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skmsg: Update saved hooks only once

Only update psock->saved_* if psock->sk_proto has not been initialized yet. This allows us to get rid of tcp_bpf_reinit_sk_prot.

Lorenz Bauer committed 6 years ago

Commit 1a2e2011 parent 7b709732 files · +17 −19Browse files

Showing the changes to include/linux (1 of 2 files). Show all

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include/linux/skmsg.h+16−4
@@ -347,11 +347,23 @@ static inline void sk_psock_update_proto(struct sock *sk, · 346 unmodified lines
347 struct sk_psock *psock,347 struct sk_psock *psock,
348 struct proto *ops)348 struct proto *ops)
349{349{
350 psock->saved_unhash = sk->sk_prot->unhash;350 /* Initialize saved callbacks and original proto only once, since this
351 psock->saved_close = sk->sk_prot->close;351 * function may be called multiple times for a psock, e.g. when
352 psock->saved_write_space = sk->sk_write_space;352 * psock->progs.msg_parser is updated.
353 *
354 * Since we've not installed the new proto, psock is not yet in use and
355 * we can initialize it without synchronization.
356 */
357 if (!psock->sk_proto) {
358 struct proto *orig = READ_ONCE(sk->sk_prot);
359
360 psock->saved_unhash = orig->unhash;
361 psock->saved_close = orig->close;
362 psock->saved_write_space = sk->sk_write_space;
363
364 psock->sk_proto = orig;
365 }
353 366
354 psock->sk_proto = sk->sk_prot;
355 /* Pairs with lockless read in sk_clone_lock() */367 /* Pairs with lockless read in sk_clone_lock() */
356 WRITE_ONCE(sk->sk_prot, ops);368 WRITE_ONCE(sk->sk_prot, ops);
357}369}