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Subject[patch V2 22/36] net: usb: kaweth: Remove last user of kaweth_control()
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

kaweth_async_set_rx_mode() invokes kaweth_contol() and has two callers:

- kaweth_open() which is invoked from preemptible context
.
- kaweth_start_xmit() which holds a spinlock and has bottom halfs disabled.

If called from kaweth_start_xmit() kaweth_async_set_rx_mode() obviously
cannot block, which means it can't call kaweth_control(). This is detected
with an in_interrupt() check.

Replace the in_interrupt() check in kaweth_async_set_rx_mode() with an
argument which is set true by the caller if the context is safe to sleep,
otherwise false.

Now kaweth_control() is only called from preemptible context which means
there is no need for GFP_ATOMIC allocations anymore. Replace it with
usb_control_msg(). Cleanup the code a bit while at it.

Finally remove kaweth_control() since the last user is gone.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


---
drivers/net/usb/kaweth.c | 168 ++++-------------------------------------------
1 file changed, 17 insertions(+), 151 deletions(-)

--- a/drivers/net/usb/kaweth.c
+++ b/drivers/net/usb/kaweth.c
@@ -103,10 +103,6 @@ static int kaweth_probe(
const struct usb_device_id *id /* from id_table */
);
static void kaweth_disconnect(struct usb_interface *intf);
-static int kaweth_internal_control_msg(struct usb_device *usb_dev,
- unsigned int pipe,
- struct usb_ctrlrequest *cmd, void *data,
- int len, int timeout);
static int kaweth_suspend(struct usb_interface *intf, pm_message_t message);
static int kaweth_resume(struct usb_interface *intf);

@@ -236,48 +232,6 @@ struct kaweth_device
};

/****************************************************************
- * kaweth_control
- ****************************************************************/
-static int kaweth_control(struct kaweth_device *kaweth,
- unsigned int pipe,
- __u8 request,
- __u8 requesttype,
- __u16 value,
- __u16 index,
- void *data,
- __u16 size,
- int timeout)
-{
- struct usb_ctrlrequest *dr;
- int retval;
-
- if(in_interrupt()) {
- netdev_dbg(kaweth->net, "in_interrupt()\n");
- return -EBUSY;
- }
-
- dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
- if (!dr)
- return -ENOMEM;
-
- dr->bRequestType = requesttype;
- dr->bRequest = request;
- dr->wValue = cpu_to_le16(value);
- dr->wIndex = cpu_to_le16(index);
- dr->wLength = cpu_to_le16(size);
-
- retval = kaweth_internal_control_msg(kaweth->dev,
- pipe,
- dr,
- data,
- size,
- timeout);
-
- kfree(dr);
- return retval;
-}
-
-/****************************************************************
* kaweth_read_configuration
****************************************************************/
static int kaweth_read_configuration(struct kaweth_device *kaweth)
@@ -531,7 +485,8 @@ static int kaweth_resubmit_rx_urb(struct
return result;
}

-static void kaweth_async_set_rx_mode(struct kaweth_device *kaweth);
+static void kaweth_async_set_rx_mode(struct kaweth_device *kaweth,
+ bool may_sleep);

/****************************************************************
* kaweth_usb_receive
@@ -661,7 +616,7 @@ static int kaweth_open(struct net_device

netif_start_queue(net);

- kaweth_async_set_rx_mode(kaweth);
+ kaweth_async_set_rx_mode(kaweth, true);
return 0;

err_out:
@@ -749,7 +704,7 @@ static netdev_tx_t kaweth_start_xmit(str

spin_lock_irq(&kaweth->device_lock);

- kaweth_async_set_rx_mode(kaweth);
+ kaweth_async_set_rx_mode(kaweth, false);
netif_stop_queue(net);
if (IS_BLOCKED(kaweth->status)) {
goto skip;
@@ -826,36 +781,31 @@ static void kaweth_set_rx_mode(struct ne
/****************************************************************
* kaweth_async_set_rx_mode
****************************************************************/
-static void kaweth_async_set_rx_mode(struct kaweth_device *kaweth)
+static void kaweth_async_set_rx_mode(struct kaweth_device *kaweth,
+ bool may_sleep)
{
- int result;
+ int ret;
__u16 packet_filter_bitmap = kaweth->packet_filter_bitmap;

kaweth->packet_filter_bitmap = 0;
if (packet_filter_bitmap == 0)
return;

