diff mbox series

[2/3,V2] rtlwifi: rtl8192de: make arrays static const, makes object smaller

Message ID 20210803144949.79433-2-colin.king@canonical.com (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series [1/3,RESEND] rtlwifi: rtl8192de: Remove redundant variable initializations | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch

Commit Message

Colin King Aug. 3, 2021, 2:49 p.m. UTC 
From: Colin Ian King <colin.king@canonical.com>

Don't populate arrays the stack but instead make them static const. Replace
array channel_info with channel_all since it contains the same data as
channel_all. Makes object code smaller by 961 bytes.

Before:
   text	   data	    bss	    dec	   hex	filename
 128147	  44250	   1024	 173421	 2a56d	../realtek/rtlwifi/rtl8192de/phy.o

After
   text	   data	    bss	    dec	   hex	filename
 127122	  44314	   1024	 172460	 2a1ac	../realtek/rtlwifi/rtl8192de/phy.o

(gcc version 10.2.0)

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---

V2: Remove channel_info and replace with channel_all since it is the
    same as channel_info. Thanks to Joe Perches for spotting this.
---
 .../wireless/realtek/rtlwifi/rtl8192de/phy.c  | 48 ++++++++-----------
 1 file changed, 20 insertions(+), 28 deletions(-)

Comments

Joe Perches Aug. 3, 2021, 3:09 p.m. UTC | #1 
On Tue, 2021-08-03 at 15:49 +0100, Colin King wrote:
> Don't populate arrays the stack but instead make them static const. Replace
> array channel_info with channel_all since it contains the same data as
> channel_all. Makes object code smaller by 961 bytes.
[]
> diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c
[]
> @@ -160,6 +160,15 @@ static u32 targetchnl_2g[TARGET_CHNL_NUM_2G] = {
>  	25711, 25658, 25606, 25554, 25502, 25451, 25328
>  };
> 
> +static const u8 channel_all[59] = {

I don't believe there is a significant value in sizing the array
as 59 instead of letting the compiler count the elements.

> +	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
> +	36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58,
> +	60, 62, 64, 100, 102, 104, 106, 108, 110, 112,
> +	114, 116, 118, 120, 122, 124, 126, 128,	130,
> +	132, 134, 136, 138, 140, 149, 151, 153, 155,
> +	157, 159, 161, 163, 165
> +};
Colin King Aug. 3, 2021, 3:15 p.m. UTC | #2 
On 03/08/2021 16:09, Joe Perches wrote:
> On Tue, 2021-08-03 at 15:49 +0100, Colin King wrote:
>> Don't populate arrays the stack but instead make them static const. Replace
>> array channel_info with channel_all since it contains the same data as
>> channel_all. Makes object code smaller by 961 bytes.
> []
>> diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c
> []
>> @@ -160,6 +160,15 @@ static u32 targetchnl_2g[TARGET_CHNL_NUM_2G] = {
>>  	25711, 25658, 25606, 25554, 25502, 25451, 25328
>>  };
>>
>> +static const u8 channel_all[59] = {
> 
> I don't believe there is a significant value in sizing the array
> as 59 instead of letting the compiler count the elements.

I was reluctant to remove this as I supposed the original had it in for
a purpose, e.g. to ensure that the array was not populated with more
data than intended. Does it make much of a difference?

> 
>> +	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
>> +	36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58,
>> +	60, 62, 64, 100, 102, 104, 106, 108, 110, 112,
>> +	114, 116, 118, 120, 122, 124, 126, 128,	130,
>> +	132, 134, 136, 138, 140, 149, 151, 153, 155,
>> +	157, 159, 161, 163, 165
>> +};
> 
>
Joe Perches Aug. 3, 2021, 3:23 p.m. UTC | #3 
On Tue, 2021-08-03 at 16:15 +0100, Colin Ian King wrote:
> On 03/08/2021 16:09, Joe Perches wrote:
> > On Tue, 2021-08-03 at 15:49 +0100, Colin King wrote:
> > > Don't populate arrays the stack but instead make them static const. Replace
> > > array channel_info with channel_all since it contains the same data as
> > > channel_all. Makes object code smaller by 961 bytes.
> > []
> > > diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c
> > []
> > > @@ -160,6 +160,15 @@ static u32 targetchnl_2g[TARGET_CHNL_NUM_2G] = {
> > >  	25711, 25658, 25606, 25554, 25502, 25451, 25328
> > >  };
> > > 
> > > +static const u8 channel_all[59] = {
> > 
> > I don't believe there is a significant value in sizing the array
> > as 59 instead of letting the compiler count the elements.
> 
> I was reluctant to remove this as I supposed the original had it in for
> a purpose, e.g. to ensure that the array was not populated with more
> data than intended. Does it make much of a difference?
> 
> > 
> > > +	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
> > > +	36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58,
> > > +	60, 62, 64, 100, 102, 104, 106, 108, 110, 112,
> > > +	114, 116, 118, 120, 122, 124, 126, 128,	130,
> > > +	132, 134, 136, 138, 140, 149, 151, 153, 155,
> > > +	157, 159, 161, 163, 165
> > > +};

