bpf: Fix a compilation failure with clang lto build

When building the kernel with clang lto (CONFIG_LTO_CLANG_FULL=y), the
following compilation error will appear:

  $ make LLVM=1 LLVM_IAS=1 -j
  ...
  ld.lld: error: ld-temp.o <inline asm>:26889:1: symbol 'cgroup_storage_map_btf_ids' is already defined
  cgroup_storage_map_btf_ids:;
  ^
  make[1]: *** [/.../bpf-next/scripts/Makefile.vmlinux_o:61: vmlinux.o] Error 1

In local_storage.c, we have
  BTF_ID_LIST_SINGLE(cgroup_storage_map_btf_ids, struct, bpf_local_storage_map)
Commit c4bcfb3 ("bpf: Implement cgroup storage available to
non-cgroup-attached bpf progs") added the above identical BTF_ID_LIST_SINGLE
definition in bpf_cgrp_storage.c. With duplicated definitions, llvm linker
complains with lto build.

Also, extracting btf_id of 'struct bpf_local_storage_map' is defined four times
for sk, inode, task and cgrp local storages. Let us define a single global one
with a different name than cgroup_storage_map_btf_ids, which also fixed
the lto compilation error.

Fixes: c4bcfb3 ("bpf: Implement cgroup storage available to non-cgroup-attached bpf progs")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221130052147.1591625-1-yhs@fb.com

include/linux/btf_ids.h

@@ -266,5 +266,6 @@ MAX_BTF_TRACING_TYPE,
 
 extern u32 btf_tracing_ids[];
 extern u32 bpf_cgroup_btf_id[];
+extern u32 bpf_local_storage_map_btf_id[];
 
 #endif

kernel/bpf/bpf_cgrp_storage.c

@@ -211,7 +211,6 @@ BPF_CALL_2(bpf_cgrp_storage_delete, struct bpf_map *, map, struct cgroup *, cgro
 	return ret;
 }
 
-BTF_ID_LIST_SINGLE(cgroup_storage_map_btf_ids, struct, bpf_local_storage_map)
 const struct bpf_map_ops cgrp_storage_map_ops = {
 	.map_meta_equal = bpf_map_meta_equal,
 	.map_alloc_check = bpf_local_storage_map_alloc_check,
@@ -222,7 +221,7 @@ const struct bpf_map_ops cgrp_storage_map_ops = {
 	.map_update_elem = bpf_cgrp_storage_update_elem,
 	.map_delete_elem = bpf_cgrp_storage_delete_elem,
 	.map_check_btf = bpf_local_storage_map_check_btf,
-	.map_btf_id = &cgroup_storage_map_btf_ids[0],
+	.map_btf_id = &bpf_local_storage_map_btf_id[0],
 	.map_owner_storage_ptr = cgroup_storage_ptr,
 };
 

kernel/bpf/bpf_inode_storage.c

@@ -213,8 +213,6 @@ static void inode_storage_map_free(struct bpf_map *map)
 	bpf_local_storage_map_free(map, &inode_cache, NULL);
 }
 
-BTF_ID_LIST_SINGLE(inode_storage_map_btf_ids, struct,
-		   bpf_local_storage_map)
 const struct bpf_map_ops inode_storage_map_ops = {
 	.map_meta_equal = bpf_map_meta_equal,
 	.map_alloc_check = bpf_local_storage_map_alloc_check,
@@ -225,7 +223,7 @@ const struct bpf_map_ops inode_storage_map_ops = {
 	.map_update_elem = bpf_fd_inode_storage_update_elem,
 	.map_delete_elem = bpf_fd_inode_storage_delete_elem,
 	.map_check_btf = bpf_local_storage_map_check_btf,
-	.map_btf_id = &inode_storage_map_btf_ids[0],
+	.map_btf_id = &bpf_local_storage_map_btf_id[0],
 	.map_owner_storage_ptr = inode_storage_ptr,
 };
 

kernel/bpf/bpf_task_storage.c

@@ -324,7 +324,7 @@ static void task_storage_map_free(struct bpf_map *map)
 	bpf_local_storage_map_free(map, &task_cache, &bpf_task_storage_busy);
 }
 
-BTF_ID_LIST_SINGLE(task_storage_map_btf_ids, struct, bpf_local_storage_map)
+BTF_ID_LIST_GLOBAL_SINGLE(bpf_local_storage_map_btf_id, struct, bpf_local_storage_map)
 const struct bpf_map_ops task_storage_map_ops = {
 	.map_meta_equal = bpf_map_meta_equal,
 	.map_alloc_check = bpf_local_storage_map_alloc_check,
@@ -335,7 +335,7 @@ const struct bpf_map_ops task_storage_map_ops = {
 	.map_update_elem = bpf_pid_task_storage_update_elem,
 	.map_delete_elem = bpf_pid_task_storage_delete_elem,
 	.map_check_btf = bpf_local_storage_map_check_btf,
-	.map_btf_id = &task_storage_map_btf_ids[0],
+	.map_btf_id = &bpf_local_storage_map_btf_id[0],
 	.map_owner_storage_ptr = task_storage_ptr,
 };
 

net/core/bpf_sk_storage.c

@@ -310,7 +310,6 @@ bpf_sk_storage_ptr(void *owner)
 	return &sk->sk_bpf_storage;
 }
 
-BTF_ID_LIST_SINGLE(sk_storage_map_btf_ids, struct, bpf_local_storage_map)
 const struct bpf_map_ops sk_storage_map_ops = {
 	.map_meta_equal = bpf_map_meta_equal,
 	.map_alloc_check = bpf_local_storage_map_alloc_check,
@@ -321,7 +320,7 @@ const struct bpf_map_ops sk_storage_map_ops = {
 	.map_update_elem = bpf_fd_sk_storage_update_elem,
 	.map_delete_elem = bpf_fd_sk_storage_delete_elem,
 	.map_check_btf = bpf_local_storage_map_check_btf,
-	.map_btf_id = &sk_storage_map_btf_ids[0],
+	.map_btf_id = &bpf_local_storage_map_btf_id[0],
 	.map_local_storage_charge = bpf_sk_storage_charge,
 	.map_local_storage_uncharge = bpf_sk_storage_uncharge,
 	.map_owner_storage_ptr = bpf_sk_storage_ptr,