Commit c317ab71 authored by Menglong Dong's avatar Menglong Dong Committed by Alexei Starovoitov
Browse files

bpf: Compute map_btf_id during build time 



For now, the field 'map_btf_id' in 'struct bpf_map_ops' for all map
types are computed during vmlinux-btf init:

  btf_parse_vmlinux() -> btf_vmlinux_map_ids_init()

It will lookup the btf_type according to the 'map_btf_name' field in
'struct bpf_map_ops'. This process can be done during build time,
thanks to Jiri's resolve_btfids.

selftest of map_ptr has passed:

  $96 map_ptr:OK
  Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Reported-by: default avatarkernel test robot <lkp@intel.com>
Signed-off-by: default avatarMenglong Dong <imagedong@tencent.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 367590b7

include/linux/bpf.h

+1 −2
Original line number Diff line number Diff line
@@ -148,8 +148,7 @@ struct bpf_map_ops { 
				     bpf_callback_t callback_fn,

				     void *callback_ctx, u64 flags);



	/* BTF name and id of struct allocated by map_alloc */

	const char * const map_btf_name;

	/* BTF id of struct allocated by map_alloc */

	int *map_btf_id;



	/* bpf_iter info used to open a seq_file */

kernel/bpf/arraymap.c

+8 −18
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/perf_event.h>

#include <uapi/linux/btf.h>

#include <linux/rcupdate_trace.h>

#include <linux/btf_ids.h>



#include "map_in_map.h"
@@ -690,7 +691,7 @@ static int bpf_for_each_array_elem(struct bpf_map *map, bpf_callback_t callback_ 
	return num_elems;

}



static int array_map_btf_id;

BTF_ID_LIST_SINGLE(array_map_btf_ids, struct, bpf_array)

const struct bpf_map_ops array_map_ops = {

	.map_meta_equal = array_map_meta_equal,

	.map_alloc_check = array_map_alloc_check,
@@ -711,12 +712,10 @@ const struct bpf_map_ops array_map_ops = { 
	.map_update_batch = generic_map_update_batch,

	.map_set_for_each_callback_args = map_set_for_each_callback_args,

	.map_for_each_callback = bpf_for_each_array_elem,

	.map_btf_name = "bpf_array",

	.map_btf_id = &array_map_btf_id,

	.map_btf_id = &array_map_btf_ids[0],

	.iter_seq_info = &iter_seq_info,

};



static int percpu_array_map_btf_id;

const struct bpf_map_ops percpu_array_map_ops = {

	.map_meta_equal = bpf_map_meta_equal,

	.map_alloc_check = array_map_alloc_check,
@@ -732,8 +731,7 @@ const struct bpf_map_ops percpu_array_map_ops = { 
	.map_update_batch = generic_map_update_batch,

	.map_set_for_each_callback_args = map_set_for_each_callback_args,

	.map_for_each_callback = bpf_for_each_array_elem,

	.map_btf_name = "bpf_array",

	.map_btf_id = &percpu_array_map_btf_id,

	.map_btf_id = &array_map_btf_ids[0],

	.iter_seq_info = &iter_seq_info,

};
@@ -1112,7 +1110,6 @@ static void prog_array_map_free(struct bpf_map *map) 
 * Thus, prog_array_map cannot be used as an inner_map

 * and map_meta_equal is not implemented.

 */

static int prog_array_map_btf_id;

const struct bpf_map_ops prog_array_map_ops = {

	.map_alloc_check = fd_array_map_alloc_check,

	.map_alloc = prog_array_map_alloc,
@@ -1128,8 +1125,7 @@ const struct bpf_map_ops prog_array_map_ops = { 
	.map_fd_sys_lookup_elem = prog_fd_array_sys_lookup_elem,

	.map_release_uref = prog_array_map_clear,

	.map_seq_show_elem = prog_array_map_seq_show_elem,

	.map_btf_name = "bpf_array",

	.map_btf_id = &prog_array_map_btf_id,

	.map_btf_id = &array_map_btf_ids[0],

};



static struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
@@ -1218,7 +1214,6 @@ static void perf_event_fd_array_map_free(struct bpf_map *map) 
	fd_array_map_free(map);

}



static int perf_event_array_map_btf_id;

const struct bpf_map_ops perf_event_array_map_ops = {

	.map_meta_equal = bpf_map_meta_equal,

	.map_alloc_check = fd_array_map_alloc_check,
@@ -1231,8 +1226,7 @@ const struct bpf_map_ops perf_event_array_map_ops = { 
	.map_fd_put_ptr = perf_event_fd_array_put_ptr,

	.map_release = perf_event_fd_array_release,

	.map_check_btf = map_check_no_btf,

	.map_btf_name = "bpf_array",

	.map_btf_id = &perf_event_array_map_btf_id,

	.map_btf_id = &array_map_btf_ids[0],

};



