OpenHarmony-v4.0-Release/s

/*
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Daryll Strauss <daryll@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Mon Jan  4 08:58:31 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 <linux/anon_inodes.h>
#include <linux/dma-fence.h>
#include <linux/file.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/poll.h>
#include <linux/slab.h>

#include <drm/drm_client.h>
#include <drm/drm_drv.h>
#include <drm/drm_file.h>
#include <drm/drm_print.h>

#include "drm_crtc_internal.h"
#include "drm_internal.h"
#include "drm_legacy.h"

#if defined(CONFIG_MMU) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
#include <uapi/asm/mman.h>
#include <drm/drm_vma_manager.h>
#endif

/* from BKL pushdown */
DEFINE_MUTEX(drm_global_mutex);

bool drm_dev_needs_global_mutex(struct drm_device *dev)
{
    /*
     * Legacy drivers rely on all kinds of BKL locking semantics, don't
     * bother. They also still need BKL locking for their ioctls, so better
     * safe than sorry.
     */
    if (drm_core_check_feature(dev, DRIVER_LEGACY)) {
        return true;
    }

    /*
     * The deprecated ->load callback must be called after the driver is
     * already registered. This means such drivers rely on the BKL to make
     * sure an open can't proceed until the driver is actually fully set up.
     * Similar hilarity holds for the unload callback.
     */
    if (dev->driver->load || dev->driver->unload) {
        return true;
    }

    /*
     * Drivers with the lastclose callback assume that it's synchronized
     * against concurrent opens, which again needs the BKL. The proper fix
     * is to use the drm_client infrastructure with proper locking for each
     * client.
     */
    if (dev->driver->lastclose) {
        return true;
    }

    return false;
}

/**
 * DOC: file operations
 *
 * Drivers must define the file operations structure that forms the DRM
 * userspace API entry point, even though most of those operations are
 * implemented in the DRM core. The resulting &struct file_operations must be
 * stored in the &drm_driver.fops field. The mandatory functions are drm_open(),
 * drm_read(), drm_ioctl() and drm_compat_ioctl() if CONFIG_COMPAT is enabled
 * Note that drm_compat_ioctl will be NULL if CONFIG_COMPAT=n, so there's no
 * need to sprinkle #ifdef into the code. Drivers which implement private ioctls
 * that require 32/64 bit compatibility support must provide their own
 * &file_operations.compat_ioctl handler that processes private ioctls and calls
 * drm_compat_ioctl() for core ioctls.
 *
 * In addition drm_read() and drm_poll() provide support for DRM events. DRM
 * events are a generic and extensible means to send asynchronous events to
 * userspace through the file descriptor. They are used to send vblank event and
 * page flip completions by the KMS API. But drivers can also use it for their
 * own needs, e.g. to signal completion of rendering.
 *
 * For the driver-side event interface see drm_event_reserve_init() and
 * drm_send_event() as the main starting points.
 *
 * The memory mapping implementation will vary depending on how the driver
 * manages memory. Legacy drivers will use the deprecated drm_legacy_mmap()
 * function, modern drivers should use one of the provided memory-manager
 * specific implementations. For GEM-based drivers this is drm_gem_mmap(), and
 * for drivers which use the CMA GEM helpers it's drm_gem_cma_mmap().
 *
 * No other file operations are supported by the DRM userspace API. Overall the
 * following is an example &file_operations structure::
 *
 *     static const example_drm_fops = {
 *             .owner = THIS_MODULE,
 *             .open = drm_open,
 *             .release = drm_release,
 *             .unlocked_ioctl = drm_ioctl,
 *             .compat_ioctl = drm_compat_ioctl, // NULL if CONFIG_COMPAT=n
 *             .poll = drm_poll,
 *             .read = drm_read,
 *             .llseek = no_llseek,
 *             .mmap = drm_gem_mmap,
 *     };
 *
 * For plain GEM based drivers there is the DEFINE_DRM_GEM_FOPS() macro, and for
 * CMA based drivers there is the DEFINE_DRM_GEM_CMA_FOPS() macro to make this
 * simpler.
 *
 * The driver's &file_operations must be stored in &drm_driver.fops.
 *
 * For driver-private IOCTL handling see the more detailed discussion in
 * :ref:`IOCTL support in the userland interfaces chapter<drm_driver_ioctl>`.
 */

