From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- drivers/char/drm/drm_lock.c | 303 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 303 insertions(+) create mode 100644 drivers/char/drm/drm_lock.c (limited to 'drivers/char/drm/drm_lock.c') diff --git a/drivers/char/drm/drm_lock.c b/drivers/char/drm/drm_lock.c new file mode 100644 index 000000000000..d0d6fc661625 --- /dev/null +++ b/drivers/char/drm/drm_lock.c @@ -0,0 +1,303 @@ +/** + * \file drm_lock.h + * IOCTLs for locking + * + * \author Rickard E. (Rik) Faith + * \author Gareth Hughes + */ + +/* + * 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. + */ + +#include "drmP.h" + +/** + * Lock ioctl. + * + * \param inode device inode. + * \param filp file pointer. + * \param cmd command. + * \param arg user argument, pointing to a drm_lock structure. + * \return zero on success or negative number on failure. + * + * Add the current task to the lock wait queue, and attempt to take to lock. + */ +int drm_lock( struct inode *inode, struct file *filp, + unsigned int cmd, unsigned long arg ) +{ + drm_file_t *priv = filp->private_data; + drm_device_t *dev = priv->head->dev; + DECLARE_WAITQUEUE( entry, current ); + drm_lock_t lock; + int ret = 0; + + ++priv->lock_count; + + if ( copy_from_user( &lock, (drm_lock_t __user *)arg, sizeof(lock) ) ) + return -EFAULT; + + if ( lock.context == DRM_KERNEL_CONTEXT ) { + DRM_ERROR( "Process %d using kernel context %d\n", + current->pid, lock.context ); + return -EINVAL; + } + + DRM_DEBUG( "%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n", + lock.context, current->pid, + dev->lock.hw_lock->lock, lock.flags ); + + if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE)) + if ( lock.context < 0 ) + return -EINVAL; + + add_wait_queue( &dev->lock.lock_queue, &entry ); + for (;;) { + __set_current_state(TASK_INTERRUPTIBLE); + if ( !dev->lock.hw_lock ) { + /* Device has been unregistered */ + ret = -EINTR; + break; + } + if ( drm_lock_take( &dev->lock.hw_lock->lock, + lock.context ) ) { + dev->lock.filp = filp; + dev->lock.lock_time = jiffies; + atomic_inc( &dev->counts[_DRM_STAT_LOCKS] ); + break; /* Got lock */ + } + + /* Contention */ + schedule(); + if ( signal_pending( current ) ) { + ret = -ERESTARTSYS; + break; + } + } + __set_current_state(TASK_RUNNING); + remove_wait_queue( &dev->lock.lock_queue, &entry ); + + sigemptyset( &dev->sigmask ); + sigaddset( &dev->sigmask, SIGSTOP ); + sigaddset( &dev->sigmask, SIGTSTP ); + sigaddset( &dev->sigmask, SIGTTIN ); + sigaddset( &dev->sigmask, SIGTTOU ); + dev->sigdata.context = lock.context; + dev->sigdata.lock = dev->lock.hw_lock; + block_all_signals( drm_notifier, + &dev->sigdata, &dev->sigmask ); + + if (dev->driver->dma_ready && (lock.flags & _DRM_LOCK_READY)) + dev->driver->dma_ready(dev); + + if ( dev->driver->dma_quiescent && (lock.flags & _DRM_LOCK_QUIESCENT )) + return dev->driver->dma_quiescent(dev); + + /* dev->driver->kernel_context_switch isn't used by any of the x86 + * drivers but is used by the Sparc driver. + */ + + if (dev->driver->kernel_context_switch && + dev->last_context != lock.context) { + dev->driver->kernel_context_switch(dev, dev->last_context, + lock.context); + } + DRM_DEBUG( "%d %s\n", lock.context, ret ? "interrupted" : "has lock" ); + + return ret; +} + +/** + * Unlock ioctl. + * + * \param inode device inode. + * \param filp file pointer. + * \param cmd command. + * \param arg user argument, pointing to a drm_lock structure. + * \return zero on success or negative number on failure. + * + * Transfer and free the lock. + */ +int drm_unlock( struct inode *inode, struct file *filp, + unsigned int cmd, unsigned long arg ) +{ + drm_file_t *priv = filp->private_data; + drm_device_t *dev = priv->head->dev; + drm_lock_t lock; + + if ( copy_from_user( &lock, (drm_lock_t __user *)arg, sizeof(lock) ) ) + return -EFAULT; + + if ( lock.context == DRM_KERNEL_CONTEXT ) { + DRM_ERROR( "Process %d using kernel context %d\n", + current->pid, lock.context ); + return -EINVAL; + } + + atomic_inc( &dev->counts[_DRM_STAT_UNLOCKS] ); + + /* kernel_context_switch isn't used by any of the x86 drm + * modules but is required by the Sparc driver. + */ + if (dev->driver->kernel_context_switch_unlock) + dev->driver->kernel_context_switch_unlock(dev, &lock); + else { + drm_lock_transfer( dev, &dev->lock.hw_lock->lock, + DRM_KERNEL_CONTEXT ); + + if ( drm_lock_free( dev, &dev->lock.hw_lock->lock, + DRM_KERNEL_CONTEXT ) ) { + DRM_ERROR( "\n" ); + } + } + + unblock_all_signals(); + return 0; +} + +/** + * Take the heavyweight lock. + * + * \param lock lock pointer. + * \param context locking context. + * \return one if the lock is held, or zero otherwise. + * + * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. + */ +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. + * + * \param dev DRM device. + * \param lock lock pointer. + * \param context locking context. + * \return always one. + * + * Resets the lock file pointer. + * Marks the lock as held by the given context, via the \p cmpxchg instruction. + */ +int drm_lock_transfer(drm_device_t *dev, + __volatile__ unsigned int *lock, unsigned int context) +{ + unsigned int old, new, prev; + + dev->lock.filp = NULL; + do { + old = *lock; + new = context | _DRM_LOCK_HELD; + prev = cmpxchg(lock, old, new); + } while (prev != old); + return 1; +} + +/** + * Free lock. + * + * \param dev DRM device. + * \param lock lock. + * \param context context. + * + * Resets the lock file pointer. + * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task + * waiting on the lock queue. + */ +int drm_lock_free(drm_device_t *dev, + __volatile__ unsigned int *lock, unsigned int context) +{ + unsigned int old, new, prev; + + dev->lock.filp = NULL; + 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\n", + context, + _DRM_LOCKING_CONTEXT(old)); + return 1; + } + wake_up_interruptible(&dev->lock.lock_queue); + return 0; +} + +/** + * 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. + * + * \param priv pointer to a drm_sigdata structure. + * \return one if the signal should be delivered normally, or zero 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 (!s->lock || !_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; +} -- cgit v1.2.3