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USB: cdc-wdm: support back-to-back USB_CDC_NOTIFY_RESPONSE_AVAILABLE notifications

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Some MBIM devices send back-to-back USB_CDC_NOTIFY_RESPONSE_AVAILABLE notifications
when sending a message over multiple fragments or when there are unsolicited
messages available.

Count up the number of USB_CDC_NOTIFY_RESPONSE_AVAILABLE notifications received
and decrement the count and submit the urb for the next response each time userspace
completes a read the response.

Signed-off-by: Greg Suarez <gsuarez@smithmicro.com>
Acked-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Greg Suarez 2013-10-29 10:29:10 -07:00 committed by Greg Kroah-Hartman
parent 32e24930fb
commit 73e06865ea
1 changed files with 34 additions and 4 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

38
drivers/usb/class/cdc-wdm.c
View file

@ -101,6 +101,7 @@ struct wdm_device {
struct work_struct rxwork;
int werr;
int rerr;
int resp_count;
struct list_head device_list;
int (*manage_power)(struct usb_interface *, int);
@ -262,9 +263,9 @@ static void wdm_int_callback(struct urb *urb)
}
spin_lock(&desc->iuspin);
clear_bit(WDM_READ, &desc->flags);
responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
if (!responding && !test_bit(WDM_DISCONNECTING, &desc->flags)
if (!desc->resp_count++ && !responding
&& !test_bit(WDM_DISCONNECTING, &desc->flags)
&& !test_bit(WDM_SUSPENDING, &desc->flags)) {
rv = usb_submit_urb(desc->response, GFP_ATOMIC);
dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
@ -521,10 +522,36 @@ static ssize_t wdm_read
desc->length -= cntr;
/* in case we had outstanding data */
if (!desc->length)
if (!desc->length) {
clear_bit(WDM_READ, &desc->flags);
spin_unlock_irq(&desc->iuspin);
if (--desc->resp_count) {
set_bit(WDM_RESPONDING, &desc->flags);
spin_unlock_irq(&desc->iuspin);
rv = usb_submit_urb(desc->response, GFP_KERNEL);
if (rv) {
dev_err(&desc->intf->dev,
"%s: usb_submit_urb failed with result %d\n",
__func__, rv);
spin_lock_irq(&desc->iuspin);
clear_bit(WDM_RESPONDING, &desc->flags);
spin_unlock_irq(&desc->iuspin);
if (rv == -ENOMEM) {
rv = schedule_work(&desc->rxwork);
if (rv)
dev_err(&desc->intf->dev, "Cannot schedule work\n");
} else {
spin_lock_irq(&desc->iuspin);
desc->resp_count = 0;
spin_unlock_irq(&desc->iuspin);
}
}
} else
spin_unlock_irq(&desc->iuspin);
} else
spin_unlock_irq(&desc->iuspin);
rv = cntr;
@ -635,6 +662,9 @@ static int wdm_release(struct inode *inode, struct file *file)
if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
kill_urbs(desc);
spin_lock_irq(&desc->iuspin);
desc->resp_count = 0;
spin_unlock_irq(&desc->iuspin);
desc->manage_power(desc->intf, 0);
} else {
/* must avoid dev_printk here as desc->intf is invalid */