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>

diff --git a/drivers/net/wireless/ath/ath9k/ar9003_paprd.c b/drivers/net/wireless/ath/ath9k/ar9003_paprd.c
index 7c38229ba670a28a624ab521a02820eae581c10a..716db414c258f254263a47238f45aa9fd6c2d813 100644 (file)
--- 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);