Commit 151b98d1 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

net: Add sk_clone(). 



sctp_accept() will use sk_clone_lock(), but it will be called
with the parent socket locked, and sctp_migrate() acquires the
child lock later.

Let's add no lock version of sk_clone_lock().

Note that lockdep complains if we simply use bh_lock_sock_nested().

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: default avatarXin Long <lucien.xin@gmail.com>
Link: https://patch.msgid.link/20251023231751.4168390-5-kuniyu@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent b7185792

include/net/sock.h

+6 −1
Original line number Diff line number Diff line
@@ -1822,7 +1822,12 @@ struct sock *sk_alloc(struct net *net, int family, gfp_t priority, 
void sk_free(struct sock *sk);

void sk_net_refcnt_upgrade(struct sock *sk);

void sk_destruct(struct sock *sk);

struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority);

struct sock *sk_clone(const struct sock *sk, const gfp_t priority, bool lock);



static inline struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)

{

	return sk_clone(sk, priority, true);

}



struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,

			     gfp_t priority);

net/core/sock.c

+16 −8
Original line number Diff line number Diff line
@@ -2462,13 +2462,16 @@ static void sk_init_common(struct sock *sk) 
}



/**

 *	sk_clone_lock - clone a socket, and lock its clone

 * sk_clone - clone a socket

 * @sk: the socket to clone

 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)

 * @lock: if true, lock the cloned sk

 *

 *	Caller must unlock socket even in error path (bh_unlock_sock(newsk))

 * If @lock is true, the clone is locked by bh_lock_sock(), and

 * caller must unlock socket even in error path by bh_unlock_sock().

 */

struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)

struct sock *sk_clone(const struct sock *sk, const gfp_t priority,

		      bool lock)

{

	struct proto *prot = READ_ONCE(sk->sk_prot);

	struct sk_filter *filter;
@@ -2497,9 +2500,13 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority) 
		__netns_tracker_alloc(sock_net(newsk), &newsk->ns_tracker,

				      false, priority);

	}



	sk_node_init(&newsk->sk_node);

	sock_lock_init(newsk);



	if (lock)

		bh_lock_sock(newsk);



	newsk->sk_backlog.head	= newsk->sk_backlog.tail = NULL;

	newsk->sk_backlog.len = 0;
@@ -2590,12 +2597,13 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority) 
	 * destructor and make plain sk_free()

	 */

	newsk->sk_destruct = NULL;

	if (lock)

		bh_unlock_sock(newsk);

	sk_free(newsk);

	newsk = NULL;

	goto out;

}

EXPORT_SYMBOL_GPL(sk_clone_lock);

EXPORT_SYMBOL_GPL(sk_clone);



static u32 sk_dst_gso_max_size(struct sock *sk, const struct net_device *dev)

{