Greg KH wrote:
> On Mon, Jun 22, 2009 at 11:32:22AM -0500, Jason Wessel wrote:
>
>> There is no need to have external function calls for the sysrq
>> functions. The compiler can inline the sysrq calls such that they are
>> entirely a NOP if CONFIG_MAGIC_SYSRQ is not set.
>>
>> Signed-off-by: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
>> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
>>
>
> This now doesn't seem needed in Linus's tree due to Alan's changes,
> right?
>
> I've dropped it, if it's still needed, please redo and send it to me.
>
>
I re-spun the patch. It is not necessarily "required", but I think it
is a good practice to optimize the usb serial code in the same manner as
the rs232 uart driver code, and of course cutting out two extra kernel
exports and a level of extra function calls.
If you would prefer to keep it the way it is, let me know, because I
have a change set that stacks on top of this, for processing the sysrq
with a tasklet.
Thanks,
Jason.
From: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
Date: Wed, 17 Jun 2009 14:00:06 -0500
Subject: [PATCH] usb-serial: optimize sysrq function calls
There is no need to have external function calls for the sysrq
functions. The compiler can inline the sysrq calls such that they are
entirely a NOP if CONFIG_MAGIC_SYSRQ is not set.
Signed-off-by: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
---
drivers/usb/serial/generic.c | 26 --------------------------
include/linux/usb/serial.h | 34 +++++++++++++++++++++++++++++-----
2 files changed, 29 insertions(+), 31 deletions(-)
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -534,32 +534,6 @@ void usb_serial_generic_unthrottle(struc
}
}
-int usb_serial_handle_sysrq_char(struct tty_struct *tty,
- struct usb_serial_port *port, unsigned int ch)
-{
- if (port->sysrq && port->console) {
- if (ch && time_before(jiffies, port->sysrq)) {
- handle_sysrq(ch, tty);
- port->sysrq = 0;
- return 1;
- }
- port->sysrq = 0;
- }
- return 0;
-}
-EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
-
-int usb_serial_handle_break(struct usb_serial_port *port)
-{
- if (!port->sysrq) {
- port->sysrq = jiffies + HZ*5;
- return 1;
- }
- port->sysrq = 0;
- return 0;
-}
-EXPORT_SYMBOL_GPL(usb_serial_handle_break);
-
void usb_serial_generic_disconnect(struct usb_serial *serial)
{
int i;
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -317,11 +317,6 @@ extern int usb_serial_generic_register(i
extern void usb_serial_generic_deregister(void);
extern void usb_serial_generic_resubmit_read_urb(struct usb_serial_port *port,
gfp_t mem_flags);
-extern int usb_serial_handle_sysrq_char(struct tty_struct *tty,
- struct usb_serial_port *port,
- unsigned int ch);
-extern int usb_serial_handle_break(struct usb_serial_port *port);
-
extern int usb_serial_bus_register(struct usb_serial_driver *device);
extern void usb_serial_bus_deregister(struct usb_serial_driver *device);
@@ -330,6 +325,35 @@ extern struct usb_serial_driver usb_seri
extern struct bus_type usb_serial_bus_type;
extern struct tty_driver *usb_serial_tty_driver;
+static inline int usb_serial_handle_sysrq_char(struct tty_struct *tty,
+ struct usb_serial_port *port,
+ unsigned int ch)
+{
+#ifdef CONFIG_MAGIC_SYSRQ
+ if (port->sysrq && port->console) {
+ if (ch && time_before(jiffies, port->sysrq)) {
+ handle_sysrq(ch, tty);
+ port->sysrq = 0;
+ return 1;
+ }
+ port->sysrq = 0;
+ }
+#endif /* CONFIG_MAGIC_SYSRQ */
+ return 0;
+}
+
+static inline int usb_serial_handle_break(struct usb_serial_port *port)
+{
+#ifdef CONFIG_MAGIC_SYSRQ
+ if (!port->sysrq) {
+ port->sysrq = jiffies + HZ*5;
+ return 1;
+ }
+ port->sysrq = 0;
+#endif /* CONFIG_MAGIC_SYSRQ */
+ return 0;
+}
+
static inline void usb_serial_debug_data(int debug,
struct device *dev,
const char *function, int size,
