[PATCH 0/2] media: Use complete() instead complete_all()

[PATCH 0/2] media: Use complete() instead complete_all()

[Daniel Wagner]

From: Daniel Wagner <daniel.wagner@bmw-carit.de>

Hi,

Using complete_all() is not wrong per se but it suggest that there
might be more than one waiter. For -rt I am reviewing all
complete_all() users and would like to leave only the real ones in the
tree. The main problem for -rt about complete_all() is that it can be
uses inside IRQ context and that can lead to unbounded amount work
inside the interrupt handler. That is a no no for -rt.

cheers,
daniel

Daniel Wagner (2):
  [media] imon: use complete() instead of complete_all()
  [media] lirc_imon: use complete() instead complete_all()

 drivers/media/rc/imon.c                | 6 ++++--
 drivers/staging/media/lirc/lirc_imon.c | 6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

-- 
2.7.4

[PATCH 1/2] [media] imon: use complete() instead of complete_all()

[Daniel Wagner]

From: Daniel Wagner <daniel.wagner@bmw-carit.de>

There is only one waiter for the completion, therefore there is no need
to use complete_all(). Let's make that clear by using complete() instead
of complete_all().

While we are at it, we do a small optimization with the reinitialization
of the completion before we use it.

The usage pattern of the completion is:

waiter context                          waker context

send_packet()
  init_completion()
  usb_submit_urb()
  wait_for_completion_interruptible()

                                        usb_tx_callback()
                                          complete()

                                        imon_disonnect()
                                          complete()

Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
---
 drivers/media/rc/imon.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/media/rc/imon.c b/drivers/media/rc/imon.c
index 65f80b8..38cdfd6 100644
--- a/drivers/media/rc/imon.c
+++ b/drivers/media/rc/imon.c
@@ -611,7 +611,7 @@ static int send_packet(struct imon_context *ictx)
 		ictx->tx_urb->actual_length = 0;
 	}
 
-	init_completion(&ictx->tx.finished);
+	reinit_completion(&ictx->tx.finished);
 	ictx->tx.busy = true;
 	smp_rmb(); /* ensure later readers know we're busy */
 
@@ -2233,6 +2233,8 @@ static struct imon_context *imon_init_intf0(struct usb_interface *intf,
 	ictx->tx_urb = tx_urb;
 	ictx->rf_device = false;
 
+	init_completion(&ictx->tx.finished);
+
 	ictx->vendor  = le16_to_cpu(ictx->usbdev_intf0->descriptor.idVendor);
 	ictx->product = le16_to_cpu(ictx->usbdev_intf0->descriptor.idProduct);
 
@@ -2511,7 +2513,7 @@ static void imon_disconnect(struct usb_interface *interface)
 	/* Abort ongoing write */
 	if (ictx->tx.busy) {
 		usb_kill_urb(ictx->tx_urb);
-		complete_all(&ictx->tx.finished);
+		complete(&ictx->tx.finished);
 	}
 
 	if (ifnum == 0) {
-- 
2.7.4

[PATCH 2/2] [media] lirc_imon: use complete() instead complete_all()

[Daniel Wagner]

From: Daniel Wagner <daniel.wagner@bmw-carit.de>

There is only one waiter for the completion, therefore there
is no need to use complete_all(). Let's make that clear by
using complete() instead of complete_all().

While we are at it, we do a small optimization with the
reinitialization of the completion before we use it.

The usage pattern of the completion is:

waiter context                          waker context

send_packet()
  reinit_completion()
  usb_sumbit_urb()
  wait_for_completion_interruptible()

                                        usb_tx_callback()
                                          complete()

                                        imon_disconnect()
                                          complete()

Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
---
 drivers/staging/media/lirc/lirc_imon.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/media/lirc/lirc_imon.c b/drivers/staging/media/lirc/lirc_imon.c
index ff1926c..c449434 100644
--- a/drivers/staging/media/lirc/lirc_imon.c
+++ b/drivers/staging/media/lirc/lirc_imon.c
@@ -336,7 +336,7 @@ static int send_packet(struct imon_context *context)
 
 	context->tx_urb->actual_length = 0;
 
-	init_completion(&context->tx.finished);
+	reinit_completion(&context->tx.finished);
 	atomic_set(&context->tx.busy, 1);
 
 	retval = usb_submit_urb(context->tx_urb, GFP_KERNEL);
@@ -499,6 +499,8 @@ static int ir_open(void *data)
 	context->rx.initial_space = 1;
 	context->rx.prev_bit = 0;
 
+	init_completion(&context->tx.finished);
+
 	context->ir_isopen = 1;
 	dev_info(context->driver->dev, "IR port opened\n");
 
@@ -937,7 +939,7 @@ static void imon_disconnect(struct usb_interface *interface)
 	/* Abort ongoing write */
 	if (atomic_read(&context->tx.busy)) {
 		usb_kill_urb(context->tx_urb);
-		complete_all(&context->tx.finished);
+		complete(&context->tx.finished);
 	}
 
 	context->dev_present = 0;
-- 
2.7.4