On Fri, Oct 22, 2021 at 10:16 AM Quentin Monnet <quentin@xxxxxxxxxxxxx> wrote:
>
> In order to show PIDs and names for processes holding references to BPF
> programs, maps, links, or BTF objects, bpftool creates hash maps to
> store all relevant information. This commit is part of a set that
> transitions from the kernel's hash map implementation to the one coming
> with libbpf.
>
> The motivation is to make bpftool less dependent of kernel headers, to
> ease the path to a potential out-of-tree mirror, like libbpf has.
>
> This is the third and final step of the transition, in which we convert
> the hash maps used for storing the information about the processes
> holding references to BPF objects (programs, maps, links, BTF), and at
> last we drop the inclusion of tools/include/linux/hashtable.h.
>
> Note: Checkpatch complains about the use of __weak declarations, and the
> missing empty lines after the bunch of empty function declarations when
> compiling without the BPF skeletons (none of these were introduced in
> this patch). We want to keep things as they are, and the reports should
> be safe to ignore.
>
> Signed-off-by: Quentin Monnet <quentin@xxxxxxxxxxxxx>
> ---
> tools/bpf/bpftool/btf.c | 7 ++--
> tools/bpf/bpftool/link.c | 6 +--
> tools/bpf/bpftool/main.c | 5 ++-
> tools/bpf/bpftool/main.h | 17 +++-----
> tools/bpf/bpftool/map.c | 6 +--
> tools/bpf/bpftool/pids.c | 84 ++++++++++++++++++++++------------------
> tools/bpf/bpftool/prog.c | 6 +--
> 7 files changed, 67 insertions(+), 64 deletions(-)
>
[...]
> #include "pid_iter.skel.h"
>
> -static void add_ref(struct obj_refs_table *table, struct pid_iter_entry *e)
> +static void add_ref(struct hashmap *map, struct pid_iter_entry *e)
> {
> + struct hashmap_entry *entry;
> struct obj_refs *refs;
> struct obj_ref *ref;
> void *tmp;
> int i;
>
> - hash_for_each_possible(table->table, refs, node, e->id) {
> - if (refs->id != e->id)
> - continue;
> + hashmap__for_each_key_entry(map, entry, u32_as_hash_field(e->id)) {
> + refs = entry->value;
>
> for (i = 0; i < refs->ref_cnt; i++) {
> if (refs->refs[i].pid == e->pid)
> @@ -64,7 +66,6 @@ static void add_ref(struct obj_refs_table *table, struct pid_iter_entry *e)
> return;
> }
>
> - refs->id = e->id;
> refs->refs = malloc(sizeof(*refs->refs));
> if (!refs->refs) {
> free(refs);
> @@ -76,7 +77,7 @@ static void add_ref(struct obj_refs_table *table, struct pid_iter_entry *e)
> ref->pid = e->pid;
> memcpy(ref->comm, e->comm, sizeof(ref->comm));
> refs->ref_cnt = 1;
> - hash_add(table->table, &refs->node, e->id);
> + hashmap__append(map, u32_as_hash_field(e->id), refs);
here as well, can fail
> }
>
> static int __printf(2, 0)
> @@ -87,7 +88,7 @@ libbpf_print_none(__maybe_unused enum libbpf_print_level level,
> return 0;
> }
>
[...]