- if (in_interrupt())
+ if (!may_sleep)
return;

- result = kaweth_control(kaweth,
- usb_sndctrlpipe(kaweth->dev, 0),
- KAWETH_COMMAND_SET_PACKET_FILTER,
- USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE,
- packet_filter_bitmap,
- 0,
- (void *)&kaweth->scratch,
- 0,
- KAWETH_CONTROL_TIMEOUT);
-
- if(result < 0) {
+ ret = usb_control_msg(kaweth->dev, usb_sndctrlpipe(kaweth->dev, 0),
+ KAWETH_COMMAND_SET_PACKET_FILTER,
+ USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE,
+ packet_filter_bitmap, 0,
+ &kaweth->scratch, 0,
+ KAWETH_CONTROL_TIMEOUT);
+ if (ret < 0)
dev_err(&kaweth->intf->dev, "Failed to set Rx mode: %d\n",
- result);
- }
- else {
+ ret);
+ else
netdev_dbg(kaweth->net, "Set Rx mode to %d\n",
packet_filter_bitmap);
- }
}

/****************************************************************
@@ -1163,88 +1113,4 @@ static void kaweth_disconnect(struct usb
}


-// FIXME this completion stuff is a modified clone of
-// an OLD version of some stuff in usb.c ...
-struct usb_api_data {
- wait_queue_head_t wqh;
- int done;
-};
-
-/*-------------------------------------------------------------------*
- * completion handler for compatibility wrappers (sync control/bulk) *
- *-------------------------------------------------------------------*/
-static void usb_api_blocking_completion(struct urb *urb)
-{
- struct usb_api_data *awd = (struct usb_api_data *)urb->context;
-
- awd->done=1;
- wake_up(&awd->wqh);
-}
-
-/*-------------------------------------------------------------------*
- * COMPATIBILITY STUFF *
- *-------------------------------------------------------------------*/
-
-// Starts urb and waits for completion or timeout
-static int usb_start_wait_urb(struct urb *urb, int timeout, int* actual_length)
-{
- struct usb_api_data awd;
- int status;
-
- init_waitqueue_head(&awd.wqh);
- awd.done = 0;
-
- urb->context = &awd;
- status = usb_submit_urb(urb, GFP_ATOMIC);
- if (status) {
- // something went wrong
- usb_free_urb(urb);
- return status;
- }
-
- if (!wait_event_timeout(awd.wqh, awd.done, timeout)) {
- // timeout
- dev_warn(&urb->dev->dev, "usb_control/bulk_msg: timeout\n");
- usb_kill_urb(urb); // remove urb safely
- status = -ETIMEDOUT;
- }
- else {
- status = urb->status;
- }
-
- if (actual_length) {
- *actual_length = urb->actual_length;
- }
-
- usb_free_urb(urb);
- return status;
-}
-
-/*-------------------------------------------------------------------*/
-// returns status (negative) or length (positive)
-static int kaweth_internal_control_msg(struct usb_device *usb_dev,
- unsigned int pipe,
- struct usb_ctrlrequest *cmd, void *data,
- int len, int timeout)
-{
- struct urb *urb;
- int retv;
- int length = 0; /* shut up GCC */
-
- urb = usb_alloc_urb(0, GFP_ATOMIC);
- if (!urb)
- return -ENOMEM;
-
- usb_fill_control_urb(urb, usb_dev, pipe, (unsigned char*)cmd, data,
- len, usb_api_blocking_completion, NULL);
-
- retv = usb_start_wait_urb(urb, timeout, &length);
- if (retv < 0) {
- return retv;
- }
- else {
- return length;
- }
-}
-
module_usb_driver(kaweth_driver);

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