platform/x86: wmi: Remove chardev interface
The design of the WMI chardev interface is broken: - it assumes that WMI drivers are not instantiated twice - it offers next to no abstractions, the WMI driver gets a raw byte buffer - it is only used by a single driver, something which is unlikely to change Since the only user (dell-smbios-wmi) has been migrated to his own ioctl interface, remove it. Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Armin Wolf <W_Armin@gmx.de> Link: https://lore.kernel.org/r/20231210202443.646427-6-W_Armin@gmx.de Reviewed-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
This commit is contained in:
Armin Wolf
Hans de Goede
parent
93885e85a7
commit
704af3a407
2 changed files with 5 additions and 183 deletions
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@ -23,17 +23,14 @@
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/sysfs.h>
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#include <linux/types.h>
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#include <linux/uaccess.h>
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#include <linux/uuid.h>
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#include <linux/wmi.h>
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#include <linux/fs.h>
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#include <uapi/linux/wmi.h>
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MODULE_AUTHOR("Carlos Corbacho");
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MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
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@ -66,12 +63,9 @@ struct wmi_block {
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struct wmi_device dev;
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struct list_head list;
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struct guid_block gblock;
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struct miscdevice char_dev;
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struct mutex char_mutex;
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struct acpi_device *acpi_device;
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wmi_notify_handler handler;
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void *handler_data;
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u64 req_buf_size;
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unsigned long flags;
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};
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@ -256,26 +250,6 @@ static void wmi_device_put(struct wmi_device *wdev)
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* Exported WMI functions
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*/
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/**
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* set_required_buffer_size - Sets the buffer size needed for performing IOCTL
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* @wdev: A wmi bus device from a driver
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* @length: Required buffer size
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*
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* Allocates memory needed for buffer, stores the buffer size in that memory.
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*
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* Return: 0 on success or a negative error code for failure.
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*/
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int set_required_buffer_size(struct wmi_device *wdev, u64 length)
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{
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struct wmi_block *wblock;
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wblock = container_of(wdev, struct wmi_block, dev);
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wblock->req_buf_size = length;
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return 0;
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}
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EXPORT_SYMBOL_GPL(set_required_buffer_size);
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/**
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* wmi_instance_count - Get number of WMI object instances
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* @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
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@ -884,111 +858,12 @@ static int wmi_dev_match(struct device *dev, struct device_driver *driver)
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return 0;
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}
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static int wmi_char_open(struct inode *inode, struct file *filp)
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{
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/*
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* The miscdevice already stores a pointer to itself
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* inside filp->private_data
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*/
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struct wmi_block *wblock = container_of(filp->private_data, struct wmi_block, char_dev);
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filp->private_data = wblock;
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return nonseekable_open(inode, filp);
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}
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static ssize_t wmi_char_read(struct file *filp, char __user *buffer,
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size_t length, loff_t *offset)
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{
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struct wmi_block *wblock = filp->private_data;
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return simple_read_from_buffer(buffer, length, offset,
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&wblock->req_buf_size,
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sizeof(wblock->req_buf_size));
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}
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static long wmi_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
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{
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struct wmi_ioctl_buffer __user *input =
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(struct wmi_ioctl_buffer __user *) arg;
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struct wmi_block *wblock = filp->private_data;
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struct wmi_ioctl_buffer *buf;
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struct wmi_driver *wdriver;
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int ret;
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if (_IOC_TYPE(cmd) != WMI_IOC)
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return -ENOTTY;
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/* make sure we're not calling a higher instance than exists*/
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if (_IOC_NR(cmd) >= wblock->gblock.instance_count)
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return -EINVAL;
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mutex_lock(&wblock->char_mutex);
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buf = wblock->handler_data;
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if (get_user(buf->length, &input->length)) {
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dev_dbg(&wblock->dev.dev, "Read length from user failed\n");
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ret = -EFAULT;
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goto out_ioctl;
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}
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/* if it's too small, abort */
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if (buf->length < wblock->req_buf_size) {
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dev_err(&wblock->dev.dev,
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"Buffer %lld too small, need at least %lld\n",
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buf->length, wblock->req_buf_size);
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ret = -EINVAL;
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goto out_ioctl;
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}
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/* if it's too big, warn, driver will only use what is needed */
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if (buf->length > wblock->req_buf_size)
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dev_warn(&wblock->dev.dev,
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"Buffer %lld is bigger than required %lld\n",
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buf->length, wblock->req_buf_size);
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/* copy the structure from userspace */
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if (copy_from_user(buf, input, wblock->req_buf_size)) {
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dev_dbg(&wblock->dev.dev, "Copy %llu from user failed\n",
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wblock->req_buf_size);
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ret = -EFAULT;
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goto out_ioctl;
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}
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/* let the driver do any filtering and do the call */
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wdriver = drv_to_wdrv(wblock->dev.dev.driver);
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if (!try_module_get(wdriver->driver.owner)) {
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ret = -EBUSY;
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goto out_ioctl;
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}
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ret = wdriver->filter_callback(&wblock->dev, cmd, buf);
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module_put(wdriver->driver.owner);
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if (ret)
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goto out_ioctl;
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/* return the result (only up to our internal buffer size) */
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if (copy_to_user(input, buf, wblock->req_buf_size)) {