/**
 * drm_file_alloc - allocate file context
 * @minor: minor to allocate on
 *
 * This allocates a new DRM file context. It is not linked into any context and
 * can be used by the caller freely. Note that the context keeps a pointer to
 * @minor, so it must be freed before @minor is.
 *
 * RETURNS:
 * Pointer to newly allocated context, ERR_PTR on failure.
 */
struct drm_file *drm_file_alloc(struct drm_minor *minor)
{
    struct drm_device *dev = minor->dev;
    struct drm_file *file;
    int ret;

    file = kzalloc(sizeof(*file), GFP_KERNEL);
    if (!file) {
        return ERR_PTR(-ENOMEM);
    }

    file->pid = get_pid(task_pid(current));
    file->minor = minor;

    /* for compatibility root is always authenticated */
    file->authenticated = capable(CAP_SYS_ADMIN);

    INIT_LIST_HEAD(&file->lhead);
    INIT_LIST_HEAD(&file->fbs);
    mutex_init(&file->fbs_lock);
    INIT_LIST_HEAD(&file->blobs);
    INIT_LIST_HEAD(&file->pending_event_list);
    INIT_LIST_HEAD(&file->event_list);
    init_waitqueue_head(&file->event_wait);
    file->event_space = 0x1000; /* set aside 4k for event buffer */

    mutex_init(&file->event_read_lock);

    if (drm_core_check_feature(dev, DRIVER_GEM)) {
        drm_gem_open(dev, file);
    }

    if (drm_core_check_feature(dev, DRIVER_SYNCOBJ)) {
        drm_syncobj_open(file);
    }

    drm_prime_init_file_private(&file->prime);

    if (dev->driver->open) {
        ret = dev->driver->open(dev, file);
        if (ret < 0) {
            goto out_prime_destroy;
        }
    }

    return file;

out_prime_destroy:
    drm_prime_destroy_file_private(&file->prime);
    if (drm_core_check_feature(dev, DRIVER_SYNCOBJ)) {
        drm_syncobj_release(file);
    }
    if (drm_core_check_feature(dev, DRIVER_GEM)) {
        drm_gem_release(dev, file);
    }
    put_pid(file->pid);
    kfree(file);

    return ERR_PTR(ret);
}

static void drm_events_release(struct drm_file *file_priv)
{
    struct drm_device *dev = file_priv->minor->dev;
    struct drm_pending_event *e, *et;
    unsigned long flags;

    spin_lock_irqsave(&dev->event_lock, flags);

    /* Unlink pending events */
    list_for_each_entry_safe(e, et, &file_priv->pending_event_list, pending_link)
    {
        list_del(&e->pending_link);
        e->file_priv = NULL;
    }

    /* Remove unconsumed events */
    list_for_each_entry_safe(e, et, &file_priv->event_list, link)
    {
        list_del(&e->link);
        kfree(e);
    }

    spin_unlock_irqrestore(&dev->event_lock, flags);
}

/**
 * drm_file_free - free file context
 * @file: context to free, or NULL
 *
 * This destroys and deallocates a DRM file context previously allocated via
 * drm_file_alloc(). The caller must make sure to unlink it from any contexts
 * before calling this.
 *
 * If NULL is passed, this is a no-op.
 *
 * RETURNS:
 * 0 on success, or error code on failure.
 */
void drm_file_free(struct drm_file *file)
{
    struct drm_device *dev;

    if (!file) {
        return;
    }

    dev = file->minor->dev;

    DRM_DEBUG("comm=\"%s\", pid=%d, dev=0x%lx, open_count=%d\n", current->comm, task_pid_nr(current),
              (long)old_encode_dev(file->minor->kdev->devt), atomic_read(&dev->open_count));

    if (drm_core_check_feature(dev, DRIVER_LEGACY) && dev->driver->preclose) {
        dev->driver->preclose(dev, file);
    }

    if (drm_core_check_feature(dev, DRIVER_LEGACY)) {
        drm_legacy_lock_release(dev, file->filp);
    }

    if (drm_core_check_feature(dev, DRIVER_HAVE_DMA)) {
        drm_legacy_reclaim_buffers(dev, file);
    }

    drm_events_release(file);

    if (drm_core_check_feature(dev, DRIVER_MODESET)) {
        drm_fb_release(file);
        drm_property_destroy_user_blobs(dev, file);
    }

    if (drm_core_check_feature(dev, DRIVER_SYNCOBJ)) {
        drm_syncobj_release(file);
    }

    if (drm_core_check_feature(dev, DRIVER_GEM)) {
        drm_gem_release(dev, file);
    }

    drm_legacy_ctxbitmap_flush(dev, file);

    if (drm_is_primary_client(file)) {
        drm_master_release(file);
    }

    if (dev->driver->postclose) {
        dev->driver->postclose(dev, file);
    }

    drm_prime_destroy_file_private(&file->prime);

