In the code path
__usb_hcd_giveback_urb()
-> wdm_in_callback()
-> service_outstanding_interrupt()
The function service_outstanding_interrupt() will unconditionally enable
interrupts during unlock and invoke usb_submit_urb() with GFP_KERNEL.
If the HCD completes in BH (like ehci does) then the context remains
atomic due local_bh_disable() and enabling interrupts does not change
this.
Add an argument to service_outstanding_interrupt() which decides
whether or not it is save to enable interrupts during unlocking and use
GFP_KERNEL or not.
Fixes: c1da59dad0eb ("cdc-wdm: Clear read pipeline in case of error")
Cc: Robert Foss <[email protected]>
Cc: Oliver Neukum <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
---
drivers/usb/class/cdc-wdm.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index a0d284ef3f40..45076b9c7c5e 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -152,7 +152,7 @@ static void wdm_out_callback(struct urb *urb)
}
/* forward declaration */
-static int service_outstanding_interrupt(struct wdm_device *desc);
+static int service_outstanding_interrupt(struct wdm_device *desc, bool en_irq);
static void wdm_in_callback(struct urb *urb)
{
@@ -219,7 +219,7 @@ static void wdm_in_callback(struct urb *urb)
* We should respond to further attempts from the device to send
* data, so that we can get unstuck.
*/
- service_outstanding_interrupt(desc);
+ service_outstanding_interrupt(desc, false);
}
spin_unlock(&desc->iuspin);
@@ -448,7 +448,7 @@ static ssize_t wdm_write
*
* Called with desc->iuspin locked
*/
-static int service_outstanding_interrupt(struct wdm_device *desc)
+static int service_outstanding_interrupt(struct wdm_device *desc, bool en_irq)
{
int rv = 0;
@@ -457,9 +457,15 @@ static int service_outstanding_interrupt(struct wdm_device
*desc)
goto out;
set_bit(WDM_RESPONDING, &desc->flags);
- spin_unlock_irq(&desc->iuspin);
- rv = usb_submit_urb(desc->response, GFP_KERNEL);
- spin_lock_irq(&desc->iuspin);
+ if (en_irq) {
+ spin_unlock_irq(&desc->iuspin);
+ rv = usb_submit_urb(desc->response, GFP_KERNEL);
+ spin_lock_irq(&desc->iuspin);
+ } else {
+ spin_unlock(&desc->iuspin);
+ rv = usb_submit_urb(desc->response, GFP_ATOMIC);
+ spin_lock(&desc->iuspin);
+ }
if (rv) {
dev_err(&desc->intf->dev,
"usb_submit_urb failed with result %d\n", rv);
@@ -544,7 +550,7 @@ static ssize_t wdm_read
if (!desc->reslength) { /* zero length read */
dev_dbg(&desc->intf->dev, "zero length - clearing
WDM_READ\n");
clear_bit(WDM_READ, &desc->flags);
- rv = service_outstanding_interrupt(desc);
+ rv = service_outstanding_interrupt(desc, true);
spin_unlock_irq(&desc->iuspin);
if (rv < 0)
goto err;
@@ -571,7 +577,7 @@ static ssize_t wdm_read
/* in case we had outstanding data */
if (!desc->length) {
clear_bit(WDM_READ, &desc->flags);
- service_outstanding_interrupt(desc);
+ service_outstanding_interrupt(desc, true);
}
spin_unlock_irq(&desc->iuspin);
rv = cntr;
--
2.17.1
--
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