samples/bpf: load_bpf.c make callback fixup more flexible

Do this change before others start to use this callback.
Change map_perf_test_user.c which seems to be the only user.

This patch extends capabilities of commit 9fd63d05f3e8 ("bpf:
Allow bpf sample programs (*_user.c) to change bpf_map_def").

Give fixup callback access to struct bpf_map_data, instead of
only stuct bpf_map_def.  This add flexibility to allow userspace
to reassign the map file descriptor.  This is very useful when
wanting to share maps between several bpf programs.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index fedec29c7817d8e1b1d945ed179671980c53e1b6..74456b3eb89acb4671fcebaafc2ce7bd102b3ed3 100644 (file)
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -39,13 +39,6 @@ int event_fd[MAX_PROGS];
 int prog_cnt;
 int prog_array_fd = -1;
 
-/* Keeping relevant info on maps */
-struct bpf_map_data {
-       int fd;
-       char *name;
-       size_t elf_offset;
-       struct bpf_map_def def;
-};
 struct bpf_map_data map_data[MAX_MAPS];
 int map_data_count = 0;
 
@@ -202,8 +195,14 @@ static int load_maps(struct bpf_map_data *maps, int nr_maps,
        int i;
 
        for (i = 0; i < nr_maps; i++) {
-               if (fixup_map)
-                       fixup_map(&maps[i].def, maps[i].name, i);
+               if (fixup_map) {
+                       fixup_map(&maps[i], i);
+                       /* Allow userspace to assign map FD prior to creation */
+                       if (maps[i].fd != -1) {
+                               map_fd[i] = maps[i].fd;
+                               continue;
+                       }
+               }
 
                if (maps[i].def.type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
                    maps[i].def.type == BPF_MAP_TYPE_HASH_OF_MAPS) {

diff --git a/samples/bpf/bpf_load.h b/samples/bpf/bpf_load.h
index 05822f83173af928fb13bfb046cb5b2b728c68d1..4d4fd4678a64be0aee1b929acadb6ba99d61d554 100644 (file)
--- a/samples/bpf/bpf_load.h
+++ b/samples/bpf/bpf_load.h
@@ -15,8 +15,14 @@ struct bpf_map_def {
        unsigned int inner_map_idx;
 };
 
-typedef void (*fixup_map_cb)(struct bpf_map_def *map, const char *map_name,
-                            int idx);
+struct bpf_map_data {
+       int fd;
+       char *name;
+       size_t elf_offset;
+       struct bpf_map_def def;
+};
+
+typedef void (*fixup_map_cb)(struct bpf_map_data *map, int idx);
 
 extern int map_fd[MAX_MAPS];
 extern int prog_fd[MAX_PROGS];

diff --git a/samples/bpf/map_perf_test_user.c b/samples/bpf/map_perf_test_user.c
index 6ac778153315edcbde80780bd68fbf5e288b677f..1a8894b5ac5147c36833ffae500ddfbeb00277d1 100644 (file)
--- a/samples/bpf/map_perf_test_user.c
+++ b/samples/bpf/map_perf_test_user.c
@@ -320,21 +320,21 @@ static void fill_lpm_trie(void)
        assert(!r);
 }
 
-static void fixup_map(struct bpf_map_def *map, const char *name, int idx)
+static void fixup_map(struct bpf_map_data *map, int idx)
 {
        int i;
 
-       if (!strcmp("inner_lru_hash_map", name)) {
+       if (!strcmp("inner_lru_hash_map", map->name)) {
                inner_lru_hash_idx = idx;
-               inner_lru_hash_size = map->max_entries;
+               inner_lru_hash_size = map->def.max_entries;
        }
 
-       if (!strcmp("array_of_lru_hashs", name)) {
+       if (!strcmp("array_of_lru_hashs", map->name)) {
                if (inner_lru_hash_idx == -1) {
                        printf("inner_lru_hash_map must be defined before array_of_lru_hashs\n");
                        exit(1);
                }
-               map->inner_map_idx = inner_lru_hash_idx;
+               map->def.inner_map_idx = inner_lru_hash_idx;
                array_of_lru_hashs_idx = idx;
        }
 
@@ -345,9 +345,9 @@ static void fixup_map(struct bpf_map_def *map, const char *name, int idx)
 
        /* Only change the max_entries for the enabled test(s) */
        for (i = 0; i < NR_TESTS; i++) {
-               if (!strcmp(test_map_names[i], name) &&
+               if (!strcmp(test_map_names[i], map->name) &&
                    (check_test_flags(i))) {
-                       map->max_entries = num_map_entries;
+                       map->def.max_entries = num_map_entries;
                }
        }
 }