Merge branch 'move-attach_type-into-bpf_link'

Tao Chen says:

====================
Move attach_type into bpf_link

Andrii suggested moving the attach_type into bpf_link, the previous discussion
is as follows:
https://lore.kernel.org/bpf/CAEf4BzY7TZRjxpCJM-+LYgEqe23YFj5Uv3isb7gat2-HU4OSng@mail.gmail.com

patch1 add attach_type in bpf_link, and pass it to bpf_link_init, which
will init the attach_type field.

patch2-7 remove the attach_type in struct bpf_xx_link, update the info
with bpf_link attach_type.

There are some functions finally call bpf_link_init but do not have bpf_attr
from user or do not need to init attach_type from user like bpf_raw_tracepoint_open,
now use prog->expected_attach_type to init attach_type.

bpf_struct_ops_map_update_elem
bpf_raw_tracepoint_open
bpf_struct_ops_test_run

Feedback of any kind is welcome, thanks.
====================

Link: https://patch.msgid.link/20250710032038.888700-1-chen.dylane@linux.dev
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

7 files changed, 55 insertions, 46 deletions

diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 303ab1f42d3a..0cbcae727079 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -552,7 +552,8 @@ int bpf_iter_link_attach(const union bpf_attr *attr, bpfptr_t uattr,
 	if (!link)
 		return -ENOMEM;
 
-	bpf_link_init(&link->link, BPF_LINK_TYPE_ITER, &bpf_iter_link_lops, prog);
+	bpf_link_init(&link->link, BPF_LINK_TYPE_ITER, &bpf_iter_link_lops, prog,
+		      attr->link_create.attach_type);
 	link->tinfo = tinfo;
 
 	err = bpf_link_prime(&link->link, &link_primer);
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 96113633e391..687a3e9c76f5 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -808,7 +808,7 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
 			goto reset_unlock;
 		}
 		bpf_link_init(&link->link, BPF_LINK_TYPE_STRUCT_OPS,
-			      &bpf_struct_ops_link_lops, prog);
+			      &bpf_struct_ops_link_lops, prog, prog->expected_attach_type);
 		*plink++ = &link->link;
 
 		ksym = kzalloc(sizeof(*ksym), GFP_USER);
@@ -1351,7 +1351,8 @@ int bpf_struct_ops_link_create(union bpf_attr *attr)
 		err = -ENOMEM;
 		goto err_out;
 	}
-	bpf_link_init(&link->link, BPF_LINK_TYPE_STRUCT_OPS, &bpf_struct_ops_map_lops, NULL);
+	bpf_link_init(&link->link, BPF_LINK_TYPE_STRUCT_OPS, &bpf_struct_ops_map_lops, NULL,
+		      attr->link_create.attach_type);
 
 	err = bpf_link_prime(&link->link, &link_primer);
 	if (err)
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index cd220e861d67..72c8b50dca0a 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -867,7 +867,7 @@ static int __cgroup_bpf_attach(struct cgroup *cgrp,
 	cgrp->bpf.flags[atype] = saved_flags;
 
 	if (type == BPF_LSM_CGROUP) {
-		err = bpf_trampoline_link_cgroup_shim(new_prog, atype);
+		err = bpf_trampoline_link_cgroup_shim(new_prog, atype, type);
 		if (err)
 			goto cleanup;
 	}
@@ -984,7 +984,7 @@ static int __cgroup_bpf_replace(struct cgroup *cgrp,
 	struct hlist_head *progs;
 	bool found = false;
 
-	atype = bpf_cgroup_atype_find(link->type, new_prog->aux->attach_btf_id);
+	atype = bpf_cgroup_atype_find(link->link.attach_type, new_prog->aux->attach_btf_id);
 	if (atype < 0)
 		return -EINVAL;
 
@@ -1396,8 +1396,8 @@ static void bpf_cgroup_link_release(struct bpf_link *link)
 	}
 
