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From:   Stanislaw Gruszka <sgruszka@redhat.com>
To:     linux-wireless@vger.kernel.org
Cc:     Yan-Hsuan Chuang <yhchuang@realtek.com>
Subject: [PATCH 5.1] rtw88: fix subscript above array bounds compiler warning
Date:   Mon,  6 May 2019 09:39:17 +0200
Message-Id: <20190506073917.10106-1-sgruszka@redhat.com>
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Sender: linux-wireless-owner@vger.kernel.org
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My compiler complains about:

drivers/net/wireless/realtek/rtw88/phy.c: In function ‘rtw_phy_rf_power_2_rssi’:
drivers/net/wireless/realtek/rtw88/phy.c:430:26: warning: array subscript is above array bounds [-Warray-bounds]
  linear = db_invert_table[i][j];

According to comment power_db should be in range 1 ~ 96 .
To fix add check for boundaries before access the array.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
---
RFC -> v1
- add check before accessing the array insted of
  rtw_phy_power_2_db() change.
v1 -> v2:
- return 1 for power_db < 1

 drivers/net/wireless/realtek/rtw88/phy.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/wireless/realtek/rtw88/phy.c b/drivers/net/wireless/realtek/rtw88/phy.c
index 4381b360b5b5..9ca52a4d025a 100644
--- a/drivers/net/wireless/realtek/rtw88/phy.c
+++ b/drivers/net/wireless/realtek/rtw88/phy.c
@@ -423,6 +423,11 @@ static u64 rtw_phy_db_2_linear(u8 power_db)
 	u8 i, j;
 	u64 linear;
 
+	if (power_db > 96)
+		power_db = 96;
+	else if (power_db < 1)
+		return 1;
+
 	/* 1dB ~ 96dB */
 	i = (power_db - 1) >> 3;
 	j = (power_db - 1) - (i << 3);
-- 
2.20.1