/* lock.c -- IOCTLs for locking -*- linux-c -*- * Created: Tue Feb 2 08:37:54 1999 by faith@precisioninsight.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 * 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. * * Authors: * Rickard E. (Rik) Faith * */ #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); 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"); 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; }
