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* [PATCH 1/1] wireless: move ifs' in _rtl92c_store_pwrIndex_diffrate_offset into elseif statements
@ 2012-01-30  6:50 Devendra.Naga
  2012-01-30 23:38 ` Larry Finger
  2012-02-05  8:12 ` Jan Ceuleers
  0 siblings, 2 replies; 5+ messages in thread
From: Devendra.Naga @ 2012-01-30  6:50 UTC (permalink / raw)
  To: Larry.Finger, chaoming_li, linville, paul.gortmaker, joe,
	linux-wireless, netdev, linux-kernel
  Cc: Devendra.Naga

From: "Devendra.Naga" <devendra.aaru@gmail.com>

        The regaddr is compared against different rates in each case and the powerlevels are set
        accordingly. as this can match for the first if and we still check for other powerlevels too,
        use else if ratherthan using if statements
Signed-off-by: Devendra.Naga <devendra.aaru@gmail.com>
---
 drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c |   47 +++++++------------
 1 files changed, 17 insertions(+), 30 deletions(-)

diff --git a/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c b/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c
index 22e998d..cb11e5a 100644
--- a/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c
+++ b/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c
@@ -260,106 +260,93 @@ void _rtl92c_store_pwrIndex_diffrate_offset(struct ieee80211_hw *hw,
 			 "MCSTxPowerLevelOriginalOffset[%d][0] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][0]);
-	}
-	if (regaddr == RTXAGC_A_RATE54_24) {
+	} else if (regaddr == RTXAGC_A_RATE54_24) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][1] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][1] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][1]);
-	}
-	if (regaddr == RTXAGC_A_CCK1_MCS32) {
+	} else if (regaddr == RTXAGC_A_CCK1_MCS32) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][6] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][6] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][6]);
-	}
-	if (regaddr == RTXAGC_B_CCK11_A_CCK2_11 && bitmask == 0xffffff00) {
+	} else if (regaddr == RTXAGC_B_CCK11_A_CCK2_11 &&
+		bitmask == 0xffffff00) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][7] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][7] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][7]);
-	}
-	if (regaddr == RTXAGC_A_MCS03_MCS00) {
+	} else if (regaddr == RTXAGC_A_MCS03_MCS00) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][2] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][2] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][2]);
-	}
-	if (regaddr == RTXAGC_A_MCS07_MCS04) {
+	} else if (regaddr == RTXAGC_A_MCS07_MCS04) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][3] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][3] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][3]);
-	}
-	if (regaddr == RTXAGC_A_MCS11_MCS08) {
+	} else if (regaddr == RTXAGC_A_MCS11_MCS08) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][4] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][4] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][4]);
-	}
-	if (regaddr == RTXAGC_A_MCS15_MCS12) {
+	} else if (regaddr == RTXAGC_A_MCS15_MCS12) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][5] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][5] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][5]);
-	}
-	if (regaddr == RTXAGC_B_RATE18_06) {
+	} else if (regaddr == RTXAGC_B_RATE18_06) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][8] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][8] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][8]);
-	}
-	if (regaddr == RTXAGC_B_RATE54_24) {
+	} else if (regaddr == RTXAGC_B_RATE54_24) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][9] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][9] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][9]);
-	}
-	if (regaddr == RTXAGC_B_CCK1_55_MCS32) {
+	} else if (regaddr == RTXAGC_B_CCK1_55_MCS32) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][14] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][14] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][14]);
-	}
-	if (regaddr == RTXAGC_B_CCK11_A_CCK2_11 && bitmask == 0x000000ff) {
+	} else if (regaddr == RTXAGC_B_CCK11_A_CCK2_11 &&
+		bitmask == 0x000000ff) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][15] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][15] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][15]);
-	}
-	if (regaddr == RTXAGC_B_MCS03_MCS00) {
+	} else if (regaddr == RTXAGC_B_MCS03_MCS00) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][10] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][10] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][10]);
-	}
-	if (regaddr == RTXAGC_B_MCS07_MCS04) {
+	} else if (regaddr == RTXAGC_B_MCS07_MCS04) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][11] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][11] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][11]);
-	}
-	if (regaddr == RTXAGC_B_MCS11_MCS08) {
+	} else if (regaddr == RTXAGC_B_MCS11_MCS08) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][12] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][12] = 0x%x\n",
 			 rtlphy->pwrgroup_cnt,
 			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][12]);
-	}
-	if (regaddr == RTXAGC_B_MCS15_MCS12) {
+	} else if (regaddr == RTXAGC_B_MCS15_MCS12) {
 		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][13] = data;
 		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
 			 "MCSTxPowerLevelOriginalOffset[%d][13] = 0x%x\n",
-- 
1.7.5.4


