[PATCH] atl1c: Fix work event interrupt/task races
DORMANTno replies
From: Tim Gardner <hidden>
Date: 2011-04-20 19:31:31
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
commit eab846b1823e05a045a28d2c87e219ef1b6e3c49
Author: Tim Gardner [off-list ref]
Date: Wed Apr 20 11:31:09 2011 -0600
atl1c: Fix work event interrupt/task races
The mechanism used to initiate work events from the interrupt
handler has a classic read/modify/write race between the interrupt
handler that sets the condition, and the worker task that reads and
clears the condition. Close these races by using atomic
bit fields.
Cc: stable@kernel.org
Cc: Jie Yang [off-list ref]
Signed-off-by: Tim Gardner [off-list ref]
diff --git a/drivers/net/atl1c/atl1c.h b/drivers/net/atl1c/atl1c.h
index 9ab5809..dec8110 100644
--- a/drivers/net/atl1c/atl1c.h
+++ b/drivers/net/atl1c/atl1c.h@@ -566,9 +566,9 @@ struct atl1c_adapter { #define __AT_TESTING 0x0001 #define __AT_RESETTING 0x0002 #define __AT_DOWN 0x0003 - u8 work_event; -#define ATL1C_WORK_EVENT_RESET 0x01 -#define ATL1C_WORK_EVENT_LINK_CHANGE 0x02 + unsigned long work_event; +#define ATL1C_WORK_EVENT_RESET 0 +#define ATL1C_WORK_EVENT_LINK_CHANGE 1 u32 msg_enable; bool have_msi;
diff --git a/drivers/net/atl1c/atl1c_main.c b/drivers/net/atl1c/atl1c_main.c
index 3824382..dffc7f7 100644
--- a/drivers/net/atl1c/atl1c_main.c
+++ b/drivers/net/atl1c/atl1c_main.c@@ -325,7 +325,7 @@ static void atl1c_link_chg_event(struct atl1c_adapter *adapter) } } - adapter->work_event |= ATL1C_WORK_EVENT_LINK_CHANGE; + set_bit(ATL1C_WORK_EVENT_LINK_CHANGE, &adapter->work_event); schedule_work(&adapter->common_task); }
@@ -337,20 +337,16 @@ static void atl1c_common_task(struct work_struct *work) adapter = container_of(work, struct atl1c_adapter, common_task); netdev = adapter->netdev; - if (adapter->work_event & ATL1C_WORK_EVENT_RESET) { - adapter->work_event &= ~ATL1C_WORK_EVENT_RESET; + if (test_and_clear_bit(ATL1C_WORK_EVENT_RESET, &adapter->work_event)) { netif_device_detach(netdev); atl1c_down(adapter); atl1c_up(adapter); netif_device_attach(netdev); - return; } - if (adapter->work_event & ATL1C_WORK_EVENT_LINK_CHANGE) { - adapter->work_event &= ~ATL1C_WORK_EVENT_LINK_CHANGE; + if (test_and_clear_bit(ATL1C_WORK_EVENT_LINK_CHANGE, + &adapter->work_event)) atl1c_check_link_status(adapter); - } - return; }
@@ -369,7 +365,7 @@ static void atl1c_tx_timeout(struct net_device *netdev) struct atl1c_adapter *adapter = netdev_priv(netdev); /* Do the reset outside of interrupt context */ - adapter->work_event |= ATL1C_WORK_EVENT_RESET; + set_bit(ATL1C_WORK_EVENT_RESET, &adapter->work_event); schedule_work(&adapter->common_task); }