wimax/i2400m: if a device reboot happens during probe, handle it

When a device reboot happens when we are under probe, with init_mutex
taken, make sure we can recover. Have dev_reset_handle set boot mode
and i2400m_msg_to_dev() will see it and fail gracefully instead of
timing out.

Found and diagnosed by Cindy H. Kao.

Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>

3 files changed, 5 insertions, 0 deletions

diff --git a/drivers/net/wimax/i2400m/control.c b/drivers/net/wimax/i2400m/control.c
index d8e0cdfa35d5..f9399f2597f3 100644
--- a/drivers/net/wimax/i2400m/control.c
+++ b/drivers/net/wimax/i2400m/control.c
@@ -695,6 +695,7 @@ struct sk_buff *i2400m_msg_to_dev(struct i2400m *i2400m,
         d_fnstart(3, dev, "(i2400m %p buf %p len %zu)\n",
                   i2400m, buf, buf_len);
 
+        rmb();          /* Make sure we see what i2400m_dev_reset_handle() */
         if (i2400m->boot_mode)
                 return ERR_PTR(-ENODEV);
 
diff --git a/drivers/net/wimax/i2400m/driver.c b/drivers/net/wimax/i2400m/driver.c
index 897794c9209e..e8d022d58427 100644
--- a/drivers/net/wimax/i2400m/driver.c
+++ b/drivers/net/wimax/i2400m/driver.c
@@ -610,6 +610,8 @@ out:
  */
 int i2400m_dev_reset_handle(struct i2400m *i2400m)
 {
+        i2400m->boot_mode = 1;
+        wmb();          /* Make sure i2400m_msg_to_dev() sees boot_mode */
         return i2400m_schedule_work(i2400m, __i2400m_dev_reset_handle,
                                     GFP_ATOMIC);
 }
diff --git a/drivers/net/wimax/i2400m/fw.c b/drivers/net/wimax/i2400m/fw.c
index 26924f17f19d..01c926ed309e 100644
--- a/drivers/net/wimax/i2400m/fw.c
+++ b/drivers/net/wimax/i2400m/fw.c
@@ -985,6 +985,7 @@ int i2400m_fw_dnload(struct i2400m *i2400m, const struct i2400m_bcf_hdr *bcf,
         d_fnstart(5, dev, "(i2400m %p bcf %p size %zu)\n",
                   i2400m, bcf, bcf_size);
         i2400m->boot_mode = 1;
+        wmb();          /* Make sure other readers see it */
 hw_reboot:
         if (count-- == 0) {
                 ret = -ERESTARTSYS;
@@ -1033,6 +1034,7 @@ hw_reboot:
         d_printf(2, dev, "fw %s successfully uploaded\n",
                  i2400m->fw_name);
         i2400m->boot_mode = 0;
+        wmb();          /* Make sure i2400m_msg_to_dev() sees boot_mode */
 error_dnload_finalize:
 error_dnload_bcf:
 error_dnload_init: