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wil6210: protect synchronous wmi commands handling 

In case there are multiple WMI commands with the same reply_id,
the following scenario can occur:
- Driver sends the first command to the device
- The reply didn’t get on time and there is timeout
- Reply_id, reply_buf and reply_size are set to 0
- Driver sends second wmi command with the same reply_id as the first
- Driver sets wil->reply_id
- Reply for the first wmi command arrives and handled by wmi_recv_cmd
- As its ID fits the reply_id but the reply_buf is not set yet it is
handled as a reply with event handler, and WARN_ON is printed

This patch guarantee atomic setting of all the reply variables and
prevents the above scenario.

Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
This commit is contained in:
Maya Erez 2016-01-28 19:24:04 +02:00 committed by Kalle Valo
parent 78771d76f8
commit fe5c271e28
1 changed files with 13 additions and 4 deletions
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17
drivers/net/wireless/ath/wil6210/wmi.c
View File

@ -838,6 +838,7 @@ void wmi_recv_cmd(struct wil6210_priv *wil)
struct wil6210_mbox_hdr_wmi *wmi = &evt->event.wmi;
u16 id = le16_to_cpu(wmi->id);
u32 tstamp = le32_to_cpu(wmi->timestamp);
spin_lock_irqsave(&wil->wmi_ev_lock, flags);
if (wil->reply_id && wil->reply_id == id) {
if (wil->reply_buf) {
memcpy(wil->reply_buf, wmi,
@ -845,6 +846,7 @@ void wmi_recv_cmd(struct wil6210_priv *wil)
immed_reply = true;
}
}
spin_unlock_irqrestore(&wil->wmi_ev_lock, flags);
wil_dbg_wmi(wil, "WMI event 0x%04x MID %d @%d msec\n",
id, wmi->mid, tstamp);
@ -888,13 +890,16 @@ int wmi_call(struct wil6210_priv *wil, u16 cmdid, void *buf, u16 len,
mutex_lock(&wil->wmi_mutex);
spin_lock(&wil->wmi_ev_lock);
wil->reply_id = reply_id;
wil->reply_buf = reply;
wil->reply_size = reply_size;
spin_unlock(&wil->wmi_ev_lock);
rc = __wmi_send(wil, cmdid, buf, len);
if (rc)
goto out;
wil->reply_id = reply_id;
wil->reply_buf = reply;
wil->reply_size = reply_size;
remain = wait_for_completion_timeout(&wil->wmi_call,
msecs_to_jiffies(to_msec));
if (0 == remain) {
@ -907,10 +912,14 @@ int wmi_call(struct wil6210_priv *wil, u16 cmdid, void *buf, u16 len,
cmdid, reply_id,
to_msec - jiffies_to_msecs(remain));
}
out:
spin_lock(&wil->wmi_ev_lock);
wil->reply_id = 0;
wil->reply_buf = NULL;
wil->reply_size = 0;
out:
spin_unlock(&wil->wmi_ev_lock);
mutex_unlock(&wil->wmi_mutex);
return rc;