drm_context.c

来自「LINUX 2.6.17.4的源码」· C语言 代码 · 共 595 行 · 第 1/2 页

}

/*@}*/

/******************************************************************/
/** \name The actual DRM context handling routines */
/*@{*/

/**
 * Switch context.
 *
 * \param dev DRM device.
 * \param old old context handle.
 * \param new new context handle.
 * \return zero on success or a negative number on failure.
 *
 * Attempt to set drm_device::context_flag.
 */
static int drm_context_switch(drm_device_t * dev, int old, int new)
{
	if (test_and_set_bit(0, &dev->context_flag)) {
		DRM_ERROR("Reentering -- FIXME\n");
		return -EBUSY;
	}

	DRM_DEBUG("Context switch from %d to %d\n", old, new);

	if (new == dev->last_context) {
		clear_bit(0, &dev->context_flag);
		return 0;
	}

	return 0;
}

/**
 * Complete context switch.
 *
 * \param dev DRM device.
 * \param new new context handle.
 * \return zero on success or a negative number on failure.
 *
 * Updates drm_device::last_context and drm_device::last_switch. Verifies the
 * hardware lock is held, clears the drm_device::context_flag and wakes up
 * drm_device::context_wait.
 */
static int drm_context_switch_complete(drm_device_t * dev, int new)
{
	dev->last_context = new;	/* PRE/POST: This is the _only_ writer. */
	dev->last_switch = jiffies;

	if (!_DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock)) {
		DRM_ERROR("Lock isn't held after context switch\n");
	}

	/* If a context switch is ever initiated
	   when the kernel holds the lock, release
	   that lock here. */
	clear_bit(0, &dev->context_flag);
	wake_up(&dev->context_wait);

	return 0;
}

/**
 * Reserve contexts.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx_res structure.
 * \return zero on success or a negative number on failure.
 */
int drm_resctx(struct inode *inode, struct file *filp,
	       unsigned int cmd, unsigned long arg)
{
	drm_ctx_res_t res;
	drm_ctx_t __user *argp = (void __user *)arg;
	drm_ctx_t ctx;
	int i;

	if (copy_from_user(&res, argp, sizeof(res)))
		return -EFAULT;

	if (res.count >= DRM_RESERVED_CONTEXTS) {
		memset(&ctx, 0, sizeof(ctx));
		for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
			ctx.handle = i;
			if (copy_to_user(&res.contexts[i], &ctx, sizeof(ctx)))
				return -EFAULT;
		}
	}
	res.count = DRM_RESERVED_CONTEXTS;

	if (copy_to_user(argp, &res, sizeof(res)))
		return -EFAULT;
	return 0;
}

/**
 * Add context.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 *
 * Get a new handle for the context and copy to userspace.
 */
int drm_addctx(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_ctx_list_t *ctx_entry;
	drm_ctx_t __user *argp = (void __user *)arg;
	drm_ctx_t ctx;

	if (copy_from_user(&ctx, argp, sizeof(ctx)))
		return -EFAULT;

	ctx.handle = drm_ctxbitmap_next(dev);
	if (ctx.handle == DRM_KERNEL_CONTEXT) {
		/* Skip kernel's context and get a new one. */
		ctx.handle = drm_ctxbitmap_next(dev);
	}
	DRM_DEBUG("%d\n", ctx.handle);
	if (ctx.handle == -1) {
		DRM_DEBUG("Not enough free contexts.\n");
		/* Should this return -EBUSY instead? */
		return -ENOMEM;
	}

	if (ctx.handle != DRM_KERNEL_CONTEXT) {
		if (dev->driver->context_ctor)
			if (!dev->driver->context_ctor(dev, ctx.handle)) {
				DRM_DEBUG("Running out of ctxs or memory.\n");
				return -ENOMEM;
			}
	}

	ctx_entry = drm_alloc(sizeof(*ctx_entry), DRM_MEM_CTXLIST);
	if (!ctx_entry) {
		DRM_DEBUG("out of memory\n");
		return -ENOMEM;
	}

	INIT_LIST_HEAD(&ctx_entry->head);
	ctx_entry->handle = ctx.handle;
	ctx_entry->tag = priv;

	mutex_lock(&dev->ctxlist_mutex);
	list_add(&ctx_entry->head, &dev->ctxlist->head);
	++dev->ctx_count;
	mutex_unlock(&dev->ctxlist_mutex);

	if (copy_to_user(argp, &ctx, sizeof(ctx)))
		return -EFAULT;
	return 0;
}

int drm_modctx(struct inode *inode, struct file *filp,
	       unsigned int cmd, unsigned long arg)
{
	/* This does nothing */
	return 0;
}

/**
 * Get context.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 */
int drm_getctx(struct inode *inode, struct file *filp,
	       unsigned int cmd, unsigned long arg)
{
	drm_ctx_t __user *argp = (void __user *)arg;
	drm_ctx_t ctx;

	if (copy_from_user(&ctx, argp, sizeof(ctx)))
		return -EFAULT;

	/* This is 0, because we don't handle any context flags */
	ctx.flags = 0;

	if (copy_to_user(argp, &ctx, sizeof(ctx)))
		return -EFAULT;
	return 0;
}

/**
 * Switch context.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 *
 * Calls context_switch().
 */
int drm_switchctx(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_ctx_t ctx;

	if (copy_from_user(&ctx, (drm_ctx_t __user *) arg, sizeof(ctx)))
		return -EFAULT;

	DRM_DEBUG("%d\n", ctx.handle);
	return drm_context_switch(dev, dev->last_context, ctx.handle);
}

/**
 * New context.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 *
 * Calls context_switch_complete().
 */
int drm_newctx(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_ctx_t ctx;

	if (copy_from_user(&ctx, (drm_ctx_t __user *) arg, sizeof(ctx)))
		return -EFAULT;

	DRM_DEBUG("%d\n", ctx.handle);
	drm_context_switch_complete(dev, ctx.handle);

	return 0;
}

/**
 * Remove context.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 *
 * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
 */
int drm_rmctx(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_ctx_t ctx;

	if (copy_from_user(&ctx, (drm_ctx_t __user *) arg, sizeof(ctx)))
		return -EFAULT;

	DRM_DEBUG("%d\n", ctx.handle);
	if (ctx.handle == DRM_KERNEL_CONTEXT + 1) {
		priv->remove_auth_on_close = 1;
	}
	if (ctx.handle != DRM_KERNEL_CONTEXT) {
		if (dev->driver->context_dtor)
			dev->driver->context_dtor(dev, ctx.handle);
		drm_ctxbitmap_free(dev, ctx.handle);
	}

	mutex_lock(&dev->ctxlist_mutex);
	if (!list_empty(&dev->ctxlist->head)) {
		drm_ctx_list_t *pos, *n;

		list_for_each_entry_safe(pos, n, &dev->ctxlist->head, head) {
			if (pos->handle == ctx.handle) {
				list_del(&pos->head);
				drm_free(pos, sizeof(*pos), DRM_MEM_CTXLIST);
				--dev->ctx_count;
			}
		}
	}
	mutex_unlock(&dev->ctxlist_mutex);

	return 0;
}

/*@}*/