^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH 1/1] wireless: move ifs' in _rtl92c_store_pwrIndex_diffrate_offset into elseif statements
  2012-01-30  6:50 [PATCH 1/1] wireless: move ifs' in _rtl92c_store_pwrIndex_diffrate_offset into elseif statements Devendra.Naga
@ 2012-01-30 23:38 ` Larry Finger
  2012-02-05  8:12 ` Jan Ceuleers
  1 sibling, 0 replies; 5+ messages in thread
From: Larry Finger @ 2012-01-30 23:38 UTC (permalink / raw)
  To: Devendra.Naga
  Cc: chaoming_li, linville, paul.gortmaker, joe, linux-wireless,
	netdev, linux-kernel

On 01/30/2012 12:50 AM, Devendra.Naga wrote:
> From: "Devendra.Naga"<devendra.aaru@gmail.com>
>
>          The regaddr is compared against different rates in each case and the powerlevels are set
>          accordingly. as this can match for the first if and we still check for other powerlevels too,
>          use else if ratherthan using if statements
> Signed-off-by: Devendra.Naga<devendra.aaru@gmail.com>
> ---
>   drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c |   47 +++++++------------
>   1 files changed, 17 insertions(+), 30 deletions(-)

Another bad patch title. The component changed is rtlwifi: rtl8192c:, not wireless.

Larry

>
> diff --git a/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c b/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c
> index 22e998d..cb11e5a 100644
> --- a/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c
> +++ b/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c
> @@ -260,106 +260,93 @@ void _rtl92c_store_pwrIndex_diffrate_offset(struct ieee80211_hw *hw,
>   			 "MCSTxPowerLevelOriginalOffset[%d][0] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][0]);
> -	}
> -	if (regaddr == RTXAGC_A_RATE54_24) {
> +	} else if (regaddr == RTXAGC_A_RATE54_24) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][1] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][1] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][1]);
> -	}
> -	if (regaddr == RTXAGC_A_CCK1_MCS32) {
> +	} else if (regaddr == RTXAGC_A_CCK1_MCS32) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][6] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][6] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][6]);
> -	}
> -	if (regaddr == RTXAGC_B_CCK11_A_CCK2_11&&  bitmask == 0xffffff00) {
> +	} else if (regaddr == RTXAGC_B_CCK11_A_CCK2_11&&
> +		bitmask == 0xffffff00) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][7] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][7] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][7]);
> -	}
> -	if (regaddr == RTXAGC_A_MCS03_MCS00) {
> +	} else if (regaddr == RTXAGC_A_MCS03_MCS00) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][2] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][2] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][2]);
> -	}
> -	if (regaddr == RTXAGC_A_MCS07_MCS04) {
> +	} else if (regaddr == RTXAGC_A_MCS07_MCS04) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][3] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][3] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][3]);
> -	}
> -	if (regaddr == RTXAGC_A_MCS11_MCS08) {
> +	} else if (regaddr == RTXAGC_A_MCS11_MCS08) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][4] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][4] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][4]);
> -	}
> -	if (regaddr == RTXAGC_A_MCS15_MCS12) {
> +	} else if (regaddr == RTXAGC_A_MCS15_MCS12) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][5] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][5] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][5]);
> -	}
> -	if (regaddr == RTXAGC_B_RATE18_06) {
> +	} else if (regaddr == RTXAGC_B_RATE18_06) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][8] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][8] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][8]);
> -	}
> -	if (regaddr == RTXAGC_B_RATE54_24) {
> +	} else if (regaddr == RTXAGC_B_RATE54_24) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][9] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][9] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][9]);
> -	}
> -	if (regaddr == RTXAGC_B_CCK1_55_MCS32) {
> +	} else if (regaddr == RTXAGC_B_CCK1_55_MCS32) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][14] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][14] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][14]);
> -	}
> -	if (regaddr == RTXAGC_B_CCK11_A_CCK2_11&&  bitmask == 0x000000ff) {
> +	} else if (regaddr == RTXAGC_B_CCK11_A_CCK2_11&&
> +		bitmask == 0x000000ff) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][15] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][15] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][15]);
> -	}
> -	if (regaddr == RTXAGC_B_MCS03_MCS00) {
> +	} else if (regaddr == RTXAGC_B_MCS03_MCS00) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][10] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][10] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][10]);
> -	}
> -	if (regaddr == RTXAGC_B_MCS07_MCS04) {
> +	} else if (regaddr == RTXAGC_B_MCS07_MCS04) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][11] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][11] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][11]);
> -	}
> -	if (regaddr == RTXAGC_B_MCS11_MCS08) {
> +	} else if (regaddr == RTXAGC_B_MCS11_MCS08) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][12] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][12] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][12]);
> -	}
> -	if (regaddr == RTXAGC_B_MCS15_MCS12) {
> +	} else if (regaddr == RTXAGC_B_MCS15_MCS12) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][13] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][13] = 0x%x\n",