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dev_dbg(&wblock->dev.dev, "Copy %llu to user failed\n",
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wblock->req_buf_size);
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ret = -EFAULT;
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}
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out_ioctl:
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mutex_unlock(&wblock->char_mutex);
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return ret;
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}
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static const struct file_operations wmi_fops = {
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.owner = THIS_MODULE,
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.read = wmi_char_read,
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.open = wmi_char_open,
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.unlocked_ioctl = wmi_ioctl,
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.compat_ioctl = compat_ptr_ioctl,
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};
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static int wmi_dev_probe(struct device *dev)
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{
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struct wmi_block *wblock = dev_to_wblock(dev);
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struct wmi_driver *wdriver = drv_to_wdrv(dev->driver);
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int ret = 0;
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char *buf;
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if (ACPI_FAILURE(wmi_method_enable(wblock, true)))
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dev_warn(dev, "failed to enable device -- probing anyway\n");
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@ -996,55 +871,17 @@ static int wmi_dev_probe(struct device *dev)
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if (wdriver->probe) {
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ret = wdriver->probe(dev_to_wdev(dev),
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find_guid_context(wblock, wdriver));
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if (ret != 0)
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goto probe_failure;
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}
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if (!ret) {
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if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
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dev_warn(dev, "Failed to disable device\n");
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/* driver wants a character device made */
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if (wdriver->filter_callback) {
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/* check that required buffer size declared by driver or MOF */
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if (!wblock->req_buf_size) {
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dev_err(&wblock->dev.dev,
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"Required buffer size not set\n");
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ret = -EINVAL;
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goto probe_failure;
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}
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wblock->handler_data = kmalloc(wblock->req_buf_size,
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GFP_KERNEL);
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if (!wblock->handler_data) {
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ret = -ENOMEM;
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goto probe_failure;
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}
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buf = kasprintf(GFP_KERNEL, "wmi/%s", wdriver->driver.name);
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if (!buf) {
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ret = -ENOMEM;
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goto probe_string_failure;
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}
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wblock->char_dev.minor = MISC_DYNAMIC_MINOR;
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wblock->char_dev.name = buf;
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wblock->char_dev.fops = &wmi_fops;
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wblock->char_dev.mode = 0444;
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ret = misc_register(&wblock->char_dev);
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if (ret) {
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dev_warn(dev, "failed to register char dev: %d\n", ret);
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ret = -ENOMEM;
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goto probe_misc_failure;
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return ret;
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}
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}
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set_bit(WMI_PROBED, &wblock->flags);
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return 0;
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probe_misc_failure:
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kfree(buf);
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probe_string_failure:
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kfree(wblock->handler_data);
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probe_failure:
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if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
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dev_warn(dev, "failed to disable device\n");
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return ret;
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return 0;
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}
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static void wmi_dev_remove(struct device *dev)
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@ -1054,12 +891,6 @@ static void wmi_dev_remove(struct device *dev)
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clear_bit(WMI_PROBED, &wblock->flags);
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if (wdriver->filter_callback) {
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misc_deregister(&wblock->char_dev);
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kfree(wblock->char_dev.name);
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kfree(wblock->handler_data);
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}
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if (wdriver->remove)
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wdriver->remove(dev_to_wdev(dev));
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@ -1131,7 +962,6 @@ static int wmi_create_device(struct device *wmi_bus_dev,
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if (wblock->gblock.flags & ACPI_WMI_METHOD) {
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wblock->dev.dev.type = &wmi_type_method;
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mutex_init(&wblock->char_mutex);
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goto out_init;
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}
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@ -11,7 +11,6 @@
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#include <linux/device.h>
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#include <linux/acpi.h>
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#include <linux/mod_devicetable.h>
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#include <uapi/linux/wmi.h>
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/**
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* struct wmi_device - WMI device structure
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@ -47,8 +46,6 @@ acpi_status wmidev_block_set(struct wmi_device *wdev, u8 instance, const struct
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u8 wmidev_instance_count(struct wmi_device *wdev);
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extern int set_required_buffer_size(struct wmi_device *wdev, u64 length);
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/**
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* struct wmi_driver - WMI driver structure
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* @driver: Driver model structure
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@ -57,11 +54,8 @@ extern int set_required_buffer_size(struct wmi_device *wdev, u64 length);
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* @probe: Callback for device binding
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* @remove: Callback for device unbinding
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* @notify: Callback for receiving WMI events
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* @filter_callback: Callback for filtering device IOCTLs
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*
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* This represents WMI drivers which handle WMI devices.
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* @filter_callback is only necessary for drivers which
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* want to set up a WMI IOCTL interface.
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*/
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struct wmi_driver {
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struct device_driver driver;
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@ -71,8 +65,6 @@ struct wmi_driver {
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int (*probe)(struct wmi_device *wdev, const void *context);
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void (*remove)(struct wmi_device *wdev);
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void (*notify)(struct wmi_device *device, union acpi_object *data);
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long (*filter_callback)(struct wmi_device *wdev, unsigned int cmd,
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struct wmi_ioctl_buffer *arg);
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};
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extern int __must_check __wmi_driver_register(struct wmi_driver *driver,
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