    WARN_ON(!list_empty(&file->event_list));

    put_pid(file->pid);
    kfree(file);
}

static void drm_close_helper(struct file *filp)
{
    struct drm_file *file_priv = filp->private_data;
    struct drm_device *dev = file_priv->minor->dev;

    mutex_lock(&dev->filelist_mutex);
    list_del(&file_priv->lhead);
    mutex_unlock(&dev->filelist_mutex);

    drm_file_free(file_priv);
}

/*
 * Check whether DRI will run on this CPU.
 *
 * \return non-zero if the DRI will run on this CPU, or zero otherwise.
 */
static int drm_cpu_valid(void)
{
#if defined(__sparc__) && !defined(__sparc_v9__)
    return 0; /* No cmpxchg before v9 sparc. */
#endif
    return 1;
}

/*
 * Called whenever a process opens a drm node
 *
 * \param filp file pointer.
 * \param minor acquired minor-object.
 * \return zero on success or a negative number on failure.
 *
 * Creates and initializes a drm_file structure for the file private data in \p
 * filp and add it into the double linked list in \p dev.
 */
static int drm_open_helper(struct file *filp, struct drm_minor *minor)
{
    struct drm_device *dev = minor->dev;
    struct drm_file *priv;
    int ret;

    if (filp->f_flags & O_EXCL) {
        return -EBUSY; /* No exclusive opens */
    }
    if (!drm_cpu_valid()) {
        return -EINVAL;
    }
    if (dev->switch_power_state != DRM_SWITCH_POWER_ON && dev->switch_power_state != DRM_SWITCH_POWER_DYNAMIC_OFF) {
        return -EINVAL;
    }

    DRM_DEBUG("comm=\"%s\", pid=%d, minor=%d\n", current->comm, task_pid_nr(current), minor->index);

    priv = drm_file_alloc(minor);
    if (IS_ERR(priv)) {
        return PTR_ERR(priv);
    }

    if (drm_is_primary_client(priv)) {
        ret = drm_master_open(priv);
        if (ret) {
            drm_file_free(priv);
            return ret;
        }
    }

    filp->private_data = priv;
    filp->f_mode |= FMODE_UNSIGNED_OFFSET;
    priv->filp = filp;

    mutex_lock(&dev->filelist_mutex);
    list_add(&priv->lhead, &dev->filelist);
    mutex_unlock(&dev->filelist_mutex);

#ifdef __alpha__
    /*
     * Default the hose
     */
    if (!dev->hose) {
        struct pci_dev *pci_dev;

        pci_dev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 0x8, NULL);
        if (pci_dev) {
            dev->hose = pci_dev->sysdata;
            pci_dev_put(pci_dev);
        }
        if (!dev->hose) {
            struct pci_bus *b = list_entry(pci_root_buses.next, struct pci_bus, node);
            if (b) {
                dev->hose = b->sysdata;
            }
        }
    }
#endif

    return 0;
}

/**
 * drm_open - open method for DRM file
 * @inode: device inode
 * @filp: file pointer.
 *
 * This function must be used by drivers as their &file_operations.open method.
 * It looks up the correct DRM device and instantiates all the per-file
 * resources for it. It also calls the &drm_driver.open driver callback.
 *
 * RETURNS: int
 *
 * 0 on success or negative errno value on falure.
 */
int drm_open(struct inode *inode, struct file *filp)
{
    struct drm_device *dev;
    struct drm_minor *minor;
    int retcode;
    int need_setup = 0;

    minor = drm_minor_acquire(iminor(inode));
    if (IS_ERR(minor)) {
        return PTR_ERR(minor);
    }

    dev = minor->dev;
    if (drm_dev_needs_global_mutex(dev)) {
        mutex_lock(&drm_global_mutex);
    }