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH 1/1] wireless: move ifs' in _rtl92c_store_pwrIndex_diffrate_offset into elseif statements
  2012-01-30  6:50 [PATCH 1/1] wireless: move ifs' in _rtl92c_store_pwrIndex_diffrate_offset into elseif statements Devendra.Naga
  2012-01-30 23:38 ` Larry Finger
@ 2012-02-05  8:12 ` Jan Ceuleers
  2012-02-05 16:05   ` Larry Finger
  1 sibling, 1 reply; 5+ messages in thread
From: Jan Ceuleers @ 2012-02-05  8:12 UTC (permalink / raw)
  To: Devendra.Naga
  Cc: Larry.Finger, chaoming_li, linville, paul.gortmaker, joe,
	linux-wireless, netdev, linux-kernel

On 01/30/2012 07:50 AM, Devendra.Naga wrote:
> From: "Devendra.Naga"<devendra.aaru@gmail.com>
>
>          The regaddr is compared against different rates in each case and the powerlevels are set
>          accordingly. as this can match for the first if and we still check for other powerlevels too,
>          use else if ratherthan using if statements
> Signed-off-by: Devendra.Naga<devendra.aaru@gmail.com>
If this is correct, and I'm not saying it is or isn't, would it not be 
clearer to turn this whole section into a switch statement? The cases 
that requiring fiddling with the bitmask would need to be dealt with in 
the default: case.

Why was it written as a series of if statements to begin with: can (or 
could) any of these if statements change the value of regaddr such that 
later ifs evaluate differently? From reading only the patch the answer 
seems to be "no", so that looks good.

Or what about turning this into a data-driven section? It looks like 
values of regaddr are being translated into offsets into 
rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt]. Can this be done with a lookup 
table?

