/*
* drivers/base/sync.c
*
* Copyright (C) 2012 Google, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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.
*
*/
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/anon_inodes.h>
#include "sync.h"
static void sync_fence_signal_pt(struct sync_pt *pt);
static int _sync_pt_has_signaled(struct sync_pt *pt);
struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
int size, const char *name)
{
struct sync_timeline *obj;
if (size < sizeof(struct sync_timeline))
return NULL;
obj = kzalloc(size, GFP_KERNEL);
if (obj == NULL)
return NULL;
obj->ops = ops;
strlcpy(obj->name, name, sizeof(obj->name));
INIT_LIST_HEAD(&obj->child_list_head);
spin_lock_init(&obj->child_list_lock);
INIT_LIST_HEAD(&obj->active_list_head);
spin_lock_init(&obj->active_list_lock);
return obj;
}
void sync_timeline_destroy(struct sync_timeline *obj)
{
unsigned long flags;
bool needs_freeing;
spin_lock_irqsave(&obj->child_list_lock, flags);
obj->destroyed = true;
needs_freeing = list_empty(&obj->child_list_head);
spin_unlock_irqrestore(&obj->child_list_lock, flags);
if (needs_freeing)
kfree(obj);
else
sync_timeline_signal(obj);
}
static void sync_timeline_add_pt(struct sync_timeline *obj, struct sync_pt *pt)
{
unsigned long flags;
pt->parent = obj;
spin_lock_irqsave(&obj->child_list_lock, flags);
list_add_tail(&pt->child_list, &obj->child_list_head);
spin_unlock_irqrestore(&obj->child_list_lock, flags);
}
static void sync_timeline_remove_pt(struct sync_pt *pt)
{
struct sync_timeline *obj = pt->parent;
unsigned long flags;
bool needs_freeing;
spin_lock_irqsave(&obj->active_list_lock, flags);
if (!list_empty(&pt->active_list))
list_del_init(&pt->active_list);
spin_unlock_irqrestore(&obj->active_list_lock, flags);
spin_lock_irqsave(&obj->child_list_lock, flags);
list_del(&pt->child_list);
needs_freeing = obj->destroyed && list_empty(&obj->child_list_head);
spin_unlock_irqrestore(&obj->child_list_lock, flags);
if (needs_freeing)
kfree(obj);
}
void sync_timeline_signal(struct sync_timeline *obj)
{
unsigned long flags;
LIST_HEAD(signaled_pts);
struct list_head *pos, *n;
spin_lock_irqsave(&obj->active_list_lock, flags);
list_for_each_safe(pos, n, &obj->active_list_head) {
struct sync_pt *pt =
container_of(pos, struct sync_pt, active_list);
if (_sync_pt_has_signaled(pt))
list_move(pos, &signaled_pts);
}
spin_unlock_irqrestore(&obj->active_list_lock, flags);
list_for_each_safe(pos, n, &signaled_pts) {
struct sync_pt *pt =
container_of(pos, struct sync_pt, active_list);
list_del_init(pos);
sync_fence_signal_pt(pt);
}
}
struct sync_pt *sync_pt_create(struct sync_timeline *parent, int size)
{
struct sync_pt *pt;
if (size < sizeof(struct sync_pt))
return NULL;
pt = kzalloc(size, GFP_KERNEL);
if (pt == NULL)
return NULL;
INIT_LIST_HEAD(&pt->active_list);
sync_timeline_add_pt(parent, pt);
return pt;
}
void sync_pt_free(struct sync_pt *pt)
{
if (pt->parent->ops->free_pt)
pt->parent->ops->free_pt(pt);
sync_timeline_remove_pt(pt);
kfree(pt);
}
/* call with pt->parent->active_list_lock held */
static int _sync_pt_has_signaled(struct sync_pt *pt)
{
if (!pt->status)
pt->status = pt->parent->ops->has_signaled(pt);
if (!pt->status && pt->parent->destroyed)
pt->status = -ENOENT;
return pt->status;
}
static struct sync_pt *sync_pt_dup(struct sync_pt *pt)
{
return pt->parent->ops->dup(pt);
}
/* Adds a sync pt to the active queue. Called when added to a fence */
static void sync_pt_activate(struct sync_pt *pt)
{
struct sync_timeline *obj = pt->parent;
unsigned long flags;
int err;
spin_lock_irqsave(&obj->active_list_lock, flags);
err = _sync_pt_has_signaled(pt);
if (err != 0)
goto out;
list_add_tail(&pt->active_list, &obj->active_list_head);
out:
spin_unlock_irqrestore(&obj->active_list_lock, flags);
}
static int sync_fence_release(struct inode *inode, struct file *file);
static long sync_fence_ioctl(struct file *file, unsigned int cmd,
unsigned long arg);
static const struct file_operations sync_fence_fops = {
.release = sync_fence_release,
.unlocked_ioctl = sync_fence_ioctl,
};
static struct sync_fence *sync_fence_alloc(const char *name)
{
struct sync_fence *fence;
fence = kzalloc(sizeof(struct sync_fence), GFP_KERNEL);
if (fence == NULL)
return NULL;
fence->file = anon_inode_getfile("sync_fence", &sync_fence_fops,
fence, 0);
if (fence->file == NULL)
goto err;
strlcpy(fence->name, name, sizeof(fence->name));
INIT_LIST_HEAD(&fence->pt_list_head);
INIT_LIST_HEAD(&fence->waiter_list_head);
spin_lock_init(&fence->waiter_list_lock);
init_waitqueue_head(&fence->wq);
return fence;
err:
kfree(fence);
return NULL;
}
/* TODO: implement a create which takes more that one sync_pt */
struct sync_fence *sync_fence_create(const char *name, struct sync_pt *pt)
{
struct sync_fence *fence;
if (pt->fence)
return NULL;
fence = sync_fence_alloc(name);
if (fence == NULL)
return NULL;
pt->fence = fence;
list_add(&pt->pt_list, &fence->pt_list_head);
sync_pt_activate(pt);
return fence;
}
static int sync_fence_copy_pts(struct sync_fence *dst, struct sync_fence *src)
{
struct list_head *pos;
list_for_each(pos, &src->pt_list_head) {
struct sync_pt *orig_pt =
container_of(pos, struct sync_pt, pt_list);
struct sync_pt *new_pt = sync_pt_dup(orig_pt);
if (new_pt == NULL)
return -ENOMEM;
new_pt->fence = dst;
list_add(&new_pt->pt_list, &dst->pt_list_head);
sync_pt_activate(new_pt);
}
return 0;
}
static void sync_fence_free_pts(struct sync_fence *fence)
{
struct list_head *pos, *n;
list_for_each_safe(pos, n, &fence->pt_list_head) {
struct sync_pt *pt = container_of(pos, struct sync_pt, pt_list);
sync_pt_free(pt);
}
}
struct sync_fence *sync_fence_fdget(int fd)
{
struct file *file = fget(fd);
if (file == NULL)
return NULL;
if (file->f_op != &sync_fence_fops)
goto err;
return file->private_data;
err:
fput(file);
return NULL;
}
void sync_fence_put(struct sync_fence *fence)
{
fput(fence->file);
}
void sync_fence_install(struct sync_fence *fence, int fd)
{
fd_install(fd, fence->file);
}
static int sync_fence_get_status(struct sync_fence *fence)
{
struct list_head *pos;
int status = 1;
list_for_each(pos, &fence->pt_list_head) {
struct sync_pt *pt = container_of(pos, struct sync_pt, pt_list);
int pt_status = pt->status;
if (pt_status < 0) {
status = pt_status;
break;
} else if (status == 1) {
status = pt_status;
}
}
return status;
}
struct sync_fence *sync_fence_merge(const char *name,
struct sync_fence *a, struct sync_fence *b)
{
struct sync_fence *fence;
int err;
fence = sync_fence_alloc(name);
if (fence == NULL)
return NULL;
err = sync_fence_copy_pts(fence, a);
if (err < 0)
goto err;
err = sync_fence_copy_pts(fence, b);
if (err < 0)
goto err;
fence->status = sync_fence_get_status(fence);
return fence;
err:
sync_fence_free_pts(fence);
kfree(fence);
return NULL;