#ifdef CONFIG_CGROUPS
@@ -1255,7 +1249,6 @@ static void cgroup_fd_array_free(struct bpf_map *map) 
	fd_array_map_free(map);

}



static int cgroup_array_map_btf_id;

const struct bpf_map_ops cgroup_array_map_ops = {

	.map_meta_equal = bpf_map_meta_equal,

	.map_alloc_check = fd_array_map_alloc_check,
@@ -1267,8 +1260,7 @@ const struct bpf_map_ops cgroup_array_map_ops = { 
	.map_fd_get_ptr = cgroup_fd_array_get_ptr,

	.map_fd_put_ptr = cgroup_fd_array_put_ptr,

	.map_check_btf = map_check_no_btf,

	.map_btf_name = "bpf_array",

	.map_btf_id = &cgroup_array_map_btf_id,

	.map_btf_id = &array_map_btf_ids[0],

};

#endif
@@ -1342,7 +1334,6 @@ static int array_of_map_gen_lookup(struct bpf_map *map, 
	return insn - insn_buf;

}



static int array_of_maps_map_btf_id;

const struct bpf_map_ops array_of_maps_map_ops = {

	.map_alloc_check = fd_array_map_alloc_check,

	.map_alloc = array_of_map_alloc,
@@ -1355,6 +1346,5 @@ const struct bpf_map_ops array_of_maps_map_ops = { 
	.map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,

	.map_gen_lookup = array_of_map_gen_lookup,

	.map_check_btf = map_check_no_btf,

	.map_btf_name = "bpf_array",

	.map_btf_id = &array_of_maps_map_btf_id,

	.map_btf_id = &array_map_btf_ids[0],

};

kernel/bpf/bloom_filter.c

+3 −3
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/err.h>

#include <linux/jhash.h>

#include <linux/random.h>

#include <linux/btf_ids.h>



#define BLOOM_CREATE_FLAG_MASK \

	(BPF_F_NUMA_NODE | BPF_F_ZERO_SEED | BPF_F_ACCESS_MASK)
@@ -192,7 +193,7 @@ static int bloom_map_check_btf(const struct bpf_map *map, 
	return btf_type_is_void(key_type) ? 0 : -EINVAL;

}



static int bpf_bloom_map_btf_id;

BTF_ID_LIST_SINGLE(bpf_bloom_map_btf_ids, struct, bpf_bloom_filter)

const struct bpf_map_ops bloom_filter_map_ops = {

	.map_meta_equal = bpf_map_meta_equal,

	.map_alloc = bloom_map_alloc,
@@ -205,6 +206,5 @@ const struct bpf_map_ops bloom_filter_map_ops = { 
	.map_update_elem = bloom_map_update_elem,

	.map_delete_elem = bloom_map_delete_elem,

	.map_check_btf = bloom_map_check_btf,

	.map_btf_name = "bpf_bloom_filter",

	.map_btf_id = &bpf_bloom_map_btf_id,

	.map_btf_id = &bpf_bloom_map_btf_ids[0],

};

kernel/bpf/bpf_inode_storage.c

+3 −3
Original line number Diff line number Diff line
@@ -245,7 +245,8 @@ static void inode_storage_map_free(struct bpf_map *map) 
	bpf_local_storage_map_free(smap, NULL);

}



static int inode_storage_map_btf_id;

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,
@@ -256,8 +257,7 @@ 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_name = "bpf_local_storage_map",

	.map_btf_id = &inode_storage_map_btf_id,

	.map_btf_id = &inode_storage_map_btf_ids[0],

	.map_owner_storage_ptr = inode_storage_ptr,

};

kernel/bpf/bpf_struct_ops.c

+3 −3
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/seq_file.h>

#include <linux/refcount.h>

#include <linux/mutex.h>

#include <linux/btf_ids.h>



enum bpf_struct_ops_state {

	BPF_STRUCT_OPS_STATE_INIT,
@@ -612,7 +613,7 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr) 
	return map;

}



static int bpf_struct_ops_map_btf_id;

BTF_ID_LIST_SINGLE(bpf_struct_ops_map_btf_ids, struct, bpf_struct_ops_map)

const struct bpf_map_ops bpf_struct_ops_map_ops = {

	.map_alloc_check = bpf_struct_ops_map_alloc_check,

	.map_alloc = bpf_struct_ops_map_alloc,
@@ -622,8 +623,7 @@ const struct bpf_map_ops bpf_struct_ops_map_ops = { 
	.map_delete_elem = bpf_struct_ops_map_delete_elem,

	.map_update_elem = bpf_struct_ops_map_update_elem,

	.map_seq_show_elem = bpf_struct_ops_map_seq_show_elem,

	.map_btf_name = "bpf_struct_ops_map",

	.map_btf_id = &bpf_struct_ops_map_btf_id,

	.map_btf_id = &bpf_struct_ops_map_btf_ids[0],

};



/* "const void *" because some subsystem is