> ---
>   drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c |   47 +++++++------------
>   1 files changed, 17 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c b/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c
> index 22e998d..cb11e5a 100644
> --- a/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c
> +++ b/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c
> @@ -260,106 +260,93 @@ void _rtl92c_store_pwrIndex_diffrate_offset(struct ieee80211_hw *hw,
>   			 "MCSTxPowerLevelOriginalOffset[%d][0] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][0]);
> -	}
> -	if (regaddr == RTXAGC_A_RATE54_24) {
> +	} else if (regaddr == RTXAGC_A_RATE54_24) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][1] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][1] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][1]);
> -	}
> -	if (regaddr == RTXAGC_A_CCK1_MCS32) {
> +	} else if (regaddr == RTXAGC_A_CCK1_MCS32) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][6] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][6] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][6]);
> -	}
> -	if (regaddr == RTXAGC_B_CCK11_A_CCK2_11&&  bitmask == 0xffffff00) {
> +	} else if (regaddr == RTXAGC_B_CCK11_A_CCK2_11&&
> +		bitmask == 0xffffff00) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][7] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][7] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][7]);
> -	}
> -	if (regaddr == RTXAGC_A_MCS03_MCS00) {
> +	} else if (regaddr == RTXAGC_A_MCS03_MCS00) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][2] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][2] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][2]);
> -	}
> -	if (regaddr == RTXAGC_A_MCS07_MCS04) {
> +	} else if (regaddr == RTXAGC_A_MCS07_MCS04) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][3] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][3] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][3]);
> -	}
> -	if (regaddr == RTXAGC_A_MCS11_MCS08) {
> +	} else if (regaddr == RTXAGC_A_MCS11_MCS08) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][4] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][4] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][4]);
> -	}
> -	if (regaddr == RTXAGC_A_MCS15_MCS12) {
> +	} else if (regaddr == RTXAGC_A_MCS15_MCS12) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][5] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][5] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][5]);
> -	}
> -	if (regaddr == RTXAGC_B_RATE18_06) {
> +	} else if (regaddr == RTXAGC_B_RATE18_06) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][8] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][8] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][8]);
> -	}
> -	if (regaddr == RTXAGC_B_RATE54_24) {
> +	} else if (regaddr == RTXAGC_B_RATE54_24) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][9] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][9] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][9]);
> -	}
> -	if (regaddr == RTXAGC_B_CCK1_55_MCS32) {
> +	} else if (regaddr == RTXAGC_B_CCK1_55_MCS32) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][14] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][14] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][14]);
> -	}
> -	if (regaddr == RTXAGC_B_CCK11_A_CCK2_11&&  bitmask == 0x000000ff) {
> +	} else if (regaddr == RTXAGC_B_CCK11_A_CCK2_11&&
> +		bitmask == 0x000000ff) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][15] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][15] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][15]);
> -	}
> -	if (regaddr == RTXAGC_B_MCS03_MCS00) {
> +	} else if (regaddr == RTXAGC_B_MCS03_MCS00) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][10] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][10] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][10]);
> -	}
> -	if (regaddr == RTXAGC_B_MCS07_MCS04) {
> +	} else if (regaddr == RTXAGC_B_MCS07_MCS04) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][11] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][11] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][11]);
> -	}
> -	if (regaddr == RTXAGC_B_MCS11_MCS08) {
> +	} else if (regaddr == RTXAGC_B_MCS11_MCS08) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][12] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][12] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][12]);
> -	}
> -	if (regaddr == RTXAGC_B_MCS15_MCS12) {
> +	} else if (regaddr == RTXAGC_B_MCS15_MCS12) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][13] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][13] = 0x%x\n",


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH 1/1] wireless: move ifs' in _rtl92c_store_pwrIndex_diffrate_offset into elseif statements
  2012-02-05  8:12 ` Jan Ceuleers
@ 2012-02-05 16:05   ` Larry Finger
  2012-02-06 11:26     ` David Laight
  0 siblings, 1 reply; 5+ messages in thread
From: Larry Finger @ 2012-02-05 16:05 UTC (permalink / raw)
  To: Jan Ceuleers
  Cc: Devendra.Naga, chaoming_li, linville, paul.gortmaker, joe,
	linux-wireless, netdev, linux-kernel

On 02/05/2012 02:12 AM, Jan Ceuleers wrote:
> On 01/30/2012 07:50 AM, Devendra.Naga wrote:
>> From: "Devendra.Naga"<devendra.aaru@gmail.com>
>>
>> The regaddr is compared against different rates in each case and the
>> powerlevels are set
>> accordingly. as this can match for the first if and we still check for other
>> powerlevels too,
>> use else if ratherthan using if statements
>> Signed-off-by: Devendra.Naga<devendra.aaru@gmail.com>
> If this is correct, and I'm not saying it is or isn't, would it not be clearer
> to turn this whole section into a switch statement? The cases that requiring
> fiddling with the bitmask would need to be dealt with in the default: case.

