[PATCH] staging: gpib: Replace semaphore with completion for one-time signaling

From: eisantosh95
Date: Thu Dec 12 2024 - 11:47:45 EST


From: Santosh Mahto <eisantosh95@xxxxxxxxx>

Replaced 'down_interruptible()' and 'up()' calls
with 'wait_for_completion_interruptible()' and
'complete()' respectively. The completion API
simplifies the code and adheres to kernel best
practices for synchronization primitive

Signed-off-by: Santosh Mahto <eisantosh95@xxxxxxxxx>
---
drivers/staging/gpib/ni_usb/ni_usb_gpib.c | 16 ++++++++--------
drivers/staging/gpib/ni_usb/ni_usb_gpib.h | 2 +-
2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/gpib/ni_usb/ni_usb_gpib.c b/drivers/staging/gpib/ni_usb/ni_usb_gpib.c
index b7b6fb1be379..70b8b305e13b 100644
--- a/drivers/staging/gpib/ni_usb/ni_usb_gpib.c
+++ b/drivers/staging/gpib/ni_usb/ni_usb_gpib.c
@@ -85,7 +85,7 @@ static void ni_usb_bulk_complete(struct urb *urb)

// printk("debug: %s: status=0x%x, error_count=%i, actual_length=%i\n", __func__,
// urb->status, urb->error_count, urb->actual_length);
- up(&context->complete);
+ complete(&context->complete);
}

static void ni_usb_timeout_handler(struct timer_list *t)
@@ -94,7 +94,7 @@ static void ni_usb_timeout_handler(struct timer_list *t)
struct ni_usb_urb_ctx *context = &ni_priv->context;

context->timed_out = 1;
- up(&context->complete);
+ complete(&context->complete);
};

// I'm using nonblocking loosely here, it only means -EAGAIN can be returned in certain cases
@@ -124,7 +124,7 @@ static int ni_usb_nonblocking_send_bulk_msg(struct ni_usb_priv *ni_priv, void *d
}
usb_dev = interface_to_usbdev(ni_priv->bus_interface);
out_pipe = usb_sndbulkpipe(usb_dev, ni_priv->bulk_out_endpoint);
- sema_init(&context->complete, 0);
+ init_completion(&context->complete);
context->timed_out = 0;
usb_fill_bulk_urb(ni_priv->bulk_urb, usb_dev, out_pipe, data, data_length,
&ni_usb_bulk_complete, context);
@@ -143,7 +143,7 @@ static int ni_usb_nonblocking_send_bulk_msg(struct ni_usb_priv *ni_priv, void *d
return retval;
}
mutex_unlock(&ni_priv->bulk_transfer_lock);
- down(&context->complete); // wait for ni_usb_bulk_complete
+ wait_for_completion(&context->complete); // wait for ni_usb_bulk_complete
if (context->timed_out) {
usb_kill_urb(ni_priv->bulk_urb);
dev_err(&usb_dev->dev, "%s: killed urb due to timeout\n", __func__);
@@ -210,7 +210,7 @@ static int ni_usb_nonblocking_receive_bulk_msg(struct ni_usb_priv *ni_priv,
}
usb_dev = interface_to_usbdev(ni_priv->bus_interface);
in_pipe = usb_rcvbulkpipe(usb_dev, ni_priv->bulk_in_endpoint);
- sema_init(&context->complete, 0);
+ init_completion(&context->complete);
context->timed_out = 0;
usb_fill_bulk_urb(ni_priv->bulk_urb, usb_dev, in_pipe, data, data_length,
&ni_usb_bulk_complete, context);
@@ -231,7 +231,7 @@ static int ni_usb_nonblocking_receive_bulk_msg(struct ni_usb_priv *ni_priv,
}
mutex_unlock(&ni_priv->bulk_transfer_lock);
if (interruptible) {
- if (down_interruptible(&context->complete)) {
+ if (wait_for_completion_interruptible(&context->complete)) {
/* If we got interrupted by a signal while
* waiting for the usb gpib to respond, we
* should send a stop command so it will
@@ -243,10 +243,10 @@ static int ni_usb_nonblocking_receive_bulk_msg(struct ni_usb_priv *ni_priv,
/* now do an uninterruptible wait, it shouldn't take long
* for the board to respond now.
*/
- down(&context->complete);
+ wait_for_completion(&context->complete);
}
} else {
- down(&context->complete);
+ wait_for_completion(&context->complete);
}
if (context->timed_out) {
usb_kill_urb(ni_priv->bulk_urb);
diff --git a/drivers/staging/gpib/ni_usb/ni_usb_gpib.h b/drivers/staging/gpib/ni_usb/ni_usb_gpib.h
index 9b21dfa0f3f6..4b297db09a9b 100644
--- a/drivers/staging/gpib/ni_usb/ni_usb_gpib.h
+++ b/drivers/staging/gpib/ni_usb/ni_usb_gpib.h
@@ -56,7 +56,7 @@ enum hs_plus_endpoint_addresses {
};

struct ni_usb_urb_ctx {
- struct semaphore complete;
+ struct completion complete;
unsigned timed_out : 1;
};

--
2.25.1