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- sync.h
/*
* include/linux/sync.h
*
* Copyright (C) 2012 Google, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#ifndef _LINUX_SYNC_H
#define _LINUX_SYNC_H
#include <linux/types.h>
#include <linux/kref.h>
#include <linux/ktime.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include "uapi/sync.h"
struct sync_timeline;
struct sync_pt;
struct sync_fence;
/**
* struct sync_timeline_ops - sync object implementation ops
* @driver_name: name of the implementation
* @dup: duplicate a sync_pt
* @has_signaled: returns:
* 1 if pt has signaled
* 0 if pt has not signaled
* <0 on error
* @compare: returns:
* 1 if b will signal before a
* 0 if a and b will signal at the same time
* -1 if a will signal before b
* @free_pt: called before sync_pt is freed
* @release_obj: called before sync_timeline is freed
* @print_obj: deprecated
* @print_pt: deprecated
* @fill_driver_data: write implementation specific driver data to data.
* should return an error if there is not enough room
* as specified by size. This information is returned
* to userspace by SYNC_IOC_FENCE_INFO.
* @timeline_value_str: fill str with the value of the sync_timeline's counter
* @pt_value_str: fill str with the value of the sync_pt
*/
struct sync_timeline_ops {
const char *driver_name;
/* required */
struct sync_pt *(*dup)(struct sync_pt *pt);
/* required */
int (*has_signaled)(struct sync_pt *pt);
/* required */
int (*compare)(struct sync_pt *a, struct sync_pt *b);
/* optional */
void (*free_pt)(struct sync_pt *sync_pt);
/* optional */
void (*release_obj)(struct sync_timeline *sync_timeline);
/* deprecated */
void (*print_obj)(struct seq_file *s,
struct sync_timeline *sync_timeline);
/* deprecated */
void (*print_pt)(struct seq_file *s, struct sync_pt *sync_pt);
/* optional */
int (*fill_driver_data)(struct sync_pt *syncpt, void *data, int size);
/* optional */
void (*timeline_value_str)(struct sync_timeline *timeline, char *str,
int size);
/* optional */
void (*pt_value_str)(struct sync_pt *pt, char *str, int size);
};
/**
* struct sync_timeline - sync object
* @kref: reference count on fence.
* @ops: ops that define the implementation of the sync_timeline
* @name: name of the sync_timeline. Useful for debugging
* @destroyed: set when sync_timeline is destroyed
* @child_list_head: list of children sync_pts for this sync_timeline
* @child_list_lock: lock protecting @child_list_head, destroyed, and
* sync_pt.status
* @active_list_head: list of active (unsignaled/errored) sync_pts
* @sync_timeline_list: membership in global sync_timeline_list
*/
struct sync_timeline {
struct kref kref;
const struct sync_timeline_ops *ops;
char name[32];
/* protected by child_list_lock */
bool destroyed;
struct list_head child_list_head;
spinlock_t child_list_lock;
struct list_head active_list_head;
spinlock_t active_list_lock;
struct list_head sync_timeline_list;
};
/**
* struct sync_pt - sync point
* : sync_timeline to which this sync_pt belongs
* @child_list: membership in sync_timeline.child_list_head
* @active_list: membership in sync_timeline.active_list_head
* @signaled_list: membership in temporary signaled_list on stack
* @fence: sync_fence to which the sync_pt belongs
* @pt_list: membership in sync_fence.pt_list_head
* @status: 1: signaled, 0:active, <0: error
* @timestamp: time which sync_pt status transitioned from active to
* signaled or error.
*/
struct sync_pt {
struct sync_timeline *parent;
struct list_head child_list;
struct list_head active_list;
struct list_head signaled_list;
struct sync_fence *fence;
struct list_head pt_list;
/* protected by parent->active_list_lock */
int status;
ktime_t timestamp;
};
/**
* struct sync_fence - sync fence
* @file: file representing this fence
* @kref: reference count on fence.
* @name: name of sync_fence. Useful for debugging
* @pt_list_head: list of sync_pts in the fence. immutable once fence
* is created
* @waiter_list_head: list of asynchronous waiters on this fence
* @waiter_list_lock: lock protecting @waiter_list_head and @status
* @status: 1: signaled, 0:active, <0: error
*
* @wq: wait queue for fence signaling
* @sync_fence_list: membership in global fence list
*/
struct sync_fence {
struct file *file;
struct kref kref;
char name[32];
/* this list is immutable once the fence is created */
struct list_head pt_list_head;
struct list_head waiter_list_head;
spinlock_t waiter_list_lock; /* also protects status */
int status;
wait_queue_head_t wq;
struct list_head sync_fence_list;
};
struct sync_fence_waiter;
typedef void (*sync_callback_t)(struct sync_fence *fence,
struct sync_fence_waiter *waiter);
/**
* struct sync_fence_waiter - metadata for asynchronous waiter on a fence
* @waiter_list: membership in sync_fence.waiter_list_head
* @callback: function pointer to call when fence signals
* @callback_data: pointer to pass to @callback
*/
struct sync_fence_waiter {
struct list_head waiter_list;
sync_callback_t callback;
};
static inline void sync_fence_waiter_init(struct sync_fence_waiter *waiter,
sync_callback_t callback)
{
waiter->callback = callback;
}
/*
* API for sync_timeline implementers
*/
/**
* sync_timeline_create() - creates a sync object
* @ops: specifies the implementation ops for the object
* @size: size to allocate for this obj
* @name: sync_timeline name
*
* Creates a new sync_timeline which will use the implementation specified by
* @ops. @size bytes will be allocated allowing for implementation specific
* data to be kept after the generic sync_timeline struct.
