wimax/i2400m: fix deadlock: don't do BUS reset under i2400m->init_mutex
Since the addition of the pre/post reset handlers, it became clear
that we cannot do a I2400M-RT-BUS type reset while holding the
init_mutex, as in the case of USB, it will deadlock when trying to
call i2400m_pre_reset().
Thus, the following changes:
- clarify the fact that calling bus_reset() w/ I2400M_RT_BUS while
holding init_mutex is a no-no.
- i2400m_dev_reset_handle() will do a BUS reset to recover a gone
device after unlocking init_mutex.
- in the USB reset implementation, when cold and warm reset fails,
fallback to QUEUING a usb reset, not executing a USB reset, so it
happens from another context and does not deadlock.
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
diff --git a/drivers/net/wimax/i2400m/usb.c b/drivers/net/wimax/i2400m/usb.c
index 8b246cc..418db12 100644
--- a/drivers/net/wimax/i2400m/usb.c
+++ b/drivers/net/wimax/i2400m/usb.c
@@ -254,7 +254,6 @@
sizeof(i2400m_COLD_BOOT_BARKER),
i2400mu->endpoint_cfg.reset_cold);
else if (rt == I2400M_RT_BUS) {
-do_bus_reset:
result = usb_reset_device(i2400mu->usb_dev);
switch (result) {
case 0:
@@ -262,7 +261,7 @@
case -ENODEV:
case -ENOENT:
case -ESHUTDOWN:
- result = rt == I2400M_RT_WARM ? -ENODEV : 0;
+ result = 0;
break; /* We assume the device is disconnected */
default:
dev_err(dev, "USB reset failed (%d), giving up!\n",
@@ -275,10 +274,17 @@
if (result < 0
&& result != -EINVAL /* device is gone */
&& rt != I2400M_RT_BUS) {
+ /*
+ * Things failed -- resort to lower level reset, that
+ * we queue in another context; the reason for this is
+ * that the pre and post reset functionality requires
+ * the i2400m->init_mutex; RT_WARM and RT_COLD can
+ * come from areas where i2400m->init_mutex is taken.
+ */
dev_err(dev, "%s reset failed (%d); trying USB reset\n",
rt == I2400M_RT_WARM ? "warm" : "cold", result);
- rt = I2400M_RT_BUS;
- goto do_bus_reset;
+ usb_queue_reset_device(i2400mu->usb_iface);
+ result = -ENODEV;
}
d_fnend(3, dev, "(i2400m %p rt %u) = %d\n", i2400m, rt, result);
return result;