drivers/char/drm/gamma_lock.h

   1 /* lock.c -- IOCTLs for locking -*- linux-c -*-
   2  * Created: Tue Feb  2 08:37:54 1999 by faith@valinux.com
   3  *
   4  * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
   5  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
   6  * All Rights Reserved.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the "Software"),
  10  * to deal in the Software without restriction, including without limitation
  11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12  * and/or sell copies of the Software, and to permit persons to whom the
  13  * Software is furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the next
  16  * paragraph) shall be included in all copies or substantial portions of the
  17  * Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  22  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  23  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  24  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  25  * OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  * Authors:
  28  *    Rickard E. (Rik) Faith <faith@valinux.com>
  29  *    Gareth Hughes <gareth@valinux.com>
  30  */
  31
  32
  33 /* Gamma-specific code extracted from drm_lock.h:
  34  */
  35 static int DRM(flush_queue)(drm_device_t *dev, int context)
  36 {
  37         DECLARE_WAITQUEUE(entry, current);
  38         int               ret   = 0;
  39         drm_queue_t       *q    = dev->queuelist[context];
  40
  41         DRM_DEBUG("\n");
  42
  43         atomic_inc(&q->use_count);
  44         if (atomic_read(&q->use_count) > 1) {
  45                 atomic_inc(&q->block_write);
  46                 add_wait_queue(&q->flush_queue, &entry);
  47                 atomic_inc(&q->block_count);
  48                 for (;;) {
  49                         current->state = TASK_INTERRUPTIBLE;
  50                         if (!DRM_BUFCOUNT(&q->waitlist)) break;
  51                         schedule();
  52                         if (signal_pending(current)) {
  53                                 ret = -EINTR; /* Can't restart */
  54                                 break;
  55                         }
  56                 }
  57                 atomic_dec(&q->block_count);
  58                 current->state = TASK_RUNNING;
  59                 remove_wait_queue(&q->flush_queue, &entry);
  60         }
  61         atomic_dec(&q->use_count);
  62
  63                                 /* NOTE: block_write is still incremented!
  64                                    Use drm_flush_unlock_queue to decrement. */
  65         return ret;
  66 }
  67
  68 static int DRM(flush_unblock_queue)(drm_device_t *dev, int context)
  69 {
  70         drm_queue_t       *q    = dev->queuelist[context];
  71
  72         DRM_DEBUG("\n");
  73
  74         atomic_inc(&q->use_count);
  75         if (atomic_read(&q->use_count) > 1) {
  76                 if (atomic_read(&q->block_write)) {
  77                         atomic_dec(&q->block_write);
  78                         wake_up_interruptible(&q->write_queue);
  79                 }
  80         }
  81         atomic_dec(&q->use_count);
  82         return 0;
  83 }
  84
  85 int DRM(flush_block_and_flush)(drm_device_t *dev, int context,
  86                                drm_lock_flags_t flags)
  87 {
  88         int ret = 0;
  89         int i;
  90
  91         DRM_DEBUG("\n");
  92
  93         if (flags & _DRM_LOCK_FLUSH) {
  94                 ret = DRM(flush_queue)(dev, DRM_KERNEL_CONTEXT);
  95                 if (!ret) ret = DRM(flush_queue)(dev, context);
  96         }
  97         if (flags & _DRM_LOCK_FLUSH_ALL) {
  98                 for (i = 0; !ret && i < dev->queue_count; i++) {
  99                         ret = DRM(flush_queue)(dev, i);
 100                 }
 101         }
 102         return ret;
 103 }
 104
 105 int DRM(flush_unblock)(drm_device_t *dev, int context, drm_lock_flags_t flags)
 106 {
 107         int ret = 0;
 108         int i;
 109
 110         DRM_DEBUG("\n");
 111
 112         if (flags & _DRM_LOCK_FLUSH) {
 113                 ret = DRM(flush_unblock_queue)(dev, DRM_KERNEL_CONTEXT);
 114                 if (!ret) ret = DRM(flush_unblock_queue)(dev, context);
 115         }
 116         if (flags & _DRM_LOCK_FLUSH_ALL) {
 117                 for (i = 0; !ret && i < dev->queue_count; i++) {
 118                         ret = DRM(flush_unblock_queue)(dev, i);
 119                 }
 120         }
 121
 122         return ret;
 123 }
 124
 125 int DRM(finish)(struct inode *inode, struct file *filp, unsigned int cmd,
 126                 unsigned long arg)
 127 {
 128         drm_file_t        *priv   = filp->private_data;
 129         drm_device_t      *dev    = priv->dev;
 130         int               ret     = 0;
 131         drm_lock_t        lock;
 132
 133         DRM_DEBUG("\n");
 134
 135         if (copy_from_user(&lock, (drm_lock_t __user *)arg, sizeof(lock)))
 136                 return -EFAULT;
 137         ret = DRM(flush_block_and_flush)(dev, lock.context, lock.flags);
 138         DRM(flush_unblock)(dev, lock.context, lock.flags);
 139         return ret;
 140 }