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usb: cdc-wdm: Fix race between autosuspend and reading from the device

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While an available response is read the device must not
be autosuspended. This requires a flag dedicated to that
purpose.

Signed-off-by: Oliver Neukum <neukum@b1-systems.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Oliver Neukum 2010-02-27 20:54:59 +01:00 committed by Greg Kroah-Hartman
parent 860e41a71c
commit 922a5eadd5
1 changed files with 10 additions and 4 deletions
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14
drivers/usb/class/cdc-wdm.c
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@ -52,6 +52,7 @@ MODULE_DEVICE_TABLE (usb, wdm_ids);
#define WDM_READ 4
#define WDM_INT_STALL 5
#define WDM_POLL_RUNNING 6
#define WDM_RESPONDING 7
#define WDM_MAX 16
@ -115,21 +116,22 @@ static void wdm_in_callback(struct urb *urb)
int status = urb->status;
spin_lock(&desc->iuspin);
clear_bit(WDM_RESPONDING, &desc->flags);
if (status) {
switch (status) {
case -ENOENT:
dev_dbg(&desc->intf->dev,
"nonzero urb status received: -ENOENT");
break;
goto skip_error;
case -ECONNRESET:
dev_dbg(&desc->intf->dev,
"nonzero urb status received: -ECONNRESET");
break;
goto skip_error;
case -ESHUTDOWN:
dev_dbg(&desc->intf->dev,
"nonzero urb status received: -ESHUTDOWN");
break;
goto skip_error;
case -EPIPE:
dev_err(&desc->intf->dev,
"nonzero urb status received: -EPIPE\n");
@ -145,6 +147,7 @@ static void wdm_in_callback(struct urb *urb)
desc->reslength = urb->actual_length;
memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength);
desc->length += desc->reslength;
skip_error:
wake_up(&desc->wait);
set_bit(WDM_READ, &desc->flags);
@ -227,6 +230,7 @@ static void wdm_int_callback(struct urb *urb)
desc->response->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
spin_lock(&desc->iuspin);
clear_bit(WDM_READ, &desc->flags);
set_bit(WDM_RESPONDING, &desc->flags);
if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
rv = usb_submit_urb(desc->response, GFP_ATOMIC);
dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
@ -234,6 +238,7 @@ static void wdm_int_callback(struct urb *urb)
}
spin_unlock(&desc->iuspin);
if (rv < 0) {
clear_bit(WDM_RESPONDING, &desc->flags);
if (rv == -EPERM)
return;
if (rv == -ENOMEM) {
@ -795,7 +800,8 @@ static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
mutex_lock(&desc->lock);
#ifdef CONFIG_PM
if ((message.event & PM_EVENT_AUTO) &&
test_bit(WDM_IN_USE, &desc->flags)) {
(test_bit(WDM_IN_USE, &desc->flags)
|| test_bit(WDM_RESPONDING, &desc->flags))) {
rv = -EBUSY;
} else {
#endif