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/* lock.c -- IOCTLs for locking -*- linux-c -*-
* Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
*
* Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
* Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
* 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
* VA LINUX SYSTEMS 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.
*
* Authors:
* Rickard E. (Rik) Faith <faith@valinux.com>
* Gareth Hughes <gareth@valinux.com>
*/
#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;
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 */
return 1;
}
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);
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;
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);
add_wait_queue(&q->flush_queue, &entry);
atomic_inc(&q->block_count);
for (;;) {
current->state = TASK_INTERRUPTIBLE;
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);
/* 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");
if (copy_from_user(&lock, (drm_lock_t *)arg, sizeof(lock)))
return -EFAULT;
ret = DRM(flush_block_and_flush)(dev, lock.context, lock.flags);
DRM(flush_unblock)(dev, lock.context, lock.flags);
return ret;
}
/* If we get here, it means that the process has called DRM_IOCTL_LOCK
without calling DRM_IOCTL_UNLOCK.
If the lock is not held, then let the signal proceed as usual.
If the lock is held, then set the contended flag and keep the signal
blocked.
Return 1 if the signal should be delivered normally.
Return 0 if the signal should be blocked. */
int DRM(notifier)(void *priv)
{
drm_sigdata_t *s = (drm_sigdata_t *)priv;
unsigned int old, new, prev;
/* Allow signal delivery if lock isn't held */
if (!_DRM_LOCK_IS_HELD(s->lock->lock)
|| _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context) return 1;
/* Otherwise, set flag to force call to
drmUnlock */
do {
old = s->lock->lock;
new = old | _DRM_LOCK_CONT;
prev = cmpxchg(&s->lock->lock, old, new);
} while (prev != old);
return 0;
}
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