    if (!atomic_fetch_inc(&dev->open_count)) {
        need_setup = 1;
    }

    /* share address_space across all char-devs of a single device */
    filp->f_mapping = dev->anon_inode->i_mapping;

    retcode = drm_open_helper(filp, minor);
    if (retcode) {
        goto err_undo;
    }
    if (need_setup) {
        retcode = drm_legacy_setup(dev);
        if (retcode) {
            drm_close_helper(filp);
            goto err_undo;
        }
    }

    if (drm_dev_needs_global_mutex(dev)) {
        mutex_unlock(&drm_global_mutex);
    }

    return 0;

err_undo:
    atomic_dec(&dev->open_count);
    if (drm_dev_needs_global_mutex(dev)) {
        mutex_unlock(&drm_global_mutex);
    }
    drm_minor_release(minor);
    return retcode;
}
EXPORT_SYMBOL(drm_open);

void drm_lastclose(struct drm_device *dev)
{
    DRM_DEBUG("\n");

    if (dev->driver->lastclose) {
        dev->driver->lastclose(dev);
    }
    DRM_DEBUG("driver lastclose completed\n");

    if (drm_core_check_feature(dev, DRIVER_LEGACY)) {
        drm_legacy_dev_reinit(dev);
    }

    drm_client_dev_restore(dev);
}

/**
 * drm_release - release method for DRM file
 * @inode: device inode
 * @filp: file pointer.
 *
 * This function must be used by drivers as their &file_operations.release
 * method. It frees any resources associated with the open file, and calls the
 * &drm_driver.postclose driver callback. If this is the last open file for the
 * DRM device also proceeds to call the &drm_driver.lastclose driver callback.
 *
 * RETURNS:int
 *
 * Always succeeds and returns 0.
 */
int drm_release(struct inode *inode, struct file *filp)
{
    struct drm_file *file_priv = filp->private_data;
    struct drm_minor *minor = file_priv->minor;
    struct drm_device *dev = minor->dev;

    if (drm_dev_needs_global_mutex(dev)) {
        mutex_lock(&drm_global_mutex);
    }

    DRM_DEBUG("open_count = %d\n", atomic_read(&dev->open_count));

    drm_close_helper(filp);

    if (atomic_dec_and_test(&dev->open_count)) {
        drm_lastclose(dev);
    }

    if (drm_dev_needs_global_mutex(dev)) {
        mutex_unlock(&drm_global_mutex);
    }

    drm_minor_release(minor);

    return 0;
}
EXPORT_SYMBOL(drm_release);

/**
 * drm_release_noglobal - release method for DRM file
 * @inode: device inode
 * @filp: file pointer.
 *
 * This function may be used by drivers as their &file_operations.release
 * method. It frees any resources associated with the open file prior to taking
 * the drm_global_mutex, which then calls the &drm_driver.postclose driver
 * callback. If this is the last open file for the DRM device also proceeds to
 * call the &drm_driver.lastclose driver callback.
 *
 * RETURNS:int
 *
 * Always succeeds and returns 0.
 */
int drm_release_noglobal(struct inode *inode, struct file *filp)
{
    struct drm_file *file_priv = filp->private_data;
    struct drm_minor *minor = file_priv->minor;
    struct drm_device *dev = minor->dev;

    drm_close_helper(filp);

    if (atomic_dec_and_mutex_lock(&dev->open_count, &drm_global_mutex)) {
        drm_lastclose(dev);
        mutex_unlock(&drm_global_mutex);
    }

    drm_minor_release(minor);

    return 0;
}
EXPORT_SYMBOL(drm_release_noglobal);

/**
 * drm_read - read method for DRM file
 * @filp: file pointer
 * @buffer: userspace destination pointer for the read
 * @count: count in bytes to read
 * @offset: offset to read
 *
 * This function must be used by drivers as their &file_operations.read
 * method iff they use DRM events for asynchronous signalling to userspace.
 * Since events are used by the KMS API for vblank and page flip completion this
 * means all modern display drivers must use it.
 *
 * @offset is ignored, DRM events are read like a pipe. Therefore drivers also
 * must set the &file_operation.llseek to no_llseek(). Polling support is
 * provided by drm_poll().
 *
 * This function will only ever read a full event. Therefore userspace must
 * supply a big enough buffer to fit any event to ensure forward progress. Since
 * the maximum event space is currently 4K it's recommended to just use that for
 * safety.
 *
 * RETURNS:
 *
 * Number of bytes read (always aligned to full events, and can be 0) or a
 * negative error code on failure.
 */
ssize_t drm_read(struct file *filp, char __user *buffer, size_t count, loff_t *offset)
{
    struct drm_file *file_priv = filp->private_data;
    struct drm_device *dev = file_priv->minor->dev;
    ssize_t ret;

