From 473becac4b310dd720a0f5e07ce149a09467f1a4 Mon Sep 17 00:00:00 2001
From: Miaoqing Pan <miaoqing@codeaurora.org>
Date: Tue, 27 Jun 2017 17:31:54 +0300
Subject: [PATCH] ath9k: avoid potential freezing during random generator read
Git-commit: 473becac4b310dd720a0f5e07ce149a09467f1a4
Patch-mainline: v4.13-rc1
References: FATE#326906

In the worst case, ath9k_rng_stop() may take 10s to stop rng kthread.
The time is too long for users, use wait_event_interruptible_timeout()
instead of msleep_interruptible(), wakup immediately once
kthread_should_stop() is true.

Signed-off-by: Miaoqing Pan <miaoqing@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/wireless/ath/ath9k/rng.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath9k/rng.c b/drivers/net/wireless/ath/ath9k/rng.c
index 73f46fb3e83a..f9d3d6eedd3c 100644
--- a/drivers/net/wireless/ath/ath9k/rng.c
+++ b/drivers/net/wireless/ath/ath9k/rng.c
@@ -24,6 +24,8 @@
 #define ATH9K_RNG_BUF_SIZE	320
 #define ATH9K_RNG_ENTROPY(x)	(((x) * 8 * 10) >> 5) /* quality: 10/32 */
 
+static DECLARE_WAIT_QUEUE_HEAD(rng_queue);
+
 static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size)
 {
 	int i, j;
@@ -85,7 +87,9 @@ static int ath9k_rng_kthread(void *data)
 						 ATH9K_RNG_BUF_SIZE);
 		if (unlikely(!bytes_read)) {
 			delay = ath9k_rng_delay_get(++fail_stats);
-			msleep_interruptible(delay);
+			wait_event_interruptible_timeout(rng_queue,
+							 kthread_should_stop(),
+							 msecs_to_jiffies(delay));
 			continue;
 		}
 
-- 
2.19.2