Date: Fri, 24 May 2019 17:01:05 +0000 (UTC) From: Johannes Lundberg <johalun@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r348242 - in stable/12/sys/compat/linuxkpi/common: include/linux src Message-ID: <201905241701.x4OH15dA095138@repo.freebsd.org>
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Author: johalun Date: Fri May 24 17:01:05 2019 New Revision: 348242 URL: https://svnweb.freebsd.org/changeset/base/348242 Log: MFC r347852: LinuxKPI: Updates to tasklets for Linux 5.0. DRM drivers expect tasklets to have a counter for enable/disable calls. Also, add a few more tasklet locking functions. MFC also includes powerpc build fix from r347889. This patch is part of D19565 Reviewed by: hps Approved by: imp (mentor), hps Modified: stable/12/sys/compat/linuxkpi/common/include/linux/interrupt.h stable/12/sys/compat/linuxkpi/common/src/linux_tasklet.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/compat/linuxkpi/common/include/linux/interrupt.h ============================================================================== --- stable/12/sys/compat/linuxkpi/common/include/linux/interrupt.h Fri May 24 15:45:43 2019 (r348241) +++ stable/12/sys/compat/linuxkpi/common/include/linux/interrupt.h Fri May 24 17:01:05 2019 (r348242) @@ -189,11 +189,14 @@ typedef void tasklet_func_t(unsigned long); struct tasklet_struct { TAILQ_ENTRY(tasklet_struct) entry; tasklet_func_t *func; + /* Our "state" implementation is different. Avoid same name as Linux. */ + volatile u_int tasklet_state; + atomic_t count; unsigned long data; }; #define DECLARE_TASKLET(name, func, data) \ -struct tasklet_struct name = { { NULL, NULL }, func, data } +struct tasklet_struct name = { { NULL, NULL }, func, ATOMIC_INIT(0), data } #define tasklet_hi_schedule(t) tasklet_schedule(t) @@ -203,5 +206,8 @@ extern void tasklet_init(struct tasklet_struct *, task unsigned long data); extern void tasklet_enable(struct tasklet_struct *); extern void tasklet_disable(struct tasklet_struct *); +extern int tasklet_trylock(struct tasklet_struct *); +extern void tasklet_unlock(struct tasklet_struct *); +extern void tasklet_unlock_wait(struct tasklet_struct *ts); #endif /* _LINUX_INTERRUPT_H_ */ Modified: stable/12/sys/compat/linuxkpi/common/src/linux_tasklet.c ============================================================================== --- stable/12/sys/compat/linuxkpi/common/src/linux_tasklet.c Fri May 24 15:45:43 2019 (r348241) +++ stable/12/sys/compat/linuxkpi/common/src/linux_tasklet.c Fri May 24 17:01:05 2019 (r348242) @@ -41,20 +41,19 @@ __FBSDID("$FreeBSD$"); #define TASKLET_ST_BUSY 1 #define TASKLET_ST_EXEC 2 #define TASKLET_ST_LOOP 3 -#define TASKLET_ST_PAUSED 4 #define TASKLET_ST_CMPSET(ts, old, new) \ - atomic_cmpset_ptr((volatile uintptr_t *)&(ts)->entry.tqe_prev, old, new) + atomic_cmpset_int((volatile u_int *)&(ts)->tasklet_state, old, new) #define TASKLET_ST_SET(ts, new) \ - WRITE_ONCE(*(volatile uintptr_t *)&(ts)->entry.tqe_prev, new) + WRITE_ONCE(*(volatile u_int *)&(ts)->tasklet_state, new) #define TASKLET_ST_GET(ts) \ - READ_ONCE(*(volatile uintptr_t *)&(ts)->entry.tqe_prev) + READ_ONCE(*(volatile u_int *)&(ts)->tasklet_state) struct tasklet_worker { struct mtx mtx; - TAILQ_HEAD(, tasklet_struct) head; + TAILQ_HEAD(tasklet_list, tasklet_struct) head; struct grouptask gtask; } __aligned(CACHE_LINE_SIZE); @@ -68,25 +67,34 @@ tasklet_handler(void *arg) { struct tasklet_worker *tw = (struct tasklet_worker *)arg; struct tasklet_struct *ts; + struct tasklet_struct *last; linux_set_current(curthread); TASKLET_WORKER_LOCK(tw); + last = TAILQ_LAST(&tw->head, tasklet_list); while (1) { ts = TAILQ_FIRST(&tw->head); if (ts == NULL) break; TAILQ_REMOVE(&tw->head, ts, entry); - TASKLET_WORKER_UNLOCK(tw); - do { - /* reset executing state */ - TASKLET_ST_SET(ts, TASKLET_ST_EXEC); + if (!atomic_read(&ts->count)) { + TASKLET_WORKER_UNLOCK(tw); + do { + /* reset executing state */ + TASKLET_ST_SET(ts, TASKLET_ST_EXEC); - ts->func(ts->data); + ts->func(ts->data); - } while (TASKLET_ST_CMPSET(ts, TASKLET_ST_EXEC, TASKLET_ST_IDLE) == 0); - TASKLET_WORKER_LOCK(tw); + } while (TASKLET_ST_CMPSET(ts, TASKLET_ST_EXEC, + TASKLET_ST_IDLE) == 0); + TASKLET_WORKER_LOCK(tw); + } else { + TAILQ_INSERT_TAIL(&tw->head, ts, entry); + } + if (ts == last) + break; } TASKLET_WORKER_UNLOCK(tw); } @@ -140,6 +148,8 @@ tasklet_init(struct tasklet_struct *ts, ts->entry.tqe_next = NULL; ts->func = func; ts->data = data; + atomic_set_int(&ts->tasklet_state, TASKLET_ST_IDLE); + atomic_set(&ts->count, 0); } void @@ -158,6 +168,10 @@ void tasklet_schedule(struct tasklet_struct *ts) { + /* tasklet is paused */ + if (atomic_read(&ts->count)) + return; + if (TASKLET_ST_CMPSET(ts, TASKLET_ST_EXEC, TASKLET_ST_LOOP)) { /* tasklet_handler() will loop */ } else if (TASKLET_ST_CMPSET(ts, TASKLET_ST_IDLE, TASKLET_ST_BUSY)) { @@ -201,17 +215,39 @@ tasklet_kill(struct tasklet_struct *ts) void tasklet_enable(struct tasklet_struct *ts) { - (void) TASKLET_ST_CMPSET(ts, TASKLET_ST_PAUSED, TASKLET_ST_IDLE); + + atomic_dec(&ts->count); } void tasklet_disable(struct tasklet_struct *ts) { - while (1) { - if (TASKLET_ST_GET(ts) == TASKLET_ST_PAUSED) - break; - if (TASKLET_ST_CMPSET(ts, TASKLET_ST_IDLE, TASKLET_ST_PAUSED)) - break; + + atomic_inc(&ts->count); + tasklet_unlock_wait(ts); +} + +int +tasklet_trylock(struct tasklet_struct *ts) +{ + + return (TASKLET_ST_CMPSET(ts, TASKLET_ST_IDLE, TASKLET_ST_BUSY)); +} + +void +tasklet_unlock(struct tasklet_struct *ts) +{ + + TASKLET_ST_SET(ts, TASKLET_ST_IDLE); +} + +void +tasklet_unlock_wait(struct tasklet_struct *ts) +{ + + WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "tasklet_kill() can sleep"); + + /* wait until tasklet is no longer busy */ + while (TASKLET_ST_GET(ts) != TASKLET_ST_IDLE) pause("W", 1); - } }
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