Bluetooth: hidp: Stop I/O on shutdown

Current hidp driver purges the in/out queue on HID shutdown, but does
not prevent further I/O. If a driver uses hidp_output_raw_report or
hidp_get_raw_report during shutdown, the driver hangs for 5 or 10
seconds per call until it gets a timeout.
That is, if the output queue of an HID driver has 10 messages pending,
it will take 50s until hid_destroy_device() will return. The
hidp_session_sem semaphore is held during shutdown so no other HID
device may be added/removed during this time.

This patch makes hidp_output_raw_report and hidp_get_raw_report fail if
session->terminate is true. Also hidp_session will wakeup all current
calls to these functions to cancel the current operations.

We already purge the current I/O queues on hidp_stop(), so this data loss
does not change the behaviour of the HID drivers.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index 075a3e9..d7bae2b 100644 (file)
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -255,6 +255,9 @@ static int __hidp_send_ctrl_message(struct hidp_session *session,
 
        BT_DBG("session %p data %p size %d", session, data, size);
 
+       if (atomic_read(&session->terminate))
+               return -EIO;
+
        skb = alloc_skb(size + 1, GFP_ATOMIC);
        if (!skb) {
                BT_ERR("Can't allocate memory for new frame");
@@ -329,6 +332,7 @@ static int hidp_get_raw_report(struct hid_device *hid,
        struct sk_buff *skb;
        size_t len;
        int numbered_reports = hid->report_enum[report_type].numbered;
+       int ret;
 
        switch (report_type) {
        case HID_FEATURE_REPORT:
@@ -352,8 +356,9 @@ static int hidp_get_raw_report(struct hid_device *hid,
        session->waiting_report_number = numbered_reports ? report_number : -1;
        set_bit(HIDP_WAITING_FOR_RETURN, &session->flags);
        data[0] = report_number;
-       if (hidp_send_ctrl_message(hid->driver_data, report_type, data, 1))
-               goto err_eio;
+       ret = hidp_send_ctrl_message(hid->driver_data, report_type, data, 1);
+       if (ret)
+               goto err;
 
        /* Wait for the return of the report. The returned report
           gets put in session->report_return.  */
@@ -365,11 +370,13 @@ static int hidp_get_raw_report(struct hid_device *hid,
                        5*HZ);
                if (res == 0) {
                        /* timeout */
-                       goto err_eio;
+                       ret = -EIO;
+                       goto err;
                }
                if (res < 0) {
                        /* signal */
-                       goto err_restartsys;
+                       ret = -ERESTARTSYS;
+                       goto err;
                }
        }
 
@@ -390,14 +397,10 @@ static int hidp_get_raw_report(struct hid_device *hid,
 
        return len;
 
-err_restartsys:
-       clear_bit(HIDP_WAITING_FOR_RETURN, &session->flags);
-       mutex_unlock(&session->report_mutex);
-       return -ERESTARTSYS;
-err_eio:
+err:
        clear_bit(HIDP_WAITING_FOR_RETURN, &session->flags);
        mutex_unlock(&session->report_mutex);
-       return -EIO;
+       return ret;
 }
 
 static int hidp_output_raw_report(struct hid_device *hid, unsigned char *data, size_t count,
@@ -422,11 +425,10 @@ static int hidp_output_raw_report(struct hid_device *hid, unsigned char *data, s
 
        /* Set up our wait, and send the report request to the device. */
        set_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags);
-       if (hidp_send_ctrl_message(hid->driver_data, report_type,
-                       data, count)) {
-               ret = -ENOMEM;
+       ret = hidp_send_ctrl_message(hid->driver_data, report_type, data,
+                                                                       count);
+       if (ret)
                goto err;
-       }
 
        /* Wait for the ACK from the device. */
        while (test_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags)) {
@@ -739,6 +741,10 @@ static int hidp_session(void *arg)
        remove_wait_queue(sk_sleep(intr_sk), &intr_wait);
        remove_wait_queue(sk_sleep(ctrl_sk), &ctrl_wait);
 
+       clear_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags);
+       clear_bit(HIDP_WAITING_FOR_RETURN, &session->flags);
+       wake_up_interruptible(&session->report_queue);
+
        down_write(&hidp_session_sem);
 
        hidp_del_timer(session);