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ath9k_htc: Handle WMI timeouts properly

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If a WMI command has timed out for some reason,
a late WMI response would end up updating the
response region of a new WMI request that has been
issued in the meantime.

Fix this race condition by dropping a WMI response
if a new WMI command has been issued.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Sujith 2010-04-16 11:54:01 +05:30 committed by John W. Linville
parent eac8e385e9
commit 6ce34ec11c
2 changed files with 14 additions and 0 deletions
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13
drivers/net/wireless/ath/ath9k/wmi.c
View File

@ -204,6 +204,14 @@ static void ath9k_wmi_ctrl_rx(void *priv, struct sk_buff *skb,
return;
}
/* Check if there has been a timeout. */
spin_lock(&wmi->wmi_lock);
if (cmd_id != wmi->last_cmd_id) {
spin_unlock(&wmi->wmi_lock);
goto free_skb;
}
spin_unlock(&wmi->wmi_lock);
/* WMI command response */
ath9k_wmi_rsp_callback(wmi, skb);
@ -266,6 +274,7 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id,
struct sk_buff *skb;
u8 *data;
int time_left, ret = 0;
unsigned long flags;
if (!wmi)
return -EINVAL;
@ -297,6 +306,10 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id,
if (ret)
goto out;
spin_lock_irqsave(&wmi->wmi_lock, flags);
wmi->last_cmd_id = cmd_id;
spin_unlock_irqrestore(&wmi->wmi_lock, flags);
time_left = wait_for_completion_timeout(&wmi->cmd_wait, timeout);
if (!time_left) {
ath_print(common, ATH_DBG_WMI,

1
drivers/net/wireless/ath/ath9k/wmi.h
View File

@ -97,6 +97,7 @@ struct wmi {
enum htc_endpoint_id ctrl_epid;
struct mutex op_mutex;
struct completion cmd_wait;
enum wmi_cmd_id last_cmd_id;
u16 tx_seq_id;
u8 *cmd_rsp_buf;
u32 cmd_rsp_len;