/4] bpf: Make the bpf_prog_array_map more generic | From | Alexei Starovoitov <> | Date | Fri, 31 Jul 2015 08:46:08 -0700 |
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On 7/31/15 1:50 AM, xiakaixu wrote: > 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.
ahh, yes, you're correct. There is no circular dependency.
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