    ret = mutex_lock_interruptible(&file_priv->event_read_lock);
    if (ret) {
        return ret;
    }

    for (;;) {
        struct drm_pending_event *e = NULL;

        spin_lock_irq(&dev->event_lock);
        if (!list_empty(&file_priv->event_list)) {
            e = list_first_entry(&file_priv->event_list, struct drm_pending_event, link);
            file_priv->event_space += e->event->length;
            list_del(&e->link);
        }
        spin_unlock_irq(&dev->event_lock);

        if (e == NULL) {
            if (ret) {
                break;
            }

            if (filp->f_flags & O_NONBLOCK) {
                ret = -EAGAIN;
                break;
            }

            mutex_unlock(&file_priv->event_read_lock);
            ret = wait_event_interruptible(file_priv->event_wait, !list_empty(&file_priv->event_list));
            if (ret >= 0) {
                ret = mutex_lock_interruptible(&file_priv->event_read_lock);
            }
            if (ret) {
                return ret;
            }
        } else {
            unsigned length = e->event->length;

            if (length > count - ret) {

                spin_lock_irq(&dev->event_lock);
                file_priv->event_space -= length;
                list_add(&e->link, &file_priv->event_list);
                spin_unlock_irq(&dev->event_lock);
                wake_up_interruptible_poll(&file_priv->event_wait, EPOLLIN | EPOLLRDNORM);
                break;
            }

            if (copy_to_user(buffer + ret, e->event, length)) {
                if (ret == 0) {
                    ret = -EFAULT;
                }
                spin_lock_irq(&dev->event_lock);
                file_priv->event_space -= length;
                list_add(&e->link, &file_priv->event_list);
                spin_unlock_irq(&dev->event_lock);
                wake_up_interruptible_poll(&file_priv->event_wait, EPOLLIN | EPOLLRDNORM);
                break;
            }

            ret += length;
            kfree(e);
        }
    }
    mutex_unlock(&file_priv->event_read_lock);

    return ret;
}
EXPORT_SYMBOL(drm_read);

/**
 * drm_poll - poll method for DRM file
 * @filp: file pointer
 * @wait: poll waiter table
 *
 * This function must be used by drivers as their &file_operations.read method
 * iff they use DRM events for asynchronous signalling to userspace.  Since
 * events are used by the KMS API for vblank and page flip completion this means
 * all modern display drivers must use it.
 *
 * See also drm_read().
 *
 * RETURNS:int
 *
 * Mask of POLL flags indicating the current status of the file.
 */
__poll_t drm_poll(struct file *filp, struct poll_table_struct *wait)
{
    struct drm_file *file_priv = filp->private_data;
    __poll_t mask = 0;

    poll_wait(filp, &file_priv->event_wait, wait);

    if (!list_empty(&file_priv->event_list)) {
        mask |= EPOLLIN | EPOLLRDNORM;
    }

    return mask;
}
EXPORT_SYMBOL(drm_poll);

/**
 * drm_event_reserve_init_locked - init a DRM event and reserve space for it
 * @dev: DRM device
 * @file_priv: DRM file private data
 * @p: tracking structure for the pending event
 * @e: actual event data to deliver to userspace
 *
 * This function prepares the passed in event for eventual delivery. If the event
 * doesn't get delivered (because the IOCTL fails later on, before queuing up
 * anything) then the even must be cancelled and freed using
 * drm_event_cancel_free(). Successfully initialized events should be sent out
 * using drm_send_event() or drm_send_event_locked() to signal completion of the
 * asynchronous event to userspace.
 *
 * If callers embedded @p into a larger structure it must be allocated with
 * kmalloc and @p must be the first member element.
 *
 * This is the locked version of drm_event_reserve_init() for callers which
 * already hold &drm_device.event_lock.
 *
 * RETURNS:int
 *
 * 0 on success or a negative error code on failure.
 */
int drm_event_reserve_init_locked(struct drm_device *dev, struct drm_file *file_priv, struct drm_pending_event *p,
                                  struct drm_event *e)
{
    if (file_priv->event_space < e->length) {
        return -ENOMEM;
    }

    file_priv->event_space -= e->length;

    p->event = e;
    list_add(&p->pending_link, &file_priv->pending_event_list);
    p->file_priv = file_priv;

    return 0;
}
EXPORT_SYMBOL(drm_event_reserve_init_locked);

