[PATCH] usb-storage: Use const to reduce object data size

* [PATCH] usb-storage: Use const to reduce object data size
@ 2020-02-14 18:15 Joe Perches
  2020-02-14 22:01 ` Alan Stern
  2020-02-17  9:40 ` Greg Kroah-Hartman
  0 siblings, 2 replies; 4+ messages in thread
From: Joe Perches @ 2020-02-14 18:15 UTC (permalink / raw)
  To: Alan Stern; +Cc: Greg Kroah-Hartman, linux-usb, usb-storage, linux-kernel

Make structs const to reduce data size ~20KB.

Change function arguments and prototypes as necessary to compile.

$ size (x86-64 defconfig pre)
   text	   data	    bss	    dec	    hex	filename
  12281	  10948	    480	  23709	   5c9d	./drivers/usb/storage/usb.o
    111	  10528	      8	  10647	   2997	./drivers/usb/storage/usual-tables.o

$ size (x86-64 defconfig post)
   text	   data	    bss	    dec	    hex	filename
  22809	    420	    480	  23709	   5c9d	drivers/usb/storage/usb.o
  10551	      0	      0	  10551	   2937	drivers/usb/storage/usual-tables.o

Signed-off-by: Joe Perches <joe@perches.com>
---

compile tested only

 drivers/usb/storage/usb.c          | 10 +++++-----
 drivers/usb/storage/usb.h          |  5 +++--
 drivers/usb/storage/usual-tables.c |  6 +++---
 include/linux/usb_usual.h          |  2 +-
 4 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index 9a79cd..94a6472 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -121,12 +121,12 @@ MODULE_PARM_DESC(quirks, "supplemental list of
device IDs and their quirks");
 	.initFunction = init_function,	\
 }
 
-static struct us_unusual_dev us_unusual_dev_list[] = {
+static const struct us_unusual_dev us_unusual_dev_list[] = {
 #	include "unusual_devs.h"
 	{ }		/* Terminating entry */
 };
 
-static struct us_unusual_dev for_dynamic_ids =
+static const struct us_unusual_dev for_dynamic_ids =
 		USUAL_DEV(USB_SC_SCSI, USB_PR_BULK);
 
 #undef UNUSUAL_DEV
@@ -583,7 +583,7 @@ EXPORT_SYMBOL_GPL(usb_stor_adjust_quirks);
 
 /* Get the unusual_devs entries and the string descriptors */
 static int get_device_info(struct us_data *us, const struct
usb_device_id *id,
-		struct us_unusual_dev *unusual_dev)
+		const struct us_unusual_dev *unusual_dev)
 {
 	struct usb_device *dev = us->pusb_dev;
 	struct usb_interface_descriptor *idesc =
@@ -933,7 +933,7 @@ static unsigned int usb_stor_sg_tablesize(struct
usb_interface *intf)
 int usb_stor_probe1(struct us_data **pus,
 		struct usb_interface *intf,
 		const struct usb_device_id *id,
-		struct us_unusual_dev *unusual_dev,
+		const struct us_unusual_dev *unusual_dev,
 		struct scsi_host_template *sht)
 {
 	struct Scsi_Host *host;
@@ -1092,7 +1092,7 @@ static struct scsi_host_template
usb_stor_host_template;
 static int storage_probe(struct usb_interface *intf,
 			 const struct usb_device_id *id)
 {
-	struct us_unusual_dev *unusual_dev;
+	const struct us_unusual_dev *unusual_dev;
 	struct us_data *us;
 	int result;
 	int size;
diff --git a/drivers/usb/storage/usb.h b/drivers/usb/storage/usb.h
index 85052c..5850d62 100644
--- a/drivers/usb/storage/usb.h
+++ b/drivers/usb/storage/usb.h
@@ -93,7 +93,8 @@ struct us_data {
 	struct mutex		dev_mutex;	 /* protect pusb_dev */
 	struct usb_device	*pusb_dev;	 /* this usb_device */
 	struct usb_interface	*pusb_intf;	 /* this interface */
-	struct us_unusual_dev   *unusual_dev;	 /* device-filter
entry     */
+	const struct us_unusual_dev   *unusual_dev;
+						/* device-filter
entry     */
 	unsigned long		fflags;		 /* fixed flags from
filter */
 	unsigned long		dflags;		 /* dynamic atomic
bitflags */
 	unsigned int		send_bulk_pipe;	 /* cached pipe values
*/
@@ -185,7 +186,7 @@ extern int usb_stor_post_reset(struct usb_interface
*iface);
 extern int usb_stor_probe1(struct us_data **pus,
 		struct usb_interface *intf,
 		const struct usb_device_id *id,
-		struct us_unusual_dev *unusual_dev,
+		const struct us_unusual_dev *unusual_dev,
 		struct scsi_host_template *sht);
 extern int usb_stor_probe2(struct us_data *us);
 extern void usb_stor_disconnect(struct usb_interface *intf);
diff --git a/drivers/usb/storage/usual-tables.c
b/drivers/usb/storage/usual-tables.c
index cfd12e5..529512 100644
--- a/drivers/usb/storage/usual-tables.c
+++ b/drivers/usb/storage/usual-tables.c
@@ -40,7 +40,7 @@
 	.driver_info = (flags) \
 }
 
-struct usb_device_id usb_storage_usb_ids[] = {
+const struct usb_device_id usb_storage_usb_ids[] = {
 #	include "unusual_devs.h"
 	{ }		/* Terminating entry */
 };
@@ -68,7 +68,7 @@ struct ignore_entry {
 	.bcdmax = bcdDeviceMax,		\
 }
 
-static struct ignore_entry ignore_ids[] = {
+static const struct ignore_entry ignore_ids[] = {
 #	include "unusual_alauda.h"
 #	include "unusual_cypress.h"
 #	include "unusual_datafab.h"
@@ -92,7 +92,7 @@ int usb_usual_ignore_device(struct usb_interface
*intf)
 {
 	struct usb_device *udev;
 	unsigned vid, pid, bcd;
-	struct ignore_entry *p;
+	const struct ignore_entry *p;
 
 	udev = interface_to_usbdev(intf);
 	vid = le16_to_cpu(udev->descriptor.idVendor);
diff --git a/include/linux/usb_usual.h b/include/linux/usb_usual.h
index 000a595..4a19ac3 100644
--- a/include/linux/usb_usual.h
+++ b/include/linux/usb_usual.h
@@ -92,6 +92,6 @@ enum { US_DO_ALL_FLAGS };
 #include <linux/usb/storage.h>
 
 extern int usb_usual_ignore_device(struct usb_interface *intf);
-extern struct usb_device_id usb_storage_usb_ids[];
+extern const struct usb_device_id usb_storage_usb_ids[];
 
 #endif /* __LINUX_USB_USUAL_H */



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