* [PATCH] bluetooth: Remove unnecessary smp_mb__after_atomic() barriers
@ 2018-11-27 11:22 Andrea Parri
2018-12-18 23:49 ` Marcel Holtmann
0 siblings, 1 reply; 2+ messages in thread
From: Andrea Parri @ 2018-11-27 11:22 UTC (permalink / raw)
To: Marcel Holtmann, Johan Hedberg
Cc: linux-bluetooth, linux-kernel, Andrea Parri
The barriers are redundant because atomic_test_and_clear_bit() already
provides the required full ordering for the cases in question (that is,
when the bit is cleared).
Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
---
drivers/bluetooth/btusb.c | 8 ++------
drivers/bluetooth/hci_intel.c | 16 ++++------------
2 files changed, 6 insertions(+), 18 deletions(-)
diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 7439a7eb50acb..885e17a1a9a57 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -1935,10 +1935,8 @@ static void btusb_intel_bootup(struct btusb_data *data, const void *ptr,
if (len != sizeof(*evt))
return;
- if (test_and_clear_bit(BTUSB_BOOTING, &data->flags)) {
- smp_mb__after_atomic();
+ if (test_and_clear_bit(BTUSB_BOOTING, &data->flags))
wake_up_bit(&data->flags, BTUSB_BOOTING);
- }
}
static void btusb_intel_secure_send_result(struct btusb_data *data,
@@ -1953,10 +1951,8 @@ static void btusb_intel_secure_send_result(struct btusb_data *data,
set_bit(BTUSB_FIRMWARE_FAILED, &data->flags);
if (test_and_clear_bit(BTUSB_DOWNLOADING, &data->flags) &&
- test_bit(BTUSB_FIRMWARE_LOADED, &data->flags)) {
- smp_mb__after_atomic();
+ test_bit(BTUSB_FIRMWARE_LOADED, &data->flags))
wake_up_bit(&data->flags, BTUSB_DOWNLOADING);
- }
}
static int btusb_recv_event_intel(struct hci_dev *hdev, struct sk_buff *skb)
diff --git a/drivers/bluetooth/hci_intel.c b/drivers/bluetooth/hci_intel.c
index 46ace321bf60e..8caa1a6619cea 100644
--- a/drivers/bluetooth/hci_intel.c
+++ b/drivers/bluetooth/hci_intel.c
@@ -909,10 +909,8 @@ static int intel_recv_event(struct hci_dev *hdev, struct sk_buff *skb)
set_bit(STATE_FIRMWARE_FAILED, &intel->flags);
if (test_and_clear_bit(STATE_DOWNLOADING, &intel->flags) &&
- test_bit(STATE_FIRMWARE_LOADED, &intel->flags)) {
- smp_mb__after_atomic();
+ test_bit(STATE_FIRMWARE_LOADED, &intel->flags))
wake_up_bit(&intel->flags, STATE_DOWNLOADING);
- }
/* When switching to the operational firmware the device
* sends a vendor specific event indicating that the bootup
@@ -920,10 +918,8 @@ static int intel_recv_event(struct hci_dev *hdev, struct sk_buff *skb)
*/
} else if (skb->len == 9 && hdr->evt == 0xff && hdr->plen == 0x07 &&
skb->data[2] == 0x02) {
- if (test_and_clear_bit(STATE_BOOTING, &intel->flags)) {
- smp_mb__after_atomic();
+ if (test_and_clear_bit(STATE_BOOTING, &intel->flags))
wake_up_bit(&intel->flags, STATE_BOOTING);
- }
}
recv:
return hci_recv_frame(hdev, skb);
@@ -960,17 +956,13 @@ static int intel_recv_lpm(struct hci_dev *hdev, struct sk_buff *skb)
break;
case LPM_OP_SUSPEND_ACK:
set_bit(STATE_SUSPENDED, &intel->flags);
- if (test_and_clear_bit(STATE_LPM_TRANSACTION, &intel->flags)) {
- smp_mb__after_atomic();
+ if (test_and_clear_bit(STATE_LPM_TRANSACTION, &intel->flags))
wake_up_bit(&intel->flags, STATE_LPM_TRANSACTION);
- }
break;
case LPM_OP_RESUME_ACK:
clear_bit(STATE_SUSPENDED, &intel->flags);
- if (test_and_clear_bit(STATE_LPM_TRANSACTION, &intel->flags)) {
- smp_mb__after_atomic();
+ if (test_and_clear_bit(STATE_LPM_TRANSACTION, &intel->flags))
wake_up_bit(&intel->flags, STATE_LPM_TRANSACTION);
- }
break;
default:
bt_dev_err(hdev, "Unknown LPM opcode (%02x)", lpm->opcode);
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] bluetooth: Remove unnecessary smp_mb__after_atomic() barriers
2018-11-27 11:22 [PATCH] bluetooth: Remove unnecessary smp_mb__after_atomic() barriers Andrea Parri
@ 2018-12-18 23:49 ` Marcel Holtmann
0 siblings, 0 replies; 2+ messages in thread
From: Marcel Holtmann @ 2018-12-18 23:49 UTC (permalink / raw)
To: Andrea Parri; +Cc: Johan Hedberg, linux-bluetooth, linux-kernel
Hi Andrea,
> The barriers are redundant because atomic_test_and_clear_bit() already
> provides the required full ordering for the cases in question (that is,
> when the bit is cleared).
>
> Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
> ---
> drivers/bluetooth/btusb.c | 8 ++------
> drivers/bluetooth/hci_intel.c | 16 ++++------------
> 2 files changed, 6 insertions(+), 18 deletions(-)
patch has been applied to bluetooth-next tree.
Regards
Marcel
^ permalink raw reply [flat|nested] 2+ messages in thread
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