1 files changed, 45 insertions, 1 deletions

diff --git a/include/linux/hid.h b/include/linux/hid.h
index e14b465b1146..895b85639dec 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -456,7 +456,8 @@ struct hid_device {							/* device report descriptor */
         unsigned country;                                               /* HID country */
         struct hid_report_enum report_enum[HID_REPORT_TYPES];
 
-        struct semaphore driver_lock;                                   /* protects the current driver */
+        struct semaphore driver_lock;                                   /* protects the current driver, except during input */
+        struct semaphore driver_input_lock;                             /* protects the current driver */
         struct device dev;                                              /* device */
         struct hid_driver *driver;
         struct hid_ll_driver *ll_driver;
@@ -477,6 +478,7 @@ struct hid_device {							/* device report descriptor */
         unsigned int status;                                            /* see STAT flags above */
         unsigned claimed;                                               /* Claimed by hidinput, hiddev? */
         unsigned quirks;                                                /* Various quirks the device can pull on us */
+        bool io_started;                                                /* Protected by driver_lock. If IO has started */
 
         struct list_head inputs;                                        /* The list of inputs */
         void *hiddev;                                                   /* The hiddev structure */
@@ -599,6 +601,10 @@ struct hid_usage_id {
  * @resume: invoked on resume if device was not reset (NULL means nop)
  * @reset_resume: invoked on resume if device was reset (NULL means nop)
  *
+ * probe should return -errno on error, or 0 on success. During probe,
+ * input will not be passed to raw_event unless hid_device_io_start is
+ * called.
+ *
  * raw_event and event should return 0 on no action performed, 1 when no
  * further processing should be done and negative on error
  *
@@ -738,6 +744,44 @@ const struct hid_device_id *hid_match_id(struct hid_device *hdev,
 s32 hid_snto32(__u32 value, unsigned n);
 
 /**
+ * hid_device_io_start - enable HID input during probe, remove
+ *
+ * @hid - the device
+ *
+ * This should only be called during probe or remove and only be
+ * called by the thread calling probe or remove. It will allow
+ * incoming packets to be delivered to the driver.
+ */
+static inline void hid_device_io_start(struct hid_device *hid) {
+        if (hid->io_started) {
+                dev_warn(&hid->dev, "io already started");
+                return;
+        }
+        hid->io_started = true;
+        up(&hid->driver_input_lock);
+}
+
+/**
+ * hid_device_io_stop - disable HID input during probe, remove
+ *
+ * @hid - the device
+ *
+ * Should only be called after hid_device_io_start. It will prevent
+ * incoming packets from going to the driver for the duration of
+ * probe, remove. If called during probe, packets will still go to the
+ * driver after probe is complete. This function should only be called
+ * by the thread calling probe or remove.
+ */
+static inline void hid_device_io_stop(struct hid_device *hid) {
+        if (!hid->io_started) {
+                dev_warn(&hid->dev, "io already stopped");
+                return;
+        }
+        hid->io_started = false;
+        down(&hid->driver_input_lock);
+}
+
+/**
  * hid_map_usage - map usage input bits
  *
  * @hidinput: hidinput which we are interested in