>From ff993b8cf68e7e9c40abe331873fc20ce89a3590 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oliver@xxxxxxxxxx>
Date: Tue, 9 Feb 2010 16:46:33 +0100
Subject: [PATCH 2/6] usb: cdc-wdm:Fix race between autosuspend and reading from the device
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@xxxxxxxxxxxxx>
---
drivers/usb/class/cdc-wdm.c | 14 ++++++++++----
1 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index e1d6b82..413541e 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -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
--
1.6.4.2
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