Re: [PATCH bpf-next 1/6] bpf: rename stack trace map operations

On 10/08/2018 08:40 PM, Song Liu wrote:

Actually, does it make sense to implement a list_map that supports
both pop_head()
and pop_tail()? Maybe gate one of the pop operations with options?

The main issue with this approach is the mapping to the system calls.
Adding a flag would complicate things a bit because lookup nor 
lookup_and_delete have a flag argument.

I am asking because mixing stack with stack trace is still confusing
after this patch.

Thanks,
Song

On Mon, Oct 8, 2018 at 12:11 PM Mauricio Vasquez B
[off-list ref] wrote:

quoted

In the following patches queue and stack maps (FIFO and LIFO
datastructures) will be implemented.  In order to avoid confusion and
a possible name clash rename stack_map_ops to stack_trace_map_ops

Signed-off-by: Mauricio Vasquez B <redacted>
---
  include/linux/bpf_types.h |    2 +-
  kernel/bpf/stackmap.c     |    2 +-
  2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index 5432f4c9f50e..658509daacd4 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h

@@ -51,7 +51,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_LRU_HASH, htab_lru_map_ops)
  BPF_MAP_TYPE(BPF_MAP_TYPE_LRU_PERCPU_HASH, htab_lru_percpu_map_ops)
  BPF_MAP_TYPE(BPF_MAP_TYPE_LPM_TRIE, trie_map_ops)
  #ifdef CONFIG_PERF_EVENTS
-BPF_MAP_TYPE(BPF_MAP_TYPE_STACK_TRACE, stack_map_ops)
+BPF_MAP_TYPE(BPF_MAP_TYPE_STACK_TRACE, stack_trace_map_ops)
  #endif
  BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY_OF_MAPS, array_of_maps_map_ops)
  BPF_MAP_TYPE(BPF_MAP_TYPE_HASH_OF_MAPS, htab_of_maps_map_ops)

diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index 8061a439ef18..bb41e293418d 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c

@@ -600,7 +600,7 @@ static void stack_map_free(struct bpf_map *map)
         put_callchain_buffers();
  }

-const struct bpf_map_ops stack_map_ops = {
+const struct bpf_map_ops stack_trace_map_ops = {
         .map_alloc = stack_map_alloc,
         .map_free = stack_map_free,
         .map_get_next_key = stack_map_get_next_key,