 	WARN_ON(__cgroup_bpf_detach(cg_link->cgroup, NULL, cg_link,
-				    cg_link->type, 0));
-	if (cg_link->type == BPF_LSM_CGROUP)
+				    link->attach_type, 0));
+	if (link->attach_type == BPF_LSM_CGROUP)
 		bpf_trampoline_unlink_cgroup_shim(cg_link->link.prog);
 
 	cg = cg_link->cgroup;
@@ -1439,7 +1439,7 @@ static void bpf_cgroup_link_show_fdinfo(const struct bpf_link *link,
 		   "cgroup_id:\t%llu\n"
 		   "attach_type:\t%d\n",
 		   cg_id,
-		   cg_link->type);
+		   link->attach_type);
 }
 
 static int bpf_cgroup_link_fill_link_info(const struct bpf_link *link,
@@ -1455,7 +1455,7 @@ static int bpf_cgroup_link_fill_link_info(const struct bpf_link *link,
 	cgroup_unlock();
 
 	info->cgroup.cgroup_id = cg_id;
-	info->cgroup.attach_type = cg_link->type;
+	info->cgroup.attach_type = link->attach_type;
 	return 0;
 }
 
@@ -1495,9 +1495,8 @@ int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 		goto out_put_cgroup;
 	}
 	bpf_link_init(&link->link, BPF_LINK_TYPE_CGROUP, &bpf_cgroup_link_lops,
-		      prog);
+		      prog, attr->link_create.attach_type);
 	link->cgroup = cgrp;
-	link->type = attr->link_create.attach_type;
 
 	err = bpf_link_prime(&link->link, &link_primer);
 	if (err) {
@@ -1506,7 +1505,7 @@ int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 	}
 
 	err = cgroup_bpf_attach(cgrp, NULL, NULL, link,
-				link->type, BPF_F_ALLOW_MULTI | attr->link_create.flags,
+				link->link.attach_type, BPF_F_ALLOW_MULTI | attr->link_create.flags,
 				attr->link_create.cgroup.relative_fd,
 				attr->link_create.cgroup.expected_revision);
 	if (err) {
diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c
index 868cc2c43899..8e88201c98bf 100644
--- a/kernel/bpf/net_namespace.c
+++ b/kernel/bpf/net_namespace.c
@@ -11,8 +11,6 @@
 
 struct bpf_netns_link {
 	struct bpf_link	link;
-	enum bpf_attach_type type;
-	enum netns_bpf_attach_type netns_type;
 
 	/* We don't hold a ref to net in order to auto-detach the link
 	 * when netns is going away. Instead we rely on pernet
@@ -21,6 +19,7 @@ struct bpf_netns_link {
 	 */
 	struct net *net;
 	struct list_head node; /* node in list of links attached to net */
+	enum netns_bpf_attach_type netns_type;
 };
 
 /* Protects updates to netns_bpf */
@@ -216,7 +215,7 @@ static int bpf_netns_link_fill_info(const struct bpf_link *link,
 	mutex_unlock(&netns_bpf_mutex);
 
 	info->netns.netns_ino = inum;
-	info->netns.attach_type = net_link->type;
+	info->netns.attach_type = link->attach_type;
 	return 0;
 }
 
@@ -230,7 +229,7 @@ static void bpf_netns_link_show_fdinfo(const struct bpf_link *link,
 		   "netns_ino:\t%u\n"
 		   "attach_type:\t%u\n",
 		   info.netns.netns_ino,
-		   info.netns.attach_type);
+		   link->attach_type);
 }
 
 static const struct bpf_link_ops bpf_netns_link_ops = {
@@ -501,9 +500,8 @@ int netns_bpf_link_create(const union bpf_attr *attr, struct bpf_prog *prog)
 		goto out_put_net;
 	}
 	bpf_link_init(&net_link->link, BPF_LINK_TYPE_NETNS,
-		      &bpf_netns_link_ops, prog);
+		      &bpf_netns_link_ops, prog, type);
 	net_link->net = net;
-	net_link->type = type;
 	net_link->netns_type = netns_type;
 