*/
struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
int size, const char *name);
/**
* sync_timeline_destroy() - destroys a sync object
* @obj: sync_timeline to destroy
*
* A sync implementation should call this when the @obj is going away
* (i.e. module unload.) @obj won't actually be freed until all its children
* sync_pts are freed.
*/
void sync_timeline_destroy(struct sync_timeline *obj);
/**
* sync_timeline_signal() - signal a status change on a sync_timeline
* @obj: sync_timeline to signal
*
* A sync implementation should call this any time one of it's sync_pts
* has signaled or has an error condition.
*/
void sync_timeline_signal(struct sync_timeline *obj);
/**
* sync_pt_create() - creates a sync pt
* : sync_pt's parent sync_timeline
* @size: size to allocate for this pt
*
* Creates a new sync_pt as a child of . @size bytes will be
* allocated allowing for implementation specific data to be kept after
* the generic sync_timeline struct.
*/
struct sync_pt *sync_pt_create(struct sync_timeline *parent, int size);
/**
* sync_pt_free() - frees a sync pt
* @pt: sync_pt to free
*
* This should only be called on sync_pts which have been created but
* not added to a fence.
*/
void sync_pt_free(struct sync_pt *pt);
/**
* sync_fence_create() - creates a sync fence
* @name: name of fence to create
* @pt: sync_pt to add to the fence
*
* Creates a fence containg @pt. Once this is called, the fence takes
* ownership of @pt.
*/
struct sync_fence *sync_fence_create(const char *name, struct sync_pt *pt);
/*
* API for sync_fence consumers
*/
/**
* sync_fence_merge() - merge two fences
* @name: name of new fence
* @a: fence a
* @b: fence b
*
* Creates a new fence which contains copies of all the sync_pts in both
* @a and @b. @a and @b remain valid, independent fences.
*/
struct sync_fence *sync_fence_merge(const char *name,
struct sync_fence *a, struct sync_fence *b);
/**
* sync_fence_fdget() - get a fence from an fd
* @fd: fd referencing a fence
*
* Ensures @fd references a valid fence, increments the refcount of the backing
* file, and returns the fence.
*/
struct sync_fence *sync_fence_fdget(int fd);
/**
* sync_fence_put() - puts a reference of a sync fence
* @fence: fence to put
*
* Puts a reference on @fence. If this is the last reference, the fence and
* all it's sync_pts will be freed
*/
void sync_fence_put(struct sync_fence *fence);
/**
* sync_fence_install() - installs a fence into a file descriptor
* @fence: fence to install
* @fd: file descriptor in which to install the fence
*
* Installs @fence into @fd. @fd's should be acquired through get_unused_fd().
*/
void sync_fence_install(struct sync_fence *fence, int fd);
/**
* sync_fence_wait_async() - registers and async wait on the fence
* @fence: fence to wait on
* @waiter: waiter callback struck
*
* Returns 1 if @fence has already signaled.
*
* Registers a callback to be called when @fence signals or has an error.
* @waiter should be initialized with sync_fence_waiter_init().
*/
int sync_fence_wait_async(struct sync_fence *fence,
struct sync_fence_waiter *waiter);
/**
* sync_fence_cancel_async() - cancels an async wait
* @fence: fence to wait on
* @waiter: waiter callback struck
*
* returns 0 if waiter was removed from fence's async waiter list.
* returns -ENOENT if waiter was not found on fence's async waiter list.
*
* Cancels a previously registered async wait. Will fail gracefully if
* @waiter was never registered or if @fence has already signaled @waiter.
*/
int sync_fence_cancel_async(struct sync_fence *fence,
struct sync_fence_waiter *waiter);
/**
* sync_fence_wait() - wait on fence
* @fence: fence to wait on
* @tiemout: timeout in ms
*
* Wait for @fence to be signaled or have an error. Waits indefinitely
* if @timeout < 0
*/
int sync_fence_wait(struct sync_fence *fence, long timeout);
#endif /* _LINUX_SYNC_H */