Date: Sun, 22 Aug 2021 00:29:18 GMT From: Alexander Motin <mav@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 0417804260fd - stable/12 - kbdmux(4): Make callout handler mpsafe. Message-ID: <202108220029.17M0TIQK033732@gitrepo.freebsd.org>
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The branch stable/12 has been updated by mav: URL: https://cgit.FreeBSD.org/src/commit/?id=0417804260fd61ab47424632c26532d6ce2fed14 commit 0417804260fd61ab47424632c26532d6ce2fed14 Author: Alexander Motin <mav@FreeBSD.org> AuthorDate: 2021-08-08 22:19:08 +0000 Commit: Alexander Motin <mav@FreeBSD.org> CommitDate: 2021-08-22 00:27:58 +0000 kbdmux(4): Make callout handler mpsafe. Both callout and taskqueue now have drain() routines not requiring external locking. It allows to remove TASK flag and manual drain, so the only thing remaining for lock to protect inside the callout handler is ks_inq_length zero comparison, that can be lockless. MFC after: 2 weeks (cherry picked from commit e5018628e76a27e0f61ca03e2aa2247b3c62a158) --- sys/dev/kbdmux/kbdmux.c | 61 ++++++++----------------------------------------- 1 file changed, 10 insertions(+), 51 deletions(-) diff --git a/sys/dev/kbdmux/kbdmux.c b/sys/dev/kbdmux/kbdmux.c index 5c24db23da55..8fb220b898ce 100644 --- a/sys/dev/kbdmux/kbdmux.c +++ b/sys/dev/kbdmux/kbdmux.c @@ -105,12 +105,6 @@ MALLOC_DEFINE(M_KBDMUX, KEYBOARD_NAME, "Keyboard multiplexor"); mtx_unlock(&(s)->ks_lock) #define KBDMUX_LOCK_ASSERT(s, w) \ mtx_assert(&(s)->ks_lock, (w)) -#define KBDMUX_SLEEP(s, f, d, t) \ - msleep(&(s)->f, &(s)->ks_lock, PCATCH | (PZERO + 1), (d), (t)) -#define KBDMUX_CALLOUT_INIT(s) \ - callout_init_mtx(&(s)->ks_timo, &(s)->ks_lock, 0) -#define KBDMUX_QUEUE_INTR(s) \ - taskqueue_enqueue(taskqueue_swi_giant, &(s)->ks_task) #else #define KBDMUX_LOCK_DECL_GLOBAL @@ -124,12 +118,6 @@ MALLOC_DEFINE(M_KBDMUX, KEYBOARD_NAME, "Keyboard multiplexor"); #define KBDMUX_LOCK_ASSERT(s, w) -#define KBDMUX_SLEEP(s, f, d, t) \ - tsleep(&(s)->f, PCATCH | (PZERO + 1), (d), (t)) -#define KBDMUX_CALLOUT_INIT(s) \ - callout_init(&(s)->ks_timo, 0) -#define KBDMUX_QUEUE_INTR(s) \ - taskqueue_enqueue(taskqueue_swi_giant, &(s)->ks_task) #endif /* not yet */ /* @@ -157,7 +145,6 @@ struct kbdmux_state int ks_flags; /* flags */ #define COMPOSE (1 << 0) /* compose char flag */ -#define TASK (1 << 2) /* interrupt task queued */ int ks_polling; /* poll nesting count */ int ks_mode; /* K_XLATE, K_RAW, K_CODE */ @@ -223,16 +210,8 @@ void kbdmux_kbd_intr(void *xkbd, int pending) { keyboard_t *kbd = (keyboard_t *) xkbd; - kbdmux_state_t *state = (kbdmux_state_t *) kbd->kb_data; kbdd_intr(kbd, NULL); - - KBDMUX_LOCK(state); - - state->ks_flags &= ~TASK; - wakeup(&state->ks_task); - - KBDMUX_UNLOCK(state); } /* @@ -243,23 +222,12 @@ kbdmux_kbd_intr_timo(void *xstate) { kbdmux_state_t *state = (kbdmux_state_t *) xstate; - KBDMUX_LOCK_ASSERT(state, MA_OWNED); - - if (callout_pending(&state->ks_timo)) - return; /* callout was reset */ - - if (!callout_active(&state->ks_timo)) - return; /* callout was stopped */ - - callout_deactivate(&state->ks_timo); - /* queue interrupt task if needed */ - if (state->ks_inq_length > 0 && !(state->ks_flags & TASK) && - KBDMUX_QUEUE_INTR(state) == 0) - state->ks_flags |= TASK; + if (state->ks_inq_length > 0) + taskqueue_enqueue(taskqueue_swi_giant, &state->ks_task); /* re-schedule timeout */ - callout_reset(&state->ks_timo, TICKS, kbdmux_kbd_intr_timo, state); + callout_schedule(&state->ks_timo, TICKS); } /* @@ -299,9 +267,8 @@ kbdmux_kbd_event(keyboard_t *kbd, int event, void *arg) } /* queue interrupt task if needed */ - if (state->ks_inq_length > 0 && !(state->ks_flags & TASK) && - KBDMUX_QUEUE_INTR(state) == 0) - state->ks_flags |= TASK; + if (state->ks_inq_length > 0) + taskqueue_enqueue(taskqueue_swi_giant, &state->ks_task); KBDMUX_UNLOCK(state); } break; @@ -444,7 +411,7 @@ kbdmux_init(int unit, keyboard_t **kbdp, void *arg, int flags) KBDMUX_LOCK_INIT(state); TASK_INIT(&state->ks_task, 0, kbdmux_kbd_intr, (void *) kbd); - KBDMUX_CALLOUT_INIT(state); + callout_init(&state->ks_timo, 1); SLIST_INIT(&state->ks_kbds); } else if (KBD_IS_INITIALIZED(*kbdp) && KBD_IS_CONFIGURED(*kbdp)) { return (0); @@ -521,9 +488,7 @@ kbdmux_init(int unit, keyboard_t **kbdp, void *arg, int flags) KBD_CONFIG_DONE(kbd); - KBDMUX_LOCK(state); callout_reset(&state->ks_timo, TICKS, kbdmux_kbd_intr_timo, state); - KBDMUX_UNLOCK(state); } return (0); @@ -555,16 +520,8 @@ kbdmux_term(keyboard_t *kbd) kbdmux_state_t *state = (kbdmux_state_t *) kbd->kb_data; kbdmux_kbd_t *k; - KBDMUX_LOCK(state); - - /* kill callout */ - callout_stop(&state->ks_timo); - - /* wait for interrupt task */ - while (state->ks_flags & TASK) - KBDMUX_SLEEP(state, ks_task, "kbdmuxc", 0); - /* release all keyboards from the mux */ + KBDMUX_LOCK(state); while ((k = SLIST_FIRST(&state->ks_kbds)) != NULL) { kbd_release(k->kbd, &k->kbd); SLIST_REMOVE_HEAD(&state->ks_kbds, next); @@ -573,9 +530,11 @@ kbdmux_term(keyboard_t *kbd) free(k, M_KBDMUX); } - KBDMUX_UNLOCK(state); + callout_drain(&state->ks_timo); + taskqueue_drain(taskqueue_swi_giant, &state->ks_task); + kbd_unregister(kbd); #ifdef EVDEV_SUPPORT
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