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| author | Frederic Danis <frederic.danis@linux.intel.com> | 2015-09-23 18:18:10 +0200 |
|---|---|---|
| committer | Marcel Holtmann <marcel@holtmann.org> | 2015-09-24 16:25:44 +0200 |
| commit | 7649faff1cfe4f76dabf78cd53d659d39f65b3c1 (patch) | |
| tree | 6a7c94c698155ec951247af76fce02b9b98c629e | |
| parent | b7a622a249736b36c0bf4c3f986ed431281d5e98 (diff) | |
| download | linux-7649faff1cfe4f76dabf78cd53d659d39f65b3c1.tar.gz linux-7649faff1cfe4f76dabf78cd53d659d39f65b3c1.tar.bz2 linux-7649faff1cfe4f76dabf78cd53d659d39f65b3c1.zip | |
Bluetooth: Remove useless rx_lock spinlock
rx_lock spinlock is only used in hci_uart_tty_receive() which is the
receive_buf ldisc callback.
hci_uart_tty_receive() is protected from re-entrance by its only
caller (flush_to_ldisc() in drivers/tty/tty_buffer.c) which held a
mutex (buf->lock) for this section.
This lock allows "safe use of the line discipline's receive_buf()
method by excluding the buffer work and any pending flush from using
the flip buffer." (comments from tty_buffer_lock_exclusive() in
drivers/tty/tty_buffer.c)
So, no need to double protect this resource with rx_lock.
Signed-off-by: Frederic Danis <frederic.danis@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
| -rw-r--r-- | drivers/bluetooth/hci_ldisc.c | 8 | ||||
| -rw-r--r-- | drivers/bluetooth/hci_uart.h | 1 |
2 files changed, 3 insertions, 6 deletions
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c index 0d5a05a7c1fd..ad66c690d272 100644 --- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -470,8 +470,6 @@ static int hci_uart_tty_open(struct tty_struct *tty) INIT_WORK(&hu->init_ready, hci_uart_init_work); INIT_WORK(&hu->write_work, hci_uart_write_work); - spin_lock_init(&hu->rx_lock); - /* Flush any pending characters in the driver and line discipline. */ /* FIXME: why is this needed. Note don't use ldisc_ref here as the @@ -569,14 +567,14 @@ static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data, if (!test_bit(HCI_UART_PROTO_SET, &hu->flags)) return; - spin_lock(&hu->rx_lock); + /* It does not need a lock here as it is already protected by a mutex in + * tty caller + */ hu->proto->recv(hu, data, count); if (hu->hdev) hu->hdev->stat.byte_rx += count; - spin_unlock(&hu->rx_lock); - tty_unthrottle(tty); } diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h index 495b9ef52bb0..2f7bb35a890e 100644 --- a/drivers/bluetooth/hci_uart.h +++ b/drivers/bluetooth/hci_uart.h @@ -85,7 +85,6 @@ struct hci_uart { struct sk_buff *tx_skb; unsigned long tx_state; - spinlock_t rx_lock; unsigned int init_speed; unsigned int oper_speed; |