Input: extend the number of event (and other) devices
[firefly-linux-kernel-4.4.55.git] / drivers / input / evdev.c
index 118d0300f1fb72a1324006f544b790a6085affa2..6ae2ac47c9c806ecf5224e2eb02c49a704b40432 100644 (file)
 #include <linux/input/mt.h>
 #include <linux/major.h>
 #include <linux/device.h>
+#include <linux/cdev.h>
 #include "input-compat.h"
 
 struct evdev {
        int open;
-       int minor;
        struct input_handle handle;
        wait_queue_head_t wait;
        struct evdev_client __rcu *grab;
@@ -35,6 +35,7 @@ struct evdev {
        spinlock_t client_lock; /* protects client_list */
        struct mutex mutex;
        struct device dev;
+       struct cdev cdev;
        bool exist;
 };
 
@@ -51,9 +52,6 @@ struct evdev_client {
        struct input_event buffer[];
 };
 
-static struct evdev *evdev_table[EVDEV_MINORS];
-static DEFINE_MUTEX(evdev_table_mutex);
-
 static void __pass_event(struct evdev_client *client,
                         const struct input_event *event)
 {
@@ -310,35 +308,16 @@ static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 
 static int evdev_open(struct inode *inode, struct file *file)
 {
-       struct evdev *evdev;
+       struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
+       unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
        struct evdev_client *client;
-       int i = iminor(inode) - EVDEV_MINOR_BASE;
-       unsigned int bufsize;
        int error;
 
-       if (i >= EVDEV_MINORS)
-               return -ENODEV;
-
-       error = mutex_lock_interruptible(&evdev_table_mutex);
-       if (error)
-               return error;
-       evdev = evdev_table[i];
-       if (evdev)
-               get_device(&evdev->dev);
-       mutex_unlock(&evdev_table_mutex);
-
-       if (!evdev)
-               return -ENODEV;
-
-       bufsize = evdev_compute_buffer_size(evdev->handle.dev);
-
        client = kzalloc(sizeof(struct evdev_client) +
                                bufsize * sizeof(struct input_event),
                         GFP_KERNEL);
-       if (!client) {
-               error = -ENOMEM;
-               goto err_put_evdev;
-       }
+       if (!client)
+               return -ENOMEM;
 
        client->bufsize = bufsize;
        spin_lock_init(&client->buffer_lock);
@@ -352,13 +331,12 @@ static int evdev_open(struct inode *inode, struct file *file)
        file->private_data = client;
        nonseekable_open(inode, file);
 
+       get_device(&evdev->dev);
        return 0;
 
  err_free_client:
        evdev_detach_client(evdev, client);
        kfree(client);
- err_put_evdev:
-       put_device(&evdev->dev);
        return error;
 }
 
@@ -942,26 +920,6 @@ static const struct file_operations evdev_fops = {
        .llseek         = no_llseek,
 };
 
-static int evdev_install_chrdev(struct evdev *evdev)
-{
-       /*
-        * No need to do any locking here as calls to connect and
-        * disconnect are serialized by the input core
-        */
-       evdev_table[evdev->minor] = evdev;
-       return 0;
-}
-
-static void evdev_remove_chrdev(struct evdev *evdev)
-{
-       /*
-        * Lock evdev table to prevent race with evdev_open()
-        */
-       mutex_lock(&evdev_table_mutex);
-       evdev_table[evdev->minor] = NULL;
-       mutex_unlock(&evdev_table_mutex);
-}
-
 /*
  * Mark device non-existent. This disables writes, ioctls and
  * prevents new users from opening the device. Already posted
@@ -980,7 +938,8 @@ static void evdev_cleanup(struct evdev *evdev)
 
        evdev_mark_dead(evdev);
        evdev_hangup(evdev);
-       evdev_remove_chrdev(evdev);
+
+       cdev_del(&evdev->cdev);
 
        /* evdev is marked dead so no one else accesses evdev->open */
        if (evdev->open) {
@@ -991,43 +950,47 @@ static void evdev_cleanup(struct evdev *evdev)
 
 /*
  * Create new evdev device. Note that input core serializes calls
- * to connect and disconnect so we don't need to lock evdev_table here.
+ * to connect and disconnect.
  */
 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
                         const struct input_device_id *id)
 {
        struct evdev *evdev;
        int minor;
+       int dev_no;
        int error;
 
-       for (minor = 0; minor < EVDEV_MINORS; minor++)
-               if (!evdev_table[minor])
-                       break;
-
-       if (minor == EVDEV_MINORS) {
-               pr_err("no more free evdev devices\n");
-               return -ENFILE;
+       minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
+       if (minor < 0) {
+               error = minor;
+               pr_err("failed to reserve new minor: %d\n", error);
+               return error;
        }
 
        evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
-       if (!evdev)
-               return -ENOMEM;
+       if (!evdev) {
+               error = -ENOMEM;
+               goto err_free_minor;
+       }
 
        INIT_LIST_HEAD(&evdev->client_list);
        spin_lock_init(&evdev->client_lock);
        mutex_init(&evdev->mutex);
        init_waitqueue_head(&evdev->wait);
-
-       dev_set_name(&evdev->dev, "event%d", minor);
        evdev->exist = true;
-       evdev->minor = minor;
+
+       dev_no = minor;
+       /* Normalize device number if it falls into legacy range */
+       if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
+               dev_no -= EVDEV_MINOR_BASE;
+       dev_set_name(&evdev->dev, "event%d", dev_no);
 
        evdev->handle.dev = input_get_device(dev);
        evdev->handle.name = dev_name(&evdev->dev);
        evdev->handle.handler = handler;
        evdev->handle.private = evdev;
 
-       evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
+       evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
        evdev->dev.class = &input_class;
        evdev->dev.parent = &dev->dev;
        evdev->dev.release = evdev_free;
@@ -1037,7 +1000,8 @@ static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
        if (error)
                goto err_free_evdev;
 
-       error = evdev_install_chrdev(evdev);
+       cdev_init(&evdev->cdev, &evdev_fops);
+       error = cdev_add(&evdev->cdev, evdev->dev.devt, 1);
        if (error)
                goto err_unregister_handle;
 
@@ -1053,6 +1017,8 @@ static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
        input_unregister_handle(&evdev->handle);
  err_free_evdev:
        put_device(&evdev->dev);
+ err_free_minor:
+       input_free_minor(minor);
        return error;
 }
 
@@ -1062,6 +1028,7 @@ static void evdev_disconnect(struct input_handle *handle)
 
        device_del(&evdev->dev);
        evdev_cleanup(evdev);
+       input_free_minor(MINOR(evdev->dev.devt));
        input_unregister_handle(handle);
        put_device(&evdev->dev);
 }
@@ -1078,7 +1045,7 @@ static struct input_handler evdev_handler = {
        .events         = evdev_events,
        .connect        = evdev_connect,
        .disconnect     = evdev_disconnect,
-       .fops           = &evdev_fops,
+       .legacy_minors  = true,
        .minor          = EVDEV_MINOR_BASE,
        .name           = "evdev",
        .id_table       = evdev_ids,