/**
 * drm_event_reserve_init - init a DRM event and reserve space for it
 * @dev: DRM device
 * @file_priv: DRM file private data
 * @p: tracking structure for the pending event
 * @e: actual event data to deliver to userspace
 *
 * This function prepares the passed in event for eventual delivery. If the event
 * doesn't get delivered (because the IOCTL fails later on, before queuing up
 * anything) then the even must be cancelled and freed using
 * drm_event_cancel_free(). Successfully initialized events should be sent out
 * using drm_send_event() or drm_send_event_locked() to signal completion of the
 * asynchronous event to userspace.
 *
 * If callers embedded @p into a larger structure it must be allocated with
 * kmalloc and @p must be the first member element.
 *
 * Callers which already hold &drm_device.event_lock should use
 * drm_event_reserve_init_locked() instead.
 *
 * RETURNS:int
 *
 * 0 on success or a negative error code on failure.
 */
int drm_event_reserve_init(struct drm_device *dev, struct drm_file *file_priv, struct drm_pending_event *p,
                           struct drm_event *e)
{
    unsigned long flags;
    int ret;

    spin_lock_irqsave(&dev->event_lock, flags);
    ret = drm_event_reserve_init_locked(dev, file_priv, p, e);
    spin_unlock_irqrestore(&dev->event_lock, flags);

    return ret;
}
EXPORT_SYMBOL(drm_event_reserve_init);

/**
 * drm_event_cancel_free - free a DRM event and release its space
 * @dev: DRM device
 * @p: tracking structure for the pending event
 *
 * This function frees the event @p initialized with drm_event_reserve_init()
 * and releases any allocated space. It is used to cancel an event when the
 * nonblocking operation could not be submitted and needed to be aborted.
 */
void drm_event_cancel_free(struct drm_device *dev, struct drm_pending_event *p)
{
    unsigned long flags;

    spin_lock_irqsave(&dev->event_lock, flags);
    if (p->file_priv) {
        p->file_priv->event_space += p->event->length;
        list_del(&p->pending_link);
    }
    spin_unlock_irqrestore(&dev->event_lock, flags);

    if (p->fence) {
        dma_fence_put(p->fence);
    }

    kfree(p);
}
EXPORT_SYMBOL(drm_event_cancel_free);

/**
 * drm_send_event_helper - send DRM event to file descriptor
 * @dev: DRM device
 * @e: DRM event to deliver
 * @timestamp: timestamp to set for the fence event in kernel's CLOCK_MONOTONIC
 * time domain
 *
 * This helper function sends the event @e, initialized with
 * drm_event_reserve_init(), to its associated userspace DRM file.
 * The timestamp variant of dma_fence_signal is used when the caller
 * sends a valid timestamp.
 */
void drm_send_event_helper(struct drm_device *dev, struct drm_pending_event *e, ktime_t timestamp)
{
    assert_spin_locked(&dev->event_lock);

    if (e->completion) {
        complete_all(e->completion);
        e->completion_release(e->completion);
        e->completion = NULL;
    }

    if (e->fence) {
        if (timestamp) {
            dma_fence_signal_timestamp(e->fence, timestamp);
        } else {
            dma_fence_signal(e->fence);
        }
        dma_fence_put(e->fence);
    }

    if (!e->file_priv) {
        kfree(e);
        return;
    }

    list_del(&e->pending_link);
    list_add_tail(&e->link, &e->file_priv->event_list);
    wake_up_interruptible_poll(&e->file_priv->event_wait, EPOLLIN | EPOLLRDNORM);
}

