Re: [PATCH v4 1/4] bpf: Make the bpf_prog_array_map more generic

From: Alexei Starovoitov
Date: Wed Jul 29 2015 - 21:44:19 EST


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.

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