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>

1 files changed, 20 insertions, 14 deletions

diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index 075a3e920caf..d7bae2be83b2 100644
--- 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);