kernel/printk/nbcon.c

132  * @cur:	Old/expected state
135  * Return: True on success. False on fail and @cur is updated.
137 static inline bool nbcon_state_try_cmpxchg(struct console *con, struct nbcon_state *cur,
140 	return atomic_try_cmpxchg(&ACCESS_PRIVATE(con, nbcon_state), &cur->atom, new->atom);
207  * @cur:	The current console state
212  * Return:	0 on success. Otherwise, an error code on failure. Also @cur
227 					    struct nbcon_state *cur)
237 		if (ctxt->prio <= cur->prio || ctxt->prio <= cur->req_prio)
240 		if (cur->unsafe)
247 		WARN_ON_ONCE(cur->unsafe_takeover);
249 		new.atom = cur->atom;
252 		new.unsafe	= cur->unsafe_takeover;
255 	} while (!nbcon_state_try_cmpxchg(con, cur, &new));
260 static bool nbcon_waiter_matches(struct nbcon_state *cur, int expected_prio)
279 	return (cur->req_prio == expected_prio);
286  * @cur:	The current console state
292  * Return:	0 on success and @cur is updated to the new console state.
307 					       struct nbcon_state *cur)
321 	if (!nbcon_waiter_matches(cur, ctxt->prio))
325 	if (cur->prio != NBCON_PRIO_NONE)
332 	WARN_ON_ONCE(cur->unsafe);
334 	new.atom = cur->atom;
337 	new.unsafe	= cur->unsafe_takeover;
340 	if (!nbcon_state_try_cmpxchg(con, cur, &new)) {
345 		WARN_ON_ONCE(nbcon_waiter_matches(cur, ctxt->prio));
356  * @cur:	The current console state
370  * Return:	0 on success. Otherwise, an error code on failure. Also @cur
386  *	-EAGAIN:	@cur has changed when creating the handover request.
390 					      struct nbcon_state *cur)
402 	WARN_ON_ONCE(ctxt->prio <= cur->prio || ctxt->prio <= cur->req_prio);
403 	WARN_ON_ONCE(!cur->unsafe);
406 	if (cur->cpu == cpu)
413 	if (cur->unsafe_takeover)
424 	new.atom = cur->atom;
426 	if (!nbcon_state_try_cmpxchg(con, cur, &new))
429 	cur->atom = new.atom;
434 		request_err = nbcon_context_try_acquire_requested(ctxt, cur);
448 		nbcon_state_read(con, cur);
458 		if (!nbcon_waiter_matches(cur, ctxt->prio))
462 		new.atom = cur->atom;
464 		if (nbcon_state_try_cmpxchg(con, cur, &new)) {
469 			cur->atom = new.atom;
477 	} while (nbcon_context_try_acquire_requested(ctxt, cur));
486  * @cur:	The current console state
496 					     struct nbcon_state *cur)
513 	WARN_ON_ONCE(ctxt->prio <= cur->prio || ctxt->prio <= cur->req_prio);
514 	WARN_ON_ONCE(cur->unsafe != true);
517 		new.atom = cur->atom;
520 		new.unsafe		|= cur->unsafe_takeover;
521 		new.unsafe_takeover	|= cur->unsafe;
523 	} while (!nbcon_state_try_cmpxchg(con, cur, &new));
546 	struct nbcon_state cur;
549 	nbcon_state_read(con, &cur);
551 	err = nbcon_context_try_acquire_direct(ctxt, &cur);
555 	err = nbcon_context_try_acquire_handover(ctxt, &cur);
561 	err = nbcon_context_try_acquire_hostile(ctxt, &cur);
580 static bool nbcon_owner_matches(struct nbcon_state *cur, int expected_cpu,
591 	if (cur->prio != expected_prio)
594 	if (cur->cpu != expected_cpu)
608 	struct nbcon_state cur;
611 	nbcon_state_read(con, &cur);
614 		if (!nbcon_owner_matches(&cur, cpu, ctxt->prio))
617 		new.atom = cur.atom;
624 		new.unsafe |= cur.unsafe_takeover;
626 	} while (!nbcon_state_try_cmpxchg(con, &cur, &new));
634  * @cur:	The current console state
657 static bool nbcon_context_can_proceed(struct nbcon_context *ctxt, struct nbcon_state *cur)
662 	if (!nbcon_owner_matches(cur, cpu, ctxt->prio))
666 	if (cur->req_prio == NBCON_PRIO_NONE)
675 	if (cur->unsafe)
679 	WARN_ON_ONCE(cur->req_prio <= cur->prio);
729 	struct nbcon_state cur;
731 	nbcon_state_read(con, &cur);
733 	return nbcon_context_can_proceed(ctxt, &cur);
762 	struct nbcon_state cur;
765 	nbcon_state_read(con, &cur);
772 		if (!unsafe && cur.unsafe_takeover)
775 		if (!nbcon_context_can_proceed(ctxt, &cur))
778 		new.atom = cur.atom;
780 	} while (!nbcon_state_try_cmpxchg(con, &cur, &new));
782 	cur.atom = new.atom;
784 	return nbcon_context_can_proceed(ctxt, &cur);
853 	struct nbcon_state cur;
891 	nbcon_state_read(con, &cur);
892 	wctxt->unsafe_takeover = cur.unsafe_takeover;