* [PATCH 1/2] Bluetooth: btusb: Fix race when waiting for BTUSB_DOWNLOADING
@ 2015-01-30 8:58 Johan Hedberg
2015-01-30 8:58 ` [PATCH 2/2] Bluetooth: btusb: Use wait_on_bit_timeout() for BTUSB_BOOTING Johan Hedberg
2015-01-30 10:07 ` [PATCH 1/2] Bluetooth: btusb: Fix race when waiting for BTUSB_DOWNLOADING Marcel Holtmann
0 siblings, 2 replies; 4+ messages in thread
From: Johan Hedberg @ 2015-01-30 8:58 UTC (permalink / raw)
To: linux-bluetooth
From: Johan Hedberg <johan.hedberg@intel.com>
The test for BTUSB_DOWNLOADING must be after adding to the wait queue
and setting the TASK_INTERRUPTIBLE state. Otherwise the flag may get
cleared after we test for it and we end up getting a timeout since
schedule_timeout() waits for the full duration. This patch uses a
wait_on_bit_timeout() + wake_up_bit(). To perform the task both
race-free as well as in a much simpler way.
Since there's no global wait_on_bit_timeout() helper yet (even though
all the building blocks for it are in place) this patch creates a
temporary local btusb copy of it until the global one has made it to
upstream trees.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
---
drivers/bluetooth/btusb.c | 67 ++++++++++++++++++++++++-----------------------
1 file changed, 34 insertions(+), 33 deletions(-)
diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 3aa4b3c776b2..808568d2722f 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -334,6 +334,16 @@ struct btusb_data {
int (*recv_bulk)(struct btusb_data *data, void *buffer, int count);
};
+static int btusb_wait_on_bit_timeout(void *word, int bit, unsigned long timeout,
+ unsigned mode)
+{
+ might_sleep();
+ if (!test_bit(bit, word))
+ return 0;
+ return out_of_line_wait_on_bit_timeout(word, bit, bit_wait_timeout,
+ mode, timeout);
+}
+
static inline void btusb_free_frags(struct btusb_data *data)
{
unsigned long flags;
@@ -1800,8 +1810,10 @@ static int btusb_recv_event_intel(struct hci_dev *hdev, struct sk_buff *skb)
if (test_and_clear_bit(BTUSB_DOWNLOADING,
&data->flags) &&
- test_bit(BTUSB_FIRMWARE_LOADED, &data->flags))
- wake_up_interruptible(&hdev->req_wait_q);
+ test_bit(BTUSB_FIRMWARE_LOADED, &data->flags)) {
+ smp_mb__after_atomic();
+ wake_up_bit(&data->flags, BTUSB_DOWNLOADING);
+ }
}
/* When switching to the operational firmware the device
@@ -2165,43 +2177,32 @@ static int btusb_setup_intel_new(struct hci_dev *hdev)
set_bit(BTUSB_FIRMWARE_LOADED, &data->flags);
+ BT_INFO("%s: Waiting for firmware download to complete", hdev->name);
+
/* Before switching the device into operational mode and with that
* booting the loaded firmware, wait for the bootloader notification
* that all fragments have been successfully received.
*
- * When the event processing receives the notification, then this
- * flag will be cleared. So just in case that happens really quickly,
- * check it first before adding the wait queue.
+ * When the event processing receives the notification, then the
+ * BTUSB_DOWNLOADING flag will be cleared.
+ *
+ * The firmware loading should not take longer than 5 seconds
+ * and thus just timeout if that happens and fail the setup
+ * of this device.
*/
- if (test_bit(BTUSB_DOWNLOADING, &data->flags)) {
- DECLARE_WAITQUEUE(wait, current);
- signed long timeout;
-
- BT_INFO("%s: Waiting for firmware download to complete",
- hdev->name);
-
- add_wait_queue(&hdev->req_wait_q, &wait);
- set_current_state(TASK_INTERRUPTIBLE);
-
- /* The firmware loading should not take longer than 5 seconds
- * and thus just timeout if that happens and fail the setup
- * of this device.
