From 2d3fca180710c6832de22c44155ce6a3a4953c6b Mon Sep 17 00:00:00 2001
From: Senthil Balasubramanian <senthilkumar@atheros.com>
Date: Tue, 19 Oct 2010 20:01:41 +0530
Subject: [PATCH] ath9k_hw: Fix divide by zero cases in paprd.
We are not handling all divide by zero cases in paprd.
Add additional checks for divide by zero cases in papard.
This patch has fixes intended for kernel 2.6.36.
Cc: stable@kernel.org
Signed-off-by: Senthil Balasubramanian <senthilkumar@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
---
drivers/net/wireless/ath/ath9k/ar9003_paprd.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/ar9003_paprd.c b/drivers/net/wireless/ath/ath9k/ar9003_paprd.c
index 7c38229ba670a2..716db414c258f2 100644
--- a/drivers/net/wireless/ath/ath9k/ar9003_paprd.c
+++ b/drivers/net/wireless/ath/ath9k/ar9003_paprd.c
@@ -347,6 +347,10 @@ static bool create_pa_curve(u32 *data_L, u32 *data_U, u32 *pa_table, u16 *gain)
(((Y[6] - Y[3]) * 1 << scale_factor) +
(x_est[6] - x_est[3])) / (x_est[6] - x_est[3]);
+ /* prevent division by zero */
+ if (G_fxp == 0)
+ return false;
+
Y_intercept =
(G_fxp * (x_est[0] - x_est[3]) +
(1 << scale_factor)) / (1 << scale_factor) + Y[3];
@@ -356,14 +360,12 @@ static bool create_pa_curve(u32 *data_L, u32 *data_U, u32 *pa_table, u16 *gain)
for (i = 0; i <= 3; i++) {
y_est[i] = i * 32;
-
- /* prevent division by zero */
- if (G_fxp == 0)
- return false;
-
x_est[i] = ((y_est[i] * 1 << scale_factor) + G_fxp) / G_fxp;
}
+ if (y_est[max_index] == 0)
+ return false;
+
x_est_fxp1_nonlin =
x_est[max_index] - ((1 << scale_factor) * y_est[max_index] +
G_fxp) / G_fxp;
@@ -457,6 +459,8 @@ static bool create_pa_curve(u32 *data_L, u32 *data_U, u32 *pa_table, u16 *gain)
Q_scale_B = find_proper_scale(find_expn(abs(scale_B)), 10);
scale_B = scale_B / (1 << Q_scale_B);
+ if (scale_B == 0)
+ return false;
Q_beta = find_proper_scale(find_expn(abs(beta_raw)), 10);
Q_alpha = find_proper_scale(find_expn(abs(alpha_raw)), 10);
beta_raw = beta_raw / (1 << Q_beta);
--
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