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/[email protected]
Signed-off-by: Andrii Nakryiko <[email protected]>

Author: anakryiko

drivers/net/netkit.c

@@ -32,7 +32,6 @@ struct netkit {
 struct netkit_link {
 	struct bpf_link link;
 	struct net_device *dev;
-	u32 location;
 };
 
 static __always_inline int
@@ -733,8 +732,8 @@ static void netkit_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",
-		   nkl->location,
-		   nkl->location == BPF_NETKIT_PRIMARY ? "primary" : "peer");
+		   link->attach_type,
+		   link->attach_type == BPF_NETKIT_PRIMARY ? "primary" : "peer");
 }
 
 static int netkit_link_fill_info(const struct bpf_link *link,
@@ -749,7 +748,7 @@ static int netkit_link_fill_info(const struct bpf_link *link,
 	rtnl_unlock();
 
 	info->netkit.ifindex = ifindex;
-	info->netkit.attach_type = nkl->location;
+	info->netkit.attach_type = link->attach_type;
 	return 0;
 }
 
@@ -775,8 +774,7 @@ static int netkit_link_init(struct netkit_link *nkl,
 			    struct bpf_prog *prog)
 {
 	bpf_link_init(&nkl->link, BPF_LINK_TYPE_NETKIT,
-		      &netkit_link_lops, prog);
-	nkl->location = attr->link_create.attach_type;
+		      &netkit_link_lops, prog, attr->link_create.attach_type);
 	nkl->dev = dev;
 	return bpf_link_prime(&nkl->link, link_primer);
 }

include/linux/bpf-cgroup.h

@@ -103,7 +103,6 @@ struct bpf_cgroup_storage {
 struct bpf_cgroup_link {
 	struct bpf_link link;
 	struct cgroup *cgroup;
-	enum bpf_attach_type type;
 };
 
 struct bpf_prog_list {

include/linux/bpf.h

@@ -1729,19 +1729,22 @@ struct bpf_link {
 	enum bpf_link_type type;
 	const struct bpf_link_ops *ops;
 	struct bpf_prog *prog;
-	/* whether BPF link itself has "sleepable" semantics, which can differ
-	 * from underlying BPF program having a "sleepable" semantics, as BPF
-	 * link's semantics is determined by target attach hook
-	 */
-	bool sleepable;
+
 	u32 flags;
+	enum bpf_attach_type attach_type;
+
 	/* rcu is used before freeing, work can be used to schedule that
 	 * RCU-based freeing before that, so they never overlap
 	 */
 	union {
 		struct rcu_head rcu;
 		struct work_struct work;
 	};
+	/* whether BPF link itself has "sleepable" semantics, which can differ
+	 * from underlying BPF program having a "sleepable" semantics, as BPF
+	 * link's semantics is determined by target attach hook
+	 */
+	bool sleepable;
 };
 
 struct bpf_link_ops {
@@ -1781,7 +1784,6 @@ struct bpf_shim_tramp_link {
 
 struct bpf_tracing_link {
 	struct bpf_tramp_link link;
-	enum bpf_attach_type attach_type;
 	struct bpf_trampoline *trampoline;
 	struct bpf_prog *tgt_prog;
 };
@@ -2034,11 +2036,13 @@ int bpf_prog_ctx_arg_info_init(struct bpf_prog *prog,
 
 #if defined(CONFIG_CGROUP_BPF) && defined(CONFIG_BPF_LSM)
 int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog,
-				    int cgroup_atype);
+				    int cgroup_atype,
+				    enum bpf_attach_type attach_type);
 void bpf_trampoline_unlink_cgroup_shim(struct bpf_prog *prog);
 #else
 static inline int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog,
-						  int cgroup_atype)
+						  int cgroup_atype,
+						  enum bpf_attach_type attach_type)
 {
 	return -EOPNOTSUPP;
 }
@@ -2528,10 +2532,11 @@ int bpf_map_new_fd(struct bpf_map *map, int flags);
 int bpf_prog_new_fd(struct bpf_prog *prog);
 
 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);
 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);
 int bpf_link_prime(struct bpf_link *link, struct bpf_link_primer *primer);
 int bpf_link_settle(struct bpf_link_primer *primer);
 void bpf_link_cleanup(struct bpf_link_primer *primer);
@@ -2883,13 +2888,13 @@ bpf_prog_inc_not_zero(struct bpf_prog *prog)
 
 static inline void bpf_link_init(struct bpf_link *link, enum bpf_link_type type,
 				 const struct bpf_link_ops *ops,
-				 struct bpf_prog *prog)
+				 struct bpf_prog *prog, enum bpf_attach_type attach_type)
 {
 }
 
 static inline 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)
 {
 }
 

include/net/tcx.h

@@ -20,7 +20,6 @@ struct tcx_entry {
 struct tcx_link {
 	struct bpf_link link;
 	struct net_device *dev;
-	u32 location;
 };
 
 static inline void tcx_set_ingress(struct sk_buff *skb, bool ingress)

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);

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)

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) {

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);