Dunno.

Maybe not, but I did have to count the elements to see if
it really was 59 or the compiler was adding trailing 0's.

OK I really did a grep to count the commas and added 1...
diff mbox series

Patch

diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c
index 50c2d8f6f9c0..8ae69d914312 100644
--- a/drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c
@@ -160,6 +160,15 @@  static u32 targetchnl_2g[TARGET_CHNL_NUM_2G] = {
 	25711, 25658, 25606, 25554, 25502, 25451, 25328
 };
 
+static const u8 channel_all[59] = {
+	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
+	36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58,
+	60, 62, 64, 100, 102, 104, 106, 108, 110, 112,
+	114, 116, 118, 120, 122, 124, 126, 128,	130,
+	132, 134, 136, 138, 140, 149, 151, 153, 155,
+	157, 159, 161, 163, 165
+};
+
 static u32 _rtl92d_phy_calculate_bit_shift(u32 bitmask)
 {
 	u32 i = ffs(bitmask);
@@ -1354,14 +1363,6 @@  static void _rtl92d_phy_switch_rf_setting(struct ieee80211_hw *hw, u8 channel)
 
 u8 rtl92d_get_rightchnlplace_for_iqk(u8 chnl)
 {
-	u8 channel_all[59] = {
-		1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
-		36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58,
-		60, 62, 64, 100, 102, 104, 106, 108, 110, 112,
-		114, 116, 118, 120, 122, 124, 126, 128,	130,
-		132, 134, 136, 138, 140, 149, 151, 153, 155,
-		157, 159, 161, 163, 165
-	};
 	u8 place = chnl;
 
 	if (chnl > 14) {
@@ -3220,37 +3221,28 @@  void rtl92d_phy_config_macphymode_info(struct ieee80211_hw *hw)
 u8 rtl92d_get_chnlgroup_fromarray(u8 chnl)
 {
 	u8 group;
-	u8 channel_info[59] = {
-		1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
-		36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56,
-		58, 60, 62, 64, 100, 102, 104, 106, 108,
-		110, 112, 114, 116, 118, 120, 122, 124,
-		126, 128, 130, 132, 134, 136, 138, 140,
-		149, 151, 153, 155, 157, 159, 161, 163,
-		165
-	};
 
-	if (channel_info[chnl] <= 3)
+	if (channel_all[chnl] <= 3)
 		group = 0;
-	else if (channel_info[chnl] <= 9)
+	else if (channel_all[chnl] <= 9)
 		group = 1;
-	else if (channel_info[chnl] <= 14)
+	else if (channel_all[chnl] <= 14)
 		group = 2;
-	else if (channel_info[chnl] <= 44)
+	else if (channel_all[chnl] <= 44)
 		group = 3;
-	else if (channel_info[chnl] <= 54)
+	else if (channel_all[chnl] <= 54)
 		group = 4;
-	else if (channel_info[chnl] <= 64)
+	else if (channel_all[chnl] <= 64)
 		group = 5;
-	else if (channel_info[chnl] <= 112)
+	else if (channel_all[chnl] <= 112)
 		group = 6;
-	else if (channel_info[chnl] <= 126)
+	else if (channel_all[chnl] <= 126)
 		group = 7;
-	else if (channel_info[chnl] <= 140)
+	else if (channel_all[chnl] <= 140)
 		group = 8;
-	else if (channel_info[chnl] <= 153)
+	else if (channel_all[chnl] <= 153)
 		group = 9;
-	else if (channel_info[chnl] <= 159)
+	else if (channel_all[chnl] <= 159)
 		group = 10;
 	else
 		group = 11;