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>

1 files changed, 7 insertions, 3 deletions

diff --git a/drivers/net/wimax/i2400m/driver.c b/drivers/net/wimax/i2400m/driver.c
index 810eda7dbdb..10673af5a7f 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);