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authorOliver Neukum <oneukum@suse.com>2020-04-15 17:13:58 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-04-29 16:31:33 +0200
commit465f0c0b5306bcae604216dd4363d003554f886c (patch)
tree192e118294dccd05abb6dd9039ae3b00d20ab77e
parent681c2486f9f9a56dc8e851245838b001ad326d35 (diff)
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cdc-acm: introduce a cool down
commit a4e7279cd1d19f48f0af2a10ed020febaa9ac092 upstream. Immediate submission in case of a babbling device can lead to a busy loop. Introducing a delayed work. Signed-off-by: Oliver Neukum <oneukum@suse.com> Cc: stable <stable@vger.kernel.org> Tested-by: Jonas Karlsson <jonas.karlsson@actia.se> Link: https://lore.kernel.org/r/20200415151358.32664-2-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/class/cdc-acm.c30
-rw-r--r--drivers/usb/class/cdc-acm.h5
2 files changed, 32 insertions, 3 deletions
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 162ef29cf0f0..10ba1b4f0dbf 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -412,9 +412,12 @@ static void acm_ctrl_irq(struct urb *urb)
exit:
retval = usb_submit_urb(urb, GFP_ATOMIC);
- if (retval && retval != -EPERM)
+ if (retval && retval != -EPERM && retval != -ENODEV)
dev_err(&acm->control->dev,
"%s - usb_submit_urb failed: %d\n", __func__, retval);
+ else
+ dev_vdbg(&acm->control->dev,
+ "control resubmission terminated %d\n", retval);
}
static int acm_submit_read_urb(struct acm *acm, int index, gfp_t mem_flags)
@@ -430,6 +433,8 @@ static int acm_submit_read_urb(struct acm *acm, int index, gfp_t mem_flags)
dev_err(&acm->data->dev,
"urb %d failed submission with %d\n",
index, res);
+ } else {
+ dev_vdbg(&acm->data->dev, "intended failure %d\n", res);
}
set_bit(index, &acm->read_urbs_free);
return res;
@@ -472,6 +477,7 @@ static void acm_read_bulk_callback(struct urb *urb)
int status = urb->status;
bool stopped = false;
bool stalled = false;
+ bool cooldown = false;
dev_vdbg(&acm->data->dev, "got urb %d, len %d, status %d\n",
rb->index, urb->actual_length, status);
@@ -498,6 +504,14 @@ static void acm_read_bulk_callback(struct urb *urb)
__func__, status);
stopped = true;
break;
+ case -EOVERFLOW:
+ case -EPROTO:
+ dev_dbg(&acm->data->dev,
+ "%s - cooling babbling device\n", __func__);
+ usb_mark_last_busy(acm->dev);
+ set_bit(rb->index, &acm->urbs_in_error_delay);
+ cooldown = true;
+ break;
default:
dev_dbg(&acm->data->dev,
"%s - nonzero urb status received: %d\n",
@@ -519,9 +533,11 @@ static void acm_read_bulk_callback(struct urb *urb)
*/
smp_mb__after_atomic();
- if (stopped || stalled) {
+ if (stopped || stalled || cooldown) {
if (stalled)
schedule_work(&acm->work);
+ else if (cooldown)
+ schedule_delayed_work(&acm->dwork, HZ / 2);
return;
}
@@ -573,6 +589,12 @@ static void acm_softint(struct work_struct *work)
}
}
+ if (test_and_clear_bit(ACM_ERROR_DELAY, &acm->flags)) {
+ for (i = 0; i < ACM_NR; i++)
+ if (test_and_clear_bit(i, &acm->urbs_in_error_delay))
+ acm_submit_read_urb(acm, i, GFP_NOIO);
+ }
+
if (test_and_clear_bit(EVENT_TTY_WAKEUP, &acm->flags))
tty_port_tty_wakeup(&acm->port);
}
@@ -1365,6 +1387,7 @@ made_compressed_probe:
acm->readsize = readsize;
acm->rx_buflimit = num_rx_buf;
INIT_WORK(&acm->work, acm_softint);
+ INIT_DELAYED_WORK(&acm->dwork, acm_softint);
init_waitqueue_head(&acm->wioctl);
spin_lock_init(&acm->write_lock);
spin_lock_init(&acm->read_lock);
@@ -1574,6 +1597,7 @@ static void acm_disconnect(struct usb_interface *intf)
acm_kill_urbs(acm);
cancel_work_sync(&acm->work);
+ cancel_delayed_work_sync(&acm->dwork);
tty_unregister_device(acm_tty_driver, acm->minor);
@@ -1616,6 +1640,8 @@ static int acm_suspend(struct usb_interface *intf, pm_message_t message)
acm_kill_urbs(acm);
cancel_work_sync(&acm->work);
+ cancel_delayed_work_sync(&acm->dwork);
+ acm->urbs_in_error_delay = 0;
return 0;
}
diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index 515aad0847ee..30380d28a504 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -108,8 +108,11 @@ struct acm {
unsigned long flags;
# define EVENT_TTY_WAKEUP 0
# define EVENT_RX_STALL 1
+# define ACM_ERROR_DELAY 3
+ unsigned long urbs_in_error_delay; /* these need to be restarted after a delay */
struct usb_cdc_line_coding line; /* bits, stop, parity */
- struct work_struct work; /* work queue entry for line discipline waking up */
+ struct work_struct work; /* work queue entry for various purposes*/
+ struct delayed_work dwork; /* for cool downs needed in error recovery */
unsigned int ctrlin; /* input control lines (DCD, DSR, RI, break, overruns) */
unsigned int ctrlout; /* output control lines (DTR, RTS) */
struct async_icount iocount; /* counters for control line changes */