[ 02/61] rtlwifi: Fix scheduling while atomic bug

Greg Kroah-Hartman
2013-02-12T21:11:54Z

From: Larry Finger <Larry.Finger@lwfinger.net>

commit a5ffbe0a1993a27072742ef7db6cf9839956fce9 upstream.

Kernel commits 41affd5 and 6539306 changed the locking in rtl_lps_leave()
from a spinlock to a mutex by doing the calls indirectly from a work queue
to reduce the time that interrupts were disabled. This change was fine for
most systems; however a scheduling while atomic bug was reported in
https://bugzilla.redhat.com/show_bug.cgi?id=903881. The backtrace indicates
that routine rtl_is_special(), which calls rtl_lps_leave() in three places
was entered in atomic context. These direct calls are replaced by putting a
request on the appropriate work queue.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Reported-and-tested-by: Nathaniel Doherty <ntdoherty@gmail.com>
Cc: Nathaniel Doherty <ntdoherty@gmail.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/wireless/rtlwifi/base.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/net/wireless/rtlwifi/base.c
+++ b/drivers/net/wireless/rtlwifi/base.c
@@ -980,7 +980,8 @@ u8 rtl_is_special_data(struct ieee80211_
is_tx ? "Tx" : "Rx");

if (is_tx) {
- rtl_lps_leave(hw);
+ schedule_work(&rtlpriv->
+ works.lps_leave_work);
ppsc->last_delaylps_stamp_jiffies =
jiffies;
}
@@ -990,7 +991,7 @@ u8 rtl_is_special_data(struct ieee80211_
}
} else if (ETH_P_ARP == ether_type) {
if (is_tx) {
- rtl_lps_leave(hw);
+ schedule_work(&rtlpriv->works.lps_leave_work);
ppsc->last_delaylps_stamp_jiffies = jiffies;
}

@@ -1000,7 +1001,7 @@ u8 rtl_is_special_data(struct ieee80211_
"802.1X %s EAPOL pkt!!\n", is_tx ? "Tx" : "Rx");

if (is_tx) {
- rtl_lps_leave(hw);
+ schedule_work(&rtlpriv->works.lps_leave_work);
ppsc->last_delaylps_stamp_jiffies = jiffies;
}