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/* lock.c -- IOCTLs for locking -*- linux-c -*-
* Created: Tue Feb 2 08:37:54 1999 by faith@precisioninsight.com
* Revised: Sun Feb 13 23:38:25 2000 by kevin@precisioninsight.com
*
* Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* $PI: xc/programs/Xserver/hw/xfree86/os-support/linux/drm/kernel/lock.c,v 1.5 1999/08/30 13:05:00 faith Exp $
* $XFree86: xc/programs/Xserver/hw/xfree86/os-support/linux/drm/kernel/lock.c,v 1.4 2000/02/14 06:27:27 martin Exp $
*
*/
#define __NO_VERSION__
#include "drmP.h"
int drm_block(struct inode *inode, struct file *filp, unsigned int cmd,
unsigned long arg)
{
DRM_DEBUG("\n");
return 0;
}
int drm_unblock(struct inode *inode, struct file *filp, unsigned int cmd,
unsigned long arg)
{
DRM_DEBUG("\n");
return 0;
}
int drm_lock_take(__volatile__ unsigned int *lock, unsigned int context)
{
unsigned int old, new, prev;
DRM_DEBUG("%d attempts\n", context);
do {
old = *lock;
if (old & _DRM_LOCK_HELD) new = old | _DRM_LOCK_CONT;
else new = context | _DRM_LOCK_HELD;
prev = cmpxchg(lock, old, new);
} while (prev != old);
if (_DRM_LOCKING_CONTEXT(old) == context) {
if (old & _DRM_LOCK_HELD) {
if (context != DRM_KERNEL_CONTEXT) {
DRM_ERROR("%d holds heavyweight lock\n",
context);
}
return 0;
}
}
if (new == (context | _DRM_LOCK_HELD)) {
/* Have lock */
DRM_DEBUG("%d\n", context);
return 1;
}
DRM_DEBUG("%d unable to get lock held by %d\n",
context, _DRM_LOCKING_CONTEXT(old));
return 0;
}
/* This takes a lock forcibly and hands it to context. Should ONLY be used
inside *_unlock to give lock to kernel before calling *_dma_schedule. */
int drm_lock_transfer(drm_device_t *dev,
__volatile__ unsigned int *lock, unsigned int context)
{
unsigned int old, new, prev;
dev->lock.pid = 0;
do {
old = *lock;
new = context | _DRM_LOCK_HELD;
prev = cmpxchg(lock, old, new);
} while (prev != old);
DRM_DEBUG("%d => %d\n", _DRM_LOCKING_CONTEXT(old), context);
return 1;
}
int drm_lock_free(drm_device_t *dev,
__volatile__ unsigned int *lock, unsigned int context)
{
unsigned int old, new, prev;
pid_t pid = dev->lock.pid;
DRM_DEBUG("%d\n", context);
dev->lock.pid = 0;
do {
old = *lock;
new = 0;
prev = cmpxchg(lock, old, new);
} while (prev != old);
if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
DRM_ERROR("%d freed heavyweight lock held by %d (pid %d)\n",
context,
_DRM_LOCKING_CONTEXT(old),
pid);
return 1;
}
wake_up_interruptible(&dev->lock.lock_queue);
return 0;
}
static int drm_flush_queue(drm_device_t *dev, int context)
{
DECLARE_WAITQUEUE(entry, current);
int ret = 0;
drm_queue_t *q = dev->queuelist[context];
DRM_DEBUG("\n");
atomic_inc(&q->use_count);
if (atomic_read(&q->use_count) > 1) {
atomic_inc(&q->block_write);
current->state = TASK_INTERRUPTIBLE;
add_wait_queue(&q->flush_queue, &entry);
atomic_inc(&q->block_count);
for (;;) {
if (!DRM_BUFCOUNT(&q->waitlist)) break;
schedule();
if (signal_pending(current)) {
ret = -EINTR; /* Can't restart */
break;
}
}
atomic_dec(&q->block_count);
current->state = TASK_RUNNING;
remove_wait_queue(&q->flush_queue, &entry);
}
atomic_dec(&q->use_count);
atomic_inc(&q->total_flushed);
/* NOTE: block_write is still incremented!
Use drm_flush_unlock_queue to decrement. */
return ret;
}
static int drm_flush_unblock_queue(drm_device_t *dev, int context)
{
drm_queue_t *q = dev->queuelist[context];
DRM_DEBUG("\n");
atomic_inc(&q->use_count);
if (atomic_read(&q->use_count) > 1) {
if (atomic_read(&q->block_write)) {
atomic_dec(&q->block_write);
wake_up_interruptible(&q->write_queue);
}
}
atomic_dec(&q->use_count);
return 0;
}
int drm_flush_block_and_flush(drm_device_t *dev, int context,
drm_lock_flags_t flags)
{
int ret = 0;
int i;
DRM_DEBUG("\n");
if (flags & _DRM_LOCK_FLUSH) {
ret = drm_flush_queue(dev, DRM_KERNEL_CONTEXT);
if (!ret) ret = drm_flush_queue(dev, context);
}
if (flags & _DRM_LOCK_FLUSH_ALL) {
for (i = 0; !ret && i < dev->queue_count; i++) {
ret = drm_flush_queue(dev, i);
}
}
return ret;
}
int drm_flush_unblock(drm_device_t *dev, int context, drm_lock_flags_t flags)
{
int ret = 0;
int i;
DRM_DEBUG("\n");
if (flags & _DRM_LOCK_FLUSH) {
ret = drm_flush_unblock_queue(dev, DRM_KERNEL_CONTEXT);
if (!ret) ret = drm_flush_unblock_queue(dev, context);
}
if (flags & _DRM_LOCK_FLUSH_ALL) {
for (i = 0; !ret && i < dev->queue_count; i++) {
ret = drm_flush_unblock_queue(dev, i);
}
}
return ret;
}
int drm_finish(struct inode *inode, struct file *filp, unsigned int cmd,
unsigned long arg)
{
drm_file_t *priv = filp->private_data;
drm_device_t *dev = priv->dev;
int ret = 0;
drm_lock_t lock;
DRM_DEBUG("\n");
copy_from_user_ret(&lock, (drm_lock_t *)arg, sizeof(lock), -EFAULT);
ret = drm_flush_block_and_flush(dev, lock.context, lock.flags);
drm_flush_unblock(dev, lock.context, lock.flags);
return ret;
}
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