/**
 * drm_send_event_timestamp_locked - send DRM event to file descriptor
 * @dev: DRM device
 * @e: DRM event to deliver
 * @timestamp: timestamp to set for the fence event in kernel's CLOCK_MONOTONIC
 * time domain
 *
 * This function sends the event @e, initialized with drm_event_reserve_init(),
 * to its associated userspace DRM file. Callers must already hold
 * &drm_device.event_lock.
 *
 * Note that the core will take care of unlinking and disarming events when the
 * corresponding DRM file is closed. Drivers need not worry about whether the
 * DRM file for this event still exists and can call this function upon
 * completion of the asynchronous work unconditionally.
 */
void drm_send_event_timestamp_locked(struct drm_device *dev, struct drm_pending_event *e, ktime_t timestamp)
{
    drm_send_event_helper(dev, e, timestamp);
}
EXPORT_SYMBOL(drm_send_event_timestamp_locked);

/**
 * drm_send_event_locked - send DRM event to file descriptor
 * @dev: DRM device
 * @e: DRM event to deliver
 *
 * This function sends the event @e, initialized with drm_event_reserve_init(),
 * to its associated userspace DRM file. Callers must already hold
 * &drm_device.event_lock, see drm_send_event() for the unlocked version.
 *
 * Note that the core will take care of unlinking and disarming events when the
 * corresponding DRM file is closed. Drivers need not worry about whether the
 * DRM file for this event still exists and can call this function upon
 * completion of the asynchronous work unconditionally.
 */
void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e)
{
    drm_send_event_helper(dev, e, 0);
}
EXPORT_SYMBOL(drm_send_event_locked);

/**
 * drm_send_event - send DRM event to file descriptor
 * @dev: DRM device
 * @e: DRM event to deliver
 *
 * This function sends the event @e, initialized with drm_event_reserve_init(),
 * to its associated userspace DRM file. This function acquires
 * &drm_device.event_lock, see drm_send_event_locked() for callers which already
 * hold this lock.
 *
 * Note that the core will take care of unlinking and disarming events when the
 * corresponding DRM file is closed. Drivers need not worry about whether the
 * DRM file for this event still exists and can call this function upon
 * completion of the asynchronous work unconditionally.
 */
void drm_send_event(struct drm_device *dev, struct drm_pending_event *e)
{
    unsigned long irqflags;

    spin_lock_irqsave(&dev->event_lock, irqflags);
    drm_send_event_helper(dev, e, 0);
    spin_unlock_irqrestore(&dev->event_lock, irqflags);
}
EXPORT_SYMBOL(drm_send_event);

/**
 * mock_drm_getfile - Create a new struct file for the drm device
 * @minor: drm minor to wrap (e.g. #drm_device.primary)
 * @flags: file creation mode (O_RDWR etc)
 *
 * This create a new struct file that wraps a DRM file context around a
 * DRM minor. This mimicks userspace opening e.g. /dev/dri/card0, but without
 * invoking userspace. The struct file may be operated on using its f_op
 * (the drm_device.driver.fops) to mimick userspace operations, or be supplied
 * to userspace facing functions as an internal/anonymous client.
 *
 * RETURNS:
 * Pointer to newly created struct file, ERR_PTR on failure.
 */
struct file *mock_drm_getfile(struct drm_minor *minor, unsigned int flags)
{
    struct drm_device *dev = minor->dev;
    struct drm_file *priv;
    struct file *file;

    priv = drm_file_alloc(minor);
    if (IS_ERR(priv)) {
        return ERR_CAST(priv);
    }

    file = anon_inode_getfile("drm", dev->driver->fops, priv, flags);
    if (IS_ERR(file)) {
        drm_file_free(priv);
        return file;
    }

    /* Everyone shares a single global address space */
    file->f_mapping = dev->anon_inode->i_mapping;

    drm_dev_get(dev);
    priv->filp = file;

    return file;
}
EXPORT_SYMBOL_FOR_TESTS_ONLY(mock_drm_getfile);