- */
- timeout = schedule_timeout(msecs_to_jiffies(5000));
-
- remove_wait_queue(&hdev->req_wait_q, &wait);
-
- if (signal_pending(current)) {
- BT_ERR("%s: Firmware loading interrupted", hdev->name);
- err = -EINTR;
- goto done;
- }
+ err = btusb_wait_on_bit_timeout(&data->flags, BTUSB_DOWNLOADING,
+ msecs_to_jiffies(5000),
+ TASK_INTERRUPTIBLE);
+ if (err == 1) {
+ BT_ERR("%s: Firmware loading interrupted", hdev->name);
+ err = -EINTR;
+ goto done;
+ }
- if (!timeout) {
- BT_ERR("%s: Firmware loading timeout", hdev->name);
- err = -ETIMEDOUT;
- goto done;
- }
+ if (err) {
+ BT_ERR("%s: Firmware loading timeout", hdev->name);
+ err = -ETIMEDOUT;
+ goto done;
}
if (test_bit(BTUSB_FIRMWARE_FAILED, &data->flags)) {
--
2.1.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 2/2] Bluetooth: btusb: Use wait_on_bit_timeout() for BTUSB_BOOTING
2015-01-30 8:58 [PATCH 1/2] Bluetooth: btusb: Fix race when waiting for BTUSB_DOWNLOADING Johan Hedberg
@ 2015-01-30 8:58 ` Johan Hedberg
2015-01-30 10:07 ` Marcel Holtmann
2015-01-30 10:07 ` [PATCH 1/2] Bluetooth: btusb: Fix race when waiting for BTUSB_DOWNLOADING Marcel Holtmann
1 sibling, 1 reply; 4+ messages in thread
From: Johan Hedberg @ 2015-01-30 8:58 UTC (permalink / raw)
To: linux-bluetooth
From: Johan Hedberg <johan.hedberg@intel.com>
The wait_on_bit_timeout() is a simpler and race-free way of waiting for
a bit to be cleared than the current code in btusb.c. This patch updates
the code to use the helper function (its btusb copy - to be later
updated to use a global one).
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
---
drivers/bluetooth/btusb.c | 44 +++++++++++++++++++-------------------------
1 file changed, 19 insertions(+), 25 deletions(-)
diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 808568d2722f..f67bf761144e 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -1822,8 +1822,10 @@ static int btusb_recv_event_intel(struct hci_dev *hdev, struct sk_buff *skb)
*/
if (skb->len == 9 && hdr->evt == 0xff && hdr->plen == 0x07 &&
skb->data[2] == 0x02) {
- if (test_and_clear_bit(BTUSB_BOOTING, &data->flags))
- wake_up_interruptible(&hdev->req_wait_q);
+ if (test_and_clear_bit(BTUSB_BOOTING, &data->flags)) {
+ smp_mb__after_atomic();
+ wake_up_bit(&data->flags, BTUSB_BOOTING);
+ }
}
}
@@ -2236,33 +2238,25 @@ done:
/* The bootloader will not indicate when the device is ready. This
* is done by the operational firmware sending bootup notification.
+ *
+ * Booting into operational firmware should not take longer than
+ * 1 second. However if that happens, then just fail the setup
+ * since something went wrong.
*/
- if (test_bit(BTUSB_BOOTING, &data->flags)) {
- DECLARE_WAITQUEUE(wait, current);
- signed long timeout;
-
- BT_INFO("%s: Waiting for device to boot", hdev->name);
-
- add_wait_queue(&hdev->req_wait_q, &wait);
- set_current_state(TASK_INTERRUPTIBLE);
-
- /* Booting into operational firmware should not take
- * longer than 1 second. However if that happens, then
- * just fail the setup since something went wrong.