}
static void sync_fence_signal_pt(struct sync_pt *pt)
{
LIST_HEAD(signaled_waiters);
struct sync_fence *fence = pt->fence;
struct list_head *pos;
struct list_head *n;
unsigned long flags;
int status;
status = sync_fence_get_status(fence);
spin_lock_irqsave(&fence->waiter_list_lock, flags);
/*
* this should protect against two threads racing on the signaled
* false -> true transition
*/
if (status && !fence->status) {
list_for_each_safe(pos, n, &fence->waiter_list_head)
list_move(pos, &signaled_waiters);
fence->status = status;
} else {
status = 0;
}
spin_unlock_irqrestore(&fence->waiter_list_lock, flags);
if (status) {
list_for_each_safe(pos, n, &signaled_waiters) {
struct sync_fence_waiter *waiter =
container_of(pos, struct sync_fence_waiter,
waiter_list);
waiter->callback(fence, waiter->callback_data);
list_del(pos);
kfree(waiter);
}
wake_up(&fence->wq);
}
}
int sync_fence_wait_async(struct sync_fence *fence,
void (*callback)(struct sync_fence *, void *data),
void *callback_data)
{
struct sync_fence_waiter *waiter;
unsigned long flags;
int err = 0;
waiter = kzalloc(sizeof(struct sync_fence_waiter), GFP_KERNEL);
if (waiter == NULL)
return -ENOMEM;
waiter->callback = callback;
waiter->callback_data = callback_data;
spin_lock_irqsave(&fence->waiter_list_lock, flags);
if (fence->status) {
kfree(waiter);
err = fence->status;
goto out;
}
list_add_tail(&waiter->waiter_list, &fence->waiter_list_head);
out:
spin_unlock_irqrestore(&fence->waiter_list_lock, flags);
return err;
}
int sync_fence_wait(struct sync_fence *fence, long timeout)
{
int err;
if (timeout) {
timeout = msecs_to_jiffies(timeout);
err = wait_event_interruptible_timeout(fence->wq,
fence->status != 0,
timeout);
} else {
err = wait_event_interruptible(fence->wq, fence->status != 0);
}
if (err < 0)
return err;
if (fence->status < 0)
return fence->status;
if (fence->status == 0)
return -ETIME;
return 0;
}
static int sync_fence_release(struct inode *inode, struct file *file)
{
struct sync_fence *fence = file->private_data;
sync_fence_free_pts(fence);
kfree(fence);
return 0;
}
static long sync_fence_ioctl_wait(struct sync_fence *fence, unsigned long arg)
{
__s32 value;
if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
return -EFAULT;
return sync_fence_wait(fence, value);
}
static long sync_fence_ioctl_merge(struct sync_fence *fence, unsigned long arg)
{
int fd = get_unused_fd();
int err;
struct sync_fence *fence2, *fence3;
struct sync_merge_data data;
if (copy_from_user(&data, (void __user *)arg, sizeof(data)))
return -EFAULT;
fence2 = sync_fence_fdget(data.fd2);
if (fence2 == NULL) {
err = -ENOENT;
goto err_put_fd;
}
data.name[sizeof(data.name) - 1] = '\0';
fence3 = sync_fence_merge(data.name, fence, fence2);
if (fence3 == NULL) {
err = -ENOMEM;
goto err_put_fence2;
}
data.fence = fd;
if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
err = -EFAULT;
goto err_put_fence3;
}
sync_fence_install(fence3, fd);
sync_fence_put(fence2);
return 0;
err_put_fence3:
sync_fence_put(fence3);
err_put_fence2:
sync_fence_put(fence2);
err_put_fd:
put_unused_fd(fd);
return err;
}
static long sync_fence_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct sync_fence *fence = file->private_data;
switch (cmd) {
case SYNC_IOC_WAIT:
return sync_fence_ioctl_wait(fence, arg);
case SYNC_IOC_MERGE:
return sync_fence_ioctl_merge(fence, arg);
default:
return -ENOTTY;
}
}