Yes, it is correct. It might be clearer if it were written as a switch 
statement, but that would be a lot more intrusive. Besides, have you ever looked 
at the way gcc compiles a switch? I have done some reverse engineering, and at 
least some implementations generate code that looks like if .. else if .. .. 
else. I have not looked at the generated code, but I'm quite certain that the 
optimizer in gcc is good enough to know that once it gets a match between 
regaddr and one of the RTXAGC constants, there is no need to test the rest, and 
that the change to "else if" is mostly cosmetic, and will not greatly affect the 
execution.

> Why was it written as a series of if statements to begin with: can (or could)
> any of these if statements change the value of regaddr such that later ifs
> evaluate differently? From reading only the patch the answer seems to be "no",
> so that looks good.

I cannot answer the question of why it was written this way - you would have to 
ask the original authors. As to the possibility of the code changing regaddr, 
you either need to look more carefully at the code, or you need to restudy how C 
works.

> Or what about turning this into a data-driven section? It looks like values of
> regaddr are being translated into offsets into
> rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt]. Can this be done with a lookup table?

I would state it a little differently - the values of regaddr are used to 
determine where in the double-indexed array rtlphy->MCS_TXPWR[][] that the 
quantity "data" should be placed. There are always multiple ways to do anything. 
For the kernel, a major rule is to make minimal changes that are easy to verify. 
The patch in question meets that condition. If this code were in the hot path, 
it might be worth the effort required to do a complete rewrite with the 
associated testing, but in my mind, that effort would be wasted. Something that 
would be easy to do, easy to verify, and would reduce the size of the generated 
code would be

int index;

if (regaddr == RTXAGC_A_RATE18_06) {
	index = 0;
else if (if (regaddr == RTXAGC_A_RATE54_24) {
	index = 1;
.....
}
rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][index] = data;
RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
          "MCSTxPowerLevelOriginalOffset[%d][%d] = 0x%x\n",
          rtlphy->pwrgroup_cnt, index,
          rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][index]);
...

Larry

^ permalink raw reply	[flat|nested] 5+ messages in thread

* RE: [PATCH 1/1] wireless: move ifs' in _rtl92c_store_pwrIndex_diffrate_offset into elseif statements
  2012-02-05 16:05   ` Larry Finger
@ 2012-02-06 11:26     ` David Laight
  0 siblings, 0 replies; 5+ messages in thread
From: David Laight @ 2012-02-06 11:26 UTC (permalink / raw)
  To: Larry Finger, Jan Ceuleers
  Cc: Devendra.Naga, chaoming_li, linville, paul.gortmaker, joe,
	linux-wireless, netdev, linux-kernel

> Yes, it is correct. It might be clearer if it were written as 
> a switch statement, but that would be a lot more intrusive.
> Besides, have you ever looked at the way gcc compiles a switch?

How gcc compiles a switch statement depends (amongst other
things) on whether the labels form a 'dense set' or not.
If they are dense it will usually generate a jump table.
If they are not dense it will compare against the 'middle'
entry first and generate a tree of conditionals.
An 'else if' chain is a linear search.

If the performance of the code matters in can be worth
an explicit test for the common case outside the switch.
Alternatively an 'if else' chain with every conditional
marked 'unlikely' should generate exactly one mispredicted
branch (if you can force static branch prediction).

There are further constraints that apply to some cpus.

Mostly it isn't worth worrying about - although a lot of
code can be significantly sped up by avoiding/containing
register spills and mis-predicted branches.

The code is question seemed to be checking bits, not
an ordinal - so changing to a case might be problematic.
(Could more than one bit bet set????)

	David



^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2012-02-06 11:27 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-01-30  6:50 [PATCH 1/1] wireless: move ifs' in _rtl92c_store_pwrIndex_diffrate_offset into elseif statements Devendra.Naga
2012-01-30 23:38 ` Larry Finger
2012-02-05  8:12 ` Jan Ceuleers
2012-02-05 16:05   ` Larry Finger
2012-02-06 11:26     ` David Laight

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