 	err = bpf_link_prime(&net_link->link, &link_primer);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 3f36bfe13266..1a26d17536be 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3069,7 +3069,7 @@ static int bpf_obj_get(const union bpf_attr *attr)
  */
 void bpf_link_init_sleepable(struct bpf_link *link, enum bpf_link_type type,
 			     const struct bpf_link_ops *ops, struct bpf_prog *prog,
-			     bool sleepable)
+			     enum bpf_attach_type attach_type, bool sleepable)
 {
 	WARN_ON(ops->dealloc && ops->dealloc_deferred);
 	atomic64_set(&link->refcnt, 1);
@@ -3078,12 +3078,14 @@ void bpf_link_init_sleepable(struct bpf_link *link, enum bpf_link_type type,
 	link->id = 0;
 	link->ops = ops;
 	link->prog = prog;
+	link->attach_type = attach_type;
 }
 
 void bpf_link_init(struct bpf_link *link, enum bpf_link_type type,
-		   const struct bpf_link_ops *ops, struct bpf_prog *prog)
+		   const struct bpf_link_ops *ops, struct bpf_prog *prog,
+		   enum bpf_attach_type attach_type)
 {
-	bpf_link_init_sleepable(link, type, ops, prog, false);
+	bpf_link_init_sleepable(link, type, ops, prog, attach_type, false);
 }
 
 static void bpf_link_free_id(int id)
@@ -3412,7 +3414,7 @@ static void bpf_tracing_link_show_fdinfo(const struct bpf_link *link,
 		   "target_obj_id:\t%u\n"
 		   "target_btf_id:\t%u\n"
 		   "cookie:\t%llu\n",
-		   tr_link->attach_type,
+		   link->attach_type,
 		   target_obj_id,
 		   target_btf_id,
 		   tr_link->link.cookie);
@@ -3424,7 +3426,7 @@ static int bpf_tracing_link_fill_link_info(const struct bpf_link *link,
 	struct bpf_tracing_link *tr_link =
 		container_of(link, struct bpf_tracing_link, link.link);
 
-	info->tracing.attach_type = tr_link->attach_type;
+	info->tracing.attach_type = link->attach_type;
 	info->tracing.cookie = tr_link->link.cookie;
 	bpf_trampoline_unpack_key(tr_link->trampoline->key,
 				  &info->tracing.target_obj_id,
@@ -3443,7 +3445,8 @@ static const struct bpf_link_ops bpf_tracing_link_lops = {
 static int bpf_tracing_prog_attach(struct bpf_prog *prog,
 				   int tgt_prog_fd,
 				   u32 btf_id,
-				   u64 bpf_cookie)
+				   u64 bpf_cookie,
+				   enum bpf_attach_type attach_type)
 {
 	struct bpf_link_primer link_primer;
 	struct bpf_prog *tgt_prog = NULL;
@@ -3511,8 +3514,8 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
 		goto out_put_prog;
 	}
 	bpf_link_init(&link->link.link, BPF_LINK_TYPE_TRACING,
-		      &bpf_tracing_link_lops, prog);
-	link->attach_type = prog->expected_attach_type;
+		      &bpf_tracing_link_lops, prog, attach_type);
+
 	link->link.cookie = bpf_cookie;
 
 	mutex_lock(&prog->aux->dst_mutex);
@@ -4049,7 +4052,8 @@ static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *pro
 		err = -ENOMEM;
 		goto out_put_file;
 	}
-	bpf_link_init(&link->link, BPF_LINK_TYPE_PERF_EVENT, &bpf_perf_link_lops, prog);
+	bpf_link_init(&link->link, BPF_LINK_TYPE_PERF_EVENT, &bpf_perf_link_lops, prog,
+		      attr->link_create.attach_type);
 	link->perf_file = perf_file;
 
 	err = bpf_link_prime(&link->link, &link_primer);
@@ -4081,7 +4085,8 @@ static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *pro
 #endif /* CONFIG_PERF_EVENTS */
 
