bpf: Add LINK_DETACH for iter and perf links

73b11c2 introduced LINK_DETACH and implemented it for some link types,
like xdp, netns and others.

This patch implements LINK_DETACH for perf and iter links, re-using
existing link release handling code.

Signed-off-by: Florian Lehner <[email protected]>

Author: florianl

kernel/bpf/bpf_iter.c

@@ -397,6 +397,12 @@ static void bpf_iter_link_release(struct bpf_link *link)
 		iter_link->tinfo->reg_info->detach_target(&iter_link->aux);
 }
 
+static int bpf_iter_link_detach(struct bpf_link *link)
+{
+	bpf_iter_link_release(link);
+	return 0;
+}
+
 static void bpf_iter_link_dealloc(struct bpf_link *link)
 {
 	struct bpf_iter_link *iter_link =
@@ -490,6 +496,7 @@ static int bpf_iter_link_fill_link_info(const struct bpf_link *link,
 
 static const struct bpf_link_ops bpf_iter_link_lops = {
 	.release = bpf_iter_link_release,
+	.detach = bpf_iter_link_detach,
 	.dealloc = bpf_iter_link_dealloc,
 	.update_prog = bpf_iter_link_replace,
 	.show_fdinfo = bpf_iter_link_show_fdinfo,

kernel/bpf/syscall.c

@@ -3733,6 +3733,12 @@ static void bpf_perf_link_release(struct bpf_link *link)
 	fput(perf_link->perf_file);
 }
 
+static int bpf_perf_link_detach(struct bpf_link *link)
+{
+	bpf_perf_link_release(link);
+	return 0;
+}
+
 static void bpf_perf_link_dealloc(struct bpf_link *link)
 {
 	struct bpf_perf_link *perf_link = container_of(link, struct bpf_perf_link, link);
@@ -4027,6 +4033,7 @@ static void bpf_perf_link_show_fdinfo(const struct bpf_link *link,
 
 static const struct bpf_link_ops bpf_perf_link_lops = {
 	.release = bpf_perf_link_release,
+	.detach = bpf_perf_link_detach,
 	.dealloc = bpf_perf_link_dealloc,
 	.fill_link_info = bpf_perf_link_fill_link_info,
 	.show_fdinfo = bpf_perf_link_show_fdinfo,