- */
- timeout = schedule_timeout(msecs_to_jiffies(1000));
+ BT_INFO("%s: Waiting for device to boot", hdev->name);
- remove_wait_queue(&hdev->req_wait_q, &wait);
+ err = btusb_wait_on_bit_timeout(&data->flags, BTUSB_BOOTING,
+ msecs_to_jiffies(1000),
+ TASK_INTERRUPTIBLE);
- if (signal_pending(current)) {
- BT_ERR("%s: Device boot interrupted", hdev->name);
- return -EINTR;
- }
+ if (err == 1) {
+ BT_ERR("%s: Device boot interrupted", hdev->name);
+ return -EINTR;
+ }
- if (!timeout) {
- BT_ERR("%s: Device boot timeout", hdev->name);
- return -ETIMEDOUT;
- }
+ if (err) {
+ BT_ERR("%s: Device boot timeout", hdev->name);
+ return -ETIMEDOUT;
}
rettime = ktime_get();
--
2.1.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH 2/2] Bluetooth: btusb: Use wait_on_bit_timeout() for BTUSB_BOOTING
2015-01-30 8:58 ` [PATCH 2/2] Bluetooth: btusb: Use wait_on_bit_timeout() for BTUSB_BOOTING Johan Hedberg
@ 2015-01-30 10:07 ` Marcel Holtmann
0 siblings, 0 replies; 4+ messages in thread
From: Marcel Holtmann @ 2015-01-30 10:07 UTC (permalink / raw)
To: Johan Hedberg; +Cc: linux-bluetooth
Hi Johan,
> The wait_on_bit_timeout() is a simpler and race-free way of waiting for
> a bit to be cleared than the current code in btusb.c. This patch updates
> the code to use the helper function (its btusb copy - to be later
> updated to use a global one).
>
> Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
> ---
> drivers/bluetooth/btusb.c | 44 +++++++++++++++++++-------------------------
> 1 file changed, 19 insertions(+), 25 deletions(-)
patch has been applied to bluetooth-next tree.
Regards
Marcel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] Bluetooth: btusb: Fix race when waiting for BTUSB_DOWNLOADING
2015-01-30 8:58 [PATCH 1/2] Bluetooth: btusb: Fix race when waiting for BTUSB_DOWNLOADING Johan Hedberg
2015-01-30 8:58 ` [PATCH 2/2] Bluetooth: btusb: Use wait_on_bit_timeout() for BTUSB_BOOTING Johan Hedberg
@ 2015-01-30 10:07 ` Marcel Holtmann
1 sibling, 0 replies; 4+ messages in thread
From: Marcel Holtmann @ 2015-01-30 10:07 UTC (permalink / raw)
To: Johan Hedberg; +Cc: linux-bluetooth
Hi Johan,
> The test for BTUSB_DOWNLOADING must be after adding to the wait queue
> and setting the TASK_INTERRUPTIBLE state. Otherwise the flag may get
> cleared after we test for it and we end up getting a timeout since
> schedule_timeout() waits for the full duration. This patch uses a
> wait_on_bit_timeout() + wake_up_bit(). To perform the task both
> race-free as well as in a much simpler way.
>
> Since there's no global wait_on_bit_timeout() helper yet (even though
> all the building blocks for it are in place) this patch creates a
> temporary local btusb copy of it until the global one has made it to
> upstream trees.
>
> Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
> ---
> drivers/bluetooth/btusb.c | 67 ++++++++++++++++++++++++-----------------------
> 1 file changed, 34 insertions(+), 33 deletions(-)
patch has been applied to bluetooth-next tree.
Regards
Marcel
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2015-01-30 10:07 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-01-30 8:58 [PATCH 1/2] Bluetooth: btusb: Fix race when waiting for BTUSB_DOWNLOADING Johan Hedberg
2015-01-30 8:58 ` [PATCH 2/2] Bluetooth: btusb: Use wait_on_bit_timeout() for BTUSB_BOOTING Johan Hedberg
2015-01-30 10:07 ` Marcel Holtmann
2015-01-30 10:07 ` [PATCH 1/2] Bluetooth: btusb: Fix race when waiting for BTUSB_DOWNLOADING Marcel Holtmann
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