 static int bpf_raw_tp_link_attach(struct bpf_prog *prog,
-				  const char __user *user_tp_name, u64 cookie)
+				  const char __user *user_tp_name, u64 cookie,
+				  enum bpf_attach_type attach_type)
 {
 	struct bpf_link_primer link_primer;
 	struct bpf_raw_tp_link *link;
@@ -4104,7 +4109,7 @@ static int bpf_raw_tp_link_attach(struct bpf_prog *prog,
 			tp_name = prog->aux->attach_func_name;
 			break;
 		}
-		return bpf_tracing_prog_attach(prog, 0, 0, 0);
+		return bpf_tracing_prog_attach(prog, 0, 0, 0, attach_type);
 	case BPF_PROG_TYPE_RAW_TRACEPOINT:
 	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
 		if (strncpy_from_user(buf, user_tp_name, sizeof(buf) - 1) < 0)
@@ -4126,7 +4131,7 @@ static int bpf_raw_tp_link_attach(struct bpf_prog *prog,
 		goto out_put_btp;
 	}
 	bpf_link_init_sleepable(&link->link, BPF_LINK_TYPE_RAW_TRACEPOINT,
-				&bpf_raw_tp_link_lops, prog,
+				&bpf_raw_tp_link_lops, prog, attach_type,
 				tracepoint_is_faultable(btp->tp));
 	link->btp = btp;
 	link->cookie = cookie;
@@ -4168,7 +4173,7 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
 
 	tp_name = u64_to_user_ptr(attr->raw_tracepoint.name);
 	cookie = attr->raw_tracepoint.cookie;
-	fd = bpf_raw_tp_link_attach(prog, tp_name, cookie);
+	fd = bpf_raw_tp_link_attach(prog, tp_name, cookie, prog->expected_attach_type);
 	if (fd < 0)
 		bpf_prog_put(prog);
 	return fd;
@@ -5525,7 +5530,8 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
 		ret = bpf_tracing_prog_attach(prog,
 					      attr->link_create.target_fd,
 					      attr->link_create.target_btf_id,
-					      attr->link_create.tracing.cookie);
+					      attr->link_create.tracing.cookie,
+					      attr->link_create.attach_type);
 		break;
 	case BPF_PROG_TYPE_LSM:
 	case BPF_PROG_TYPE_TRACING:
@@ -5534,7 +5540,8 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
 			goto out;
 		}
 		if (prog->expected_attach_type == BPF_TRACE_RAW_TP)
-			ret = bpf_raw_tp_link_attach(prog, NULL, attr->link_create.tracing.cookie);
+			ret = bpf_raw_tp_link_attach(prog, NULL, attr->link_create.tracing.cookie,
+						     attr->link_create.attach_type);
 		else if (prog->expected_attach_type == BPF_TRACE_ITER)
 			ret = bpf_iter_link_attach(attr, uattr, prog);
 		else if (prog->expected_attach_type == BPF_LSM_CGROUP)
@@ -5543,7 +5550,8 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
 			ret = bpf_tracing_prog_attach(prog,
 						      attr->link_create.target_fd,
 						      attr->link_create.target_btf_id,
-						      attr->link_create.tracing.cookie);
+						      attr->link_create.tracing.cookie,
+						      attr->link_create.attach_type);
 		break;
 	case BPF_PROG_TYPE_FLOW_DISSECTOR:
 	case BPF_PROG_TYPE_SK_LOOKUP:
diff --git a/kernel/bpf/tcx.c b/kernel/bpf/tcx.c
index 2e4885e7781f..efd987ea6872 100644
--- a/kernel/bpf/tcx.c
+++ b/kernel/bpf/tcx.c
@@ -142,7 +142,7 @@ static int tcx_link_prog_attach(struct bpf_link *link, u32 flags, u32 id_or_fd,
 				u64 revision)
 {
 	struct tcx_link *tcx = tcx_link(link);
-	bool created, ingress = tcx->location == BPF_TCX_INGRESS;
+	bool created, ingress = link->attach_type == BPF_TCX_INGRESS;
 	struct bpf_mprog_entry *entry, *entry_new;
 	struct net_device *dev = tcx->dev;
 	int ret;
@@ -169,7 +169,7 @@ static int tcx_link_prog_attach(struct bpf_link *link, u32 flags, u32 id_or_fd,
 static void tcx_link_release(struct bpf_link *link)
 {
 	struct tcx_link *tcx = tcx_link(link);
-	bool ingress = tcx->location == BPF_TCX_INGRESS;
+	bool ingress = link->attach_type == BPF_TCX_INGRESS;
 	struct bpf_mprog_entry *entry, *entry_new;
 	struct net_device *dev;
 	int ret = 0;
@@ -204,7 +204,7 @@ static int tcx_link_update(struct bpf_link *link, struct bpf_prog *nprog,
 			   struct bpf_prog *oprog)
 {
 	struct tcx_link *tcx = tcx_link(link);
-	bool ingress = tcx->location == BPF_TCX_INGRESS;
+	bool ingress = link->attach_type == BPF_TCX_INGRESS;
 	struct bpf_mprog_entry *entry, *entry_new;
 	struct net_device *dev;
 	int ret = 0;
@@ -260,8 +260,8 @@ static void tcx_link_fdinfo(const struct bpf_link *link, struct seq_file *seq)
 
