1 files changed, 53 insertions, 61 deletions

diff --git a/drivers/input/input.c b/drivers/input/input.c
index ace3f7c4226d..53a0ddee7872 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -14,6 +14,7 @@
 
 #include <linux/init.h>
 #include <linux/types.h>
+#include <linux/idr.h>
 #include <linux/input/mt.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -32,7 +33,9 @@ MODULE_AUTHOR("Vojtech Pavlik <vojtech@suse.cz>");
 MODULE_DESCRIPTION("Input core");
 MODULE_LICENSE("GPL");
 
-#define INPUT_DEVICES   256
+#define INPUT_MAX_CHAR_DEVICES          1024
+#define INPUT_FIRST_DYNAMIC_DEV         256
+static DEFINE_IDA(input_ida);
 
 static LIST_HEAD(input_dev_list);
 static LIST_HEAD(input_handler_list);
@@ -45,8 +48,6 @@ static LIST_HEAD(input_handler_list);
  */
 static DEFINE_MUTEX(input_mutex);
 
-static struct input_handler *input_table[8];
-
 static const struct input_value input_value_sync = { EV_SYN, SYN_REPORT, 1 };
 
 static inline int is_event_supported(unsigned int code,
@@ -1218,7 +1219,7 @@ static int input_handlers_seq_show(struct seq_file *seq, void *v)
         seq_printf(seq, "N: Number=%u Name=%s", state->pos, handler->name);
         if (handler->filter)
                 seq_puts(seq, " (filter)");
-        if (handler->fops)
+        if (handler->legacy_minors)
                 seq_printf(seq, " Minor=%d", handler->minor);
         seq_putc(seq, '\n');
 
@@ -2016,22 +2017,14 @@ EXPORT_SYMBOL(input_unregister_device);
 int input_register_handler(struct input_handler *handler)
 {
         struct input_dev *dev;
-        int retval;
+        int error;
 
-        retval = mutex_lock_interruptible(&input_mutex);
-        if (retval)
-                return retval;
+        error = mutex_lock_interruptible(&input_mutex);
+        if (error)
+                return error;
 
         INIT_LIST_HEAD(&handler->h_list);
 
-        if (handler->fops != NULL) {
-                if (input_table[handler->minor >> 5]) {
-                        retval = -EBUSY;
-                        goto out;
-                }
-                input_table[handler->minor >> 5] = handler;
-        }
-
         list_add_tail(&handler->node, &input_handler_list);
 
         list_for_each_entry(dev, &input_dev_list, node)
@@ -2039,9 +2032,8 @@ int input_register_handler(struct input_handler *handler)
 
         input_wakeup_procfs_readers();
 
- out:
         mutex_unlock(&input_mutex);
-        return retval;
+        return 0;
 }
 EXPORT_SYMBOL(input_register_handler);
 
@@ -2064,9 +2056,6 @@ void input_unregister_handler(struct input_handler *handler)
 
         list_del_init(&handler->node);
 
-        if (handler->fops != NULL)
-                input_table[handler->minor >> 5] = NULL;
-
         input_wakeup_procfs_readers();
 
         mutex_unlock(&input_mutex);
@@ -2183,51 +2172,52 @@ void input_unregister_handle(struct input_handle *handle)
 }
 EXPORT_SYMBOL(input_unregister_handle);
 
-static int input_open_file(struct inode *inode, struct file *file)
+/**
+ * input_get_new_minor - allocates a new input minor number
+ * @legacy_base: beginning or the legacy range to be searched
+ * @legacy_num: size of legacy range
+ * @allow_dynamic: whether we can also take ID from the dynamic range
+ *
+ * This function allocates a new device minor for from input major namespace.
+ * Caller can request legacy minor by specifying @legacy_base and @legacy_num
+ * parameters and whether ID can be allocated from dynamic range if there are
+ * no free IDs in legacy range.
+ */
+int input_get_new_minor(int legacy_base, unsigned int legacy_num,
+                        bool allow_dynamic)
 {
-        struct input_handler *handler;
-        const struct file_operations *old_fops, *new_fops = NULL;
-        int err;
-
-        err = mutex_lock_interruptible(&input_mutex);
-        if (err)
-                return err;
-
-        /* No load-on-demand here? */
-        handler = input_table[iminor(inode) >> 5];
-        if (handler)
-                new_fops = fops_get(handler->fops);
-
-        mutex_unlock(&input_mutex);
-
         /*
-         * That's _really_ odd. Usually NULL ->open means "nothing special",
-         * not "no device". Oh, well...
+         * This function should be called from input handler's ->connect()
+         * methods, which are serialized with input_mutex, so no additional
+         * locking is needed here.
          */
-        if (!new_fops || !new_fops->open) {
-                fops_put(new_fops);
-                err = -ENODEV;
-                goto out;
+        if (legacy_base >= 0) {
+                int minor = ida_simple_get(&input_ida,
+                                           legacy_base,
+                                           legacy_base + legacy_num,
+                                           GFP_KERNEL);
+                if (minor >= 0 || !allow_dynamic)
+                        return minor;
         }
 
-        old_fops = file->f_op;
-        file->f_op = new_fops;
-
-        err = new_fops->open(inode, file);
-        if (err) {
-                fops_put(file->f_op);
-                file->f_op = fops_get(old_fops);
-        }
-        fops_put(old_fops);
-out:
-        return err;
+        return ida_simple_get(&input_ida,
+                              INPUT_FIRST_DYNAMIC_DEV, INPUT_MAX_CHAR_DEVICES,
+                              GFP_KERNEL);
 }
+EXPORT_SYMBOL(input_get_new_minor);
 
-static const struct file_operations input_fops = {
-        .owner = THIS_MODULE,
-        .open = input_open_file,
-        .llseek = noop_llseek,
-};
+/**
+ * input_free_minor - release previously allocated minor
+ * @minor: minor to be released
+ *
+ * This function releases previously allocated input minor so that it can be
+ * reused later.
+ */
+void input_free_minor(unsigned int minor)
+{
+        ida_simple_remove(&input_ida, minor);
+}
+EXPORT_SYMBOL(input_free_minor);
 
 static int __init input_init(void)
 {
@@ -2243,7 +2233,8 @@ static int __init input_init(void)
         if (err)
                 goto fail1;
 
-        err = register_chrdev(INPUT_MAJOR, "input", &input_fops);
+        err = register_chrdev_region(MKDEV(INPUT_MAJOR, 0),
+                                     INPUT_MAX_CHAR_DEVICES, "input");
         if (err) {
                 pr_err("unable to register char major %d", INPUT_MAJOR);
                 goto fail2;
@@ -2259,7 +2250,8 @@ static int __init input_init(void)
 static void __exit input_exit(void)
 {
         input_proc_exit();
-        unregister_chrdev(INPUT_MAJOR, "input");
+        unregister_chrdev_region(MKDEV(INPUT_MAJOR, 0),
+                                 INPUT_MAX_CHAR_DEVICES);
         class_unregister(&input_class);
 }