| // Copyright 2016 The Fuchsia Authors |
| // Copyright (c) 2008-2014 Travis Geiselbrecht |
| // |
| // Use of this source code is governed by a MIT-style |
| // license that can be found in the LICENSE file or at |
| // https://opensource.org/licenses/MIT |
| |
| #pragma once |
| |
| #include <arch/defines.h> |
| #include <arch/ops.h> |
| #include <arch/thread.h> |
| #include <kernel/deadline.h> |
| #include <kernel/spinlock.h> |
| #include <kernel/timer.h> |
| #include <list.h> |
| #include <sys/types.h> |
| #include <zircon/compiler.h> |
| #include <zircon/types.h> |
| |
| __BEGIN_CDECLS |
| |
| extern spin_lock_t thread_lock; |
| |
| // wait queue stuff |
| #define WAIT_QUEUE_MAGIC (0x77616974) // 'wait' |
| |
| typedef struct wait_queue { |
| int magic; |
| int count; |
| struct list_node heads; |
| } wait_queue_t; |
| |
| #define WAIT_QUEUE_INITIAL_VALUE(q) \ |
| { \ |
| .magic = WAIT_QUEUE_MAGIC, \ |
| .count = 0, \ |
| .heads = LIST_INITIAL_VALUE((q).heads), \ |
| } |
| |
| // When blocking this enum indicates the kind of resource ownership that is being waited for |
| // that is causing the block. |
| enum class ResourceOwnership { |
| // Blocking is either not for any particular resource, or it is to wait for |
| // exclusive access to a resource. |
| Normal, |
| // Blocking is happening whilst waiting for shared read access to a resource. |
| Reader, |
| }; |
| |
| // wait queue primitive |
| // NOTE: must be inside critical section when using these |
| void wait_queue_init(wait_queue_t* wait); |
| |
| void wait_queue_destroy(wait_queue_t*); |
| |
| // block on a wait queue. |
| // return status is whatever the caller of wait_queue_wake_*() specifies. |
| // a deadline other than ZX_TIME_INFINITE will abort at the specified time |
| // and return ZX_ERR_TIMED_OUT. a deadline in the past will immediately return. |
| |
| zx_status_t wait_queue_block(wait_queue_t*, zx_time_t deadline) TA_REQ(thread_lock); |
| |
| // block on a wait queue, ignoring existing signals in |signal_mask|. |
| // return status is whatever the caller of wait_queue_wake_*() specifies or |
| // ZX_ERR_TIMED_OUT if the deadline has elapsed or is in the past. |
| // will never timeout when called with a deadline of ZX_TIME_INFINITE. |
| zx_status_t wait_queue_block_etc(wait_queue_t*, |
| const Deadline& deadline, |
| uint signal_mask, |
| ResourceOwnership reason) TA_REQ(thread_lock); |
| |
| // returns the highest priority of all the blocked threads on this wait queue. |
| // returns -1 if no threads are blocked. |
| |
| int wait_queue_blocked_priority(wait_queue_t*) TA_REQ(thread_lock); |
| |
| // returns the current highest priority blocked thread on this wait queue, or |
| // null if no threads are blocked. |
| struct thread* wait_queue_peek(wait_queue_t*) TA_REQ(thread_lock); |
| |
| // release one or more threads from the wait queue. |
| // reschedule = should the system reschedule if any is released. |
| // wait_queue_error = what wait_queue_block() should return for the blocking thread. |
| |
| int wait_queue_wake_one(wait_queue_t*, bool reschedule, |
| zx_status_t wait_queue_error) TA_REQ(thread_lock); |
| int wait_queue_wake_all(wait_queue_t*, bool reschedule, |
| zx_status_t wait_queue_error) TA_REQ(thread_lock); |
| struct thread* wait_queue_dequeue_one(wait_queue_t* wait, |
| zx_status_t wait_queue_error) TA_REQ(thread_lock); |
| |
| // is the wait queue currently empty |
| bool wait_queue_is_empty(wait_queue_t*) TA_REQ(thread_lock); |
| |
| // remove a specific thread out of a wait queue it's blocked on |
| zx_status_t wait_queue_unblock_thread(struct thread* t, |
| zx_status_t wait_queue_error) TA_REQ(thread_lock); |
| |
| // a thread's priority has changed, potentially modify the wait queue it's in |
| void wait_queue_priority_changed(struct thread* t, |
| int old_prio) TA_REQ(thread_lock); |
| |
| // validate that the queue of a given wait queue is valid |
| void wait_queue_validate_queue(wait_queue_t* wait) TA_REQ(thread_lock); |
| |
| __END_CDECLS |
| |
| #ifdef __cplusplus |
| |
| class WaitQueue { |
| public: |
| WaitQueue() {} |
| ~WaitQueue() { wait_queue_destroy(&wq_); } |
| |
| WaitQueue(WaitQueue&) = delete; |
| WaitQueue(WaitQueue&&) = delete; |
| WaitQueue& operator=(WaitQueue&) = delete; |
| WaitQueue& operator=(WaitQueue&&) = delete; |
| |
| zx_status_t Block(const Deadline& deadline) TA_REQ(thread_lock) { |
| return wait_queue_block_etc(&wq_, deadline, 0, ResourceOwnership::Normal); |
| } |
| |
| zx_status_t BlockReadLock(const Deadline& deadline) TA_REQ(thread_lock) { |
| return wait_queue_block_etc(&wq_, deadline, 0, ResourceOwnership::Reader); |
| } |
| |
| struct thread* Peek() TA_REQ(thread_lock) { |
| return wait_queue_peek(&wq_); |
| } |
| |
| int WakeOne(bool reschedule, zx_status_t wait_queue_error) TA_REQ(thread_lock) { |
| return wait_queue_wake_one(&wq_, reschedule, wait_queue_error); |
| } |
| |
| bool IsEmpty() TA_REQ(thread_lock) { return wait_queue_is_empty(&wq_); } |
| |
| static zx_status_t UnblockThread(struct thread* t, zx_status_t wait_queue_error) |
| TA_REQ(thread_lock) { |
| return wait_queue_unblock_thread(t, wait_queue_error); |
| } |
| |
| private: |
| wait_queue_t wq_ = WAIT_QUEUE_INITIAL_VALUE(wq_); |
| }; |
| |
| #endif // __cplusplus |