 	seq_printf(seq, "ifindex:\t%u\n", ifindex);
 	seq_printf(seq, "attach_type:\t%u (%s)\n",
-		   tcx->location,
-		   tcx->location == BPF_TCX_INGRESS ? "ingress" : "egress");
+		   link->attach_type,
+		   link->attach_type == BPF_TCX_INGRESS ? "ingress" : "egress");
 }
 
 static int tcx_link_fill_info(const struct bpf_link *link,
@@ -276,7 +276,7 @@ static int tcx_link_fill_info(const struct bpf_link *link,
 	rtnl_unlock();
 
 	info->tcx.ifindex = ifindex;
-	info->tcx.attach_type = tcx->location;
+	info->tcx.attach_type = link->attach_type;
 	return 0;
 }
 
@@ -301,8 +301,8 @@ static int tcx_link_init(struct tcx_link *tcx,
 			 struct net_device *dev,
 			 struct bpf_prog *prog)
 {
-	bpf_link_init(&tcx->link, BPF_LINK_TYPE_TCX, &tcx_link_lops, prog);
-	tcx->location = attr->link_create.attach_type;
+	bpf_link_init(&tcx->link, BPF_LINK_TYPE_TCX, &tcx_link_lops, prog,
+		      attr->link_create.attach_type);
 	tcx->dev = dev;
 	return bpf_link_prime(&tcx->link, link_primer);
 }
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index b1e358c16eeb..0e364614c3a2 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -674,7 +674,8 @@ static const struct bpf_link_ops bpf_shim_tramp_link_lops = {
 
 static struct bpf_shim_tramp_link *cgroup_shim_alloc(const struct bpf_prog *prog,
 						     bpf_func_t bpf_func,
-						     int cgroup_atype)
+						     int cgroup_atype,
+						     enum bpf_attach_type attach_type)
 {
 	struct bpf_shim_tramp_link *shim_link = NULL;
 	struct bpf_prog *p;
@@ -701,7 +702,7 @@ static struct bpf_shim_tramp_link *cgroup_shim_alloc(const struct bpf_prog *prog
 	p->expected_attach_type = BPF_LSM_MAC;
 	bpf_prog_inc(p);
 	bpf_link_init(&shim_link->link.link, BPF_LINK_TYPE_UNSPEC,
-		      &bpf_shim_tramp_link_lops, p);
+		      &bpf_shim_tramp_link_lops, p, attach_type);
 	bpf_cgroup_atype_get(p->aux->attach_btf_id, cgroup_atype);
 
 	return shim_link;
@@ -726,7 +727,8 @@ static struct bpf_shim_tramp_link *cgroup_shim_find(struct bpf_trampoline *tr,
 }
 
 int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog,
-				    int cgroup_atype)
+				    int cgroup_atype,
+				    enum bpf_attach_type attach_type)
 {
 	struct bpf_shim_tramp_link *shim_link = NULL;
 	struct bpf_attach_target_info tgt_info = {};
@@ -763,7 +765,7 @@ int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog,
 
 	/* Allocate and install new shim. */
 
-	shim_link = cgroup_shim_alloc(prog, bpf_func, cgroup_atype);
+	shim_link = cgroup_shim_alloc(prog, bpf_func, cgroup_atype, attach_type);
 	if (!shim_link) {
 		err = -ENOMEM;
 		goto err;