#ifdef CONFIG_MMU
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
 * drm_addr_inflate() attempts to construct an aligned area by inflating
 * the area size and skipping the unaligned start of the area.
 * adapted from shmem_get_unmapped_area()
 */
static unsigned long drm_addr_inflate(unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags,
                                      unsigned long huge_size)
{
    unsigned long offset, inflated_len;
    unsigned long inflated_addr;
    unsigned long inflated_offset;

    offset = (pgoff << PAGE_SHIFT) & (huge_size - 1);
    if (offset && offset + len < 0x2 * huge_size) {
        return addr;
    }
    if ((addr & (huge_size - 1)) == offset) {
        return addr;
    }

    inflated_len = len + huge_size - PAGE_SIZE;
    if (inflated_len > TASK_SIZE) {
        return addr;
    }
    if (inflated_len < len) {
        return addr;
    }

    inflated_addr = current->mm->get_unmapped_area(NULL, 0, inflated_len, 0, flags);
    if (IS_ERR_VALUE(inflated_addr)) {
        return addr;
    }
    if (inflated_addr & ~PAGE_MASK) {
        return addr;
    }

    inflated_offset = inflated_addr & (huge_size - 1);
    inflated_addr += offset - inflated_offset;
    if (inflated_offset > offset) {
        inflated_addr += huge_size;
    }

    if (inflated_addr > TASK_SIZE - len) {
        return addr;
    }

    return inflated_addr;
}

/**
 * drm_get_unmapped_area() - Get an unused user-space virtual memory area
 * suitable for huge page table entries.
 * @file: The struct file representing the address space being mmap()'d.
 * @uaddr: Start address suggested by user-space.
 * @len: Length of the area.
 * @pgoff: The page offset into the address space.
 * @flags: mmap flags
 * @mgr: The address space manager used by the drm driver. This argument can
 * probably be removed at some point when all drivers use the same
 * address space manager.
 *
 * This function attempts to find an unused user-space virtual memory area
 * that can accommodate the size we want to map, and that is properly
 * aligned to facilitate huge page table entries matching actual
 * huge pages or huge page aligned memory in buffer objects. Buffer objects
 * are assumed to start at huge page boundary pfns (io memory) or be
 * populated by huge pages aligned to the start of the buffer object
 * (system- or coherent memory). Adapted from shmem_get_unmapped_area.
 *
 * Return: aligned user-space address.
 */
unsigned long drm_get_unmapped_area(struct file *file, unsigned long uaddr, unsigned long len, unsigned long pgoff,
                                    unsigned long flags, struct drm_vma_offset_manager *mgr)
{
    unsigned long addr;
    unsigned long inflated_addr;
    struct drm_vma_offset_node *node;

    if (len > TASK_SIZE) {
        return -ENOMEM;
    }

    /*
     * @pgoff is the file page-offset the huge page boundaries of
     * which typically aligns to physical address huge page boundaries.
     * That's not true for DRM, however, where physical address huge
     * page boundaries instead are aligned with the offset from
     * buffer object start. So adjust @pgoff to be the offset from
     * buffer object start.
     */
    drm_vma_offset_lock_lookup(mgr);
    node = drm_vma_offset_lookup_locked(mgr, pgoff, 1);
    if (node) {
        pgoff -= node->vm_node.start;
    }
    drm_vma_offset_unlock_lookup(mgr);

    addr = current->mm->get_unmapped_area(file, uaddr, len, pgoff, flags);
    if (IS_ERR_VALUE(addr)) {
        return addr;
    }
    if (addr & ~PAGE_MASK) {
        return addr;
    }
    if (addr > TASK_SIZE - len) {
        return addr;
    }

    if (len < HPAGE_PMD_SIZE) {
        return addr;
    }
    if (flags & MAP_FIXED) {
        return addr;
    }
    /*
     * Our priority is to support MAP_SHARED mapped hugely;
     * and support MAP_PRIVATE mapped hugely too, until it is COWed.
     * But if caller specified an address hint, respect that as before.
     */
    if (uaddr) {
        return addr;
    }

    inflated_addr = drm_addr_inflate(addr, len, pgoff, flags, HPAGE_PMD_SIZE);

    if (IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) && len >= HPAGE_PUD_SIZE) {
        inflated_addr = drm_addr_inflate(inflated_addr, len, pgoff, flags, HPAGE_PUD_SIZE);
    }
    return inflated_addr;
}
#else  /* CONFIG_TRANSPARENT_HUGEPAGE */
unsigned long drm_get_unmapped_area(struct file *file, unsigned long uaddr, unsigned long len, unsigned long pgoff,
                                    unsigned long flags, struct drm_vma_offset_manager *mgr)
{
    return current->mm->get_unmapped_area(file, uaddr, len, pgoff, flags);
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
EXPORT_SYMBOL_GPL(drm_get_unmapped_area);
#endif /* CONFIG_MMU */