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 at linux.intel.com>
---
drivers/net/wimax/i2400m/driver.c | 10 +++++++---
drivers/net/wimax/i2400m/i2400m.h | 3 +++
drivers/net/wimax/i2400m/usb.c | 14 ++++++++++----
3 files changed, 20 insertions(+), 7 deletions(-)
diff --git a/drivers/net/wimax/i2400m/driver.c b/drivers/net/wimax/i2400m/driver.c
index 810eda7..10673af 100644
--- a/drivers/net/wimax/i2400m/driver.c
+++ b/drivers/net/wimax/i2400m/driver.c
@@ -765,9 +765,7 @@ void __i2400m_dev_reset_handle(struct work_struct *ws)
wmb(); /* see i2400m->updown's documentation */
dev_err(dev, "%s: cannot start the device: %d\n",
reason, result);
- result = i2400m->bus_reset(i2400m, I2400M_RT_BUS);
- if (result >= 0)
- result = -ENODEV;
+ result = -EUCLEAN;
}
out_unlock:
if (i2400m->reset_ctx) {
@@ -775,6 +773,12 @@ out_unlock:
complete(&ctx->completion);
}
mutex_unlock(&i2400m->init_mutex);
+ if (result == -EUCLEAN) {
+ /* ops, need to clean up [w/ init_mutex not held] */
+ result = i2400m->bus_reset(i2400m, I2400M_RT_BUS);
+ if (result >= 0)
+ result = -ENODEV;
+ }
out:
i2400m_put(i2400m);
kfree(iw);
diff --git a/drivers/net/wimax/i2400m/i2400m.h b/drivers/net/wimax/i2400m/i2400m.h
index 8fc8a0c..f5ed7d5 100644
--- a/drivers/net/wimax/i2400m/i2400m.h
+++ b/drivers/net/wimax/i2400m/i2400m.h
@@ -281,6 +281,9 @@ struct i2400m_barker_db;
* process, so it cannot rely on common infrastructure being laid
* out.
*
+ * IMPORTANT: don't call reset on RT_BUS with i2400m->init_mutex
+ * held, as the .pre/.post reset handlers will deadlock.
+ *
* @bus_bm_retries: [fill] How many times shall a firmware upload /
* device initialization be retried? Different models of the same
* device might need different values, hence it is set by the
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 @@ int i2400mu_bus_reset(struct i2400m *i2400m, enum i2400m_reset_type rt)
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 @@ do_bus_reset:
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 @@ do_bus_reset:
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;
--
1.6.2.5
