2017-09-12 11:38:39

by Colin King

Subject: [PATCH] usb: storage: make const arrays static, reduces object code size

From: Colin Ian King <[email protected]>

Don't populate const arrays on the stack, instead make them
static. Makes the object code smaller by over 1070 bytes:

Before:
text data bss dec hex filename
3505 880 0 4385 1121 drivers/usb/storage/option_ms.o

After:
text data bss dec hex filename
2269 1040 0 3309 ced drivers/usb/storage/option_ms.o

Signed-off-by: Colin Ian King <[email protected]>
---
drivers/usb/storage/option_ms.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/storage/option_ms.c b/drivers/usb/storage/option_ms.c
index 57282f12317b..4a73cd4783ae 100644
--- a/drivers/usb/storage/option_ms.c
+++ b/drivers/usb/storage/option_ms.c
@@ -41,7 +41,7 @@ MODULE_PARM_DESC(option_zero_cd, "ZeroCD mode (1=Force Modem (default),"

static int option_rezero(struct us_data *us)
{
- const unsigned char rezero_msg[] = {
+ static const unsigned char rezero_msg[] = {
0x55, 0x53, 0x42, 0x43, 0x78, 0x56, 0x34, 0x12,
0x01, 0x00, 0x00, 0x00, 0x80, 0x00, 0x06, 0x01,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
@@ -87,7 +87,7 @@ static int option_rezero(struct us_data *us)

static int option_inquiry(struct us_data *us)
{
- const unsigned char inquiry_msg[] = {
+ static const unsigned char inquiry_msg[] = {
0x55, 0x53, 0x42, 0x43, 0x12, 0x34, 0x56, 0x78,
0x24, 0x00, 0x00, 0x00, 0x80, 0x00, 0x06, 0x12,
0x00, 0x00, 0x00, 0x24, 0x00, 0x00, 0x00, 0x00,
--
2.14.1

2017-09-13 03:31:13

by Alan Stern

Subject: Re: [PATCH] usb: storage: make const arrays static, reduces object code size

On Tue, 12 Sep 2017, Colin King wrote:

> From: Colin Ian King <[email protected]>
>
> Don't populate const arrays on the stack, instead make them
> static. Makes the object code smaller by over 1070 bytes:
>
> Before:
> text data bss dec hex filename
> 3505 880 0 4385 1121 drivers/usb/storage/option_ms.o
>
> After:
> text data bss dec hex filename
> 2269 1040 0 3309 ced drivers/usb/storage/option_ms.o
>
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> drivers/usb/storage/option_ms.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/storage/option_ms.c b/drivers/usb/storage/option_ms.c
> index 57282f12317b..4a73cd4783ae 100644
> --- a/drivers/usb/storage/option_ms.c
> +++ b/drivers/usb/storage/option_ms.c
> @@ -41,7 +41,7 @@ MODULE_PARM_DESC(option_zero_cd, "ZeroCD mode (1=Force Modem (default),"
>
> static int option_rezero(struct us_data *us)
> {
> - const unsigned char rezero_msg[] = {
> + static const unsigned char rezero_msg[] = {
> 0x55, 0x53, 0x42, 0x43, 0x78, 0x56, 0x34, 0x12,
> 0x01, 0x00, 0x00, 0x00, 0x80, 0x00, 0x06, 0x01,
> 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> @@ -87,7 +87,7 @@ static int option_rezero(struct us_data *us)
>
> static int option_inquiry(struct us_data *us)
> {
> - const unsigned char inquiry_msg[] = {
> + static const unsigned char inquiry_msg[] = {
> 0x55, 0x53, 0x42, 0x43, 0x12, 0x34, 0x56, 0x78,
> 0x24, 0x00, 0x00, 0x00, 0x80, 0x00, 0x06, 0x12,
> 0x00, 0x00, 0x00, 0x24, 0x00, 0x00, 0x00, 0x00,

Acked-by: Alan Stern <[email protected]>