linux-kernel - Re: [PATCH 2/3] PM / Sleep: Make enter_state() in kernel/power/suspend.c static

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Date:	Sun, 12 Feb 2012 22:24:14 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
Cc:	Linux PM list <linux-pm@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Randy Dunlap <rdunlap@...otime.net>
Subject: Re: [PATCH 2/3] PM / Sleep: Make enter_state() in kernel/power/suspend.c static

On Sunday, February 12, 2012, Srivatsa S. Bhat wrote:
> On 02/12/2012 04:34 AM, Rafael J. Wysocki wrote:
> 
> > From: Rafael J. Wysocki <rjw@...k.pl>
> > 
> > The enter_state() function in kernel/power/suspend.c should be
> > static and state_store() in kernel/power/suspend.c should call
> > pm_suspend() instead of it, so make that happen (which also reduces
> > code duplication related to suspend statistics).
> > 
> > Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
> > ---
> >  kernel/power/main.c    |    6 +-----
> >  kernel/power/power.h   |    2 --
> >  kernel/power/suspend.c |    2 +-
> >  3 files changed, 2 insertions(+), 8 deletions(-)
> > 
> > Index: linux/kernel/power/main.c
> > ===================================================================
> > --- linux.orig/kernel/power/main.c
> > +++ linux/kernel/power/main.c
> > @@ -292,11 +292,7 @@ static ssize_t state_store(struct kobjec
> >  #ifdef CONFIG_SUSPEND
> >  	for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
> >  		if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
> > -			break;
> > -	}
> > -	if (state < PM_SUSPEND_MAX && *s) {
> > -		error = enter_state(state);
> > -		suspend_stats_update(error);
> > +			error = pm_suspend(state);
> 
> 
> This code will not stop after calling pm_suspend(). It will try more iterations
> in the for loop right?

Well, only one string in pm_states[] can be matched at a time, but I agree that
it doesn't make sense to continue the loop after we've found a match.

> We can probably keep the 'for' loop as it is, and just replace the 'if' block
> following the 'for' loop by: error = pm_suspend(state);

I think the patch below is correct.

Thanks,
Rafael

---
From: Rafael J. Wysocki <rjw@...k.pl>
Subject: PM / Sleep: Make enter_state() in kernel/power/suspend.c static

The enter_state() function in kernel/power/suspend.c should be
static and state_store() in kernel/power/suspend.c should call
pm_suspend() instead of it, so make that happen (which also reduces
code duplication related to suspend statistics).

Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
---
 kernel/power/main.c    |    8 +++-----
 kernel/power/power.h   |    2 --
 kernel/power/suspend.c |    2 +-
 3 files changed, 4 insertions(+), 8 deletions(-)

Index: linux/kernel/power/main.c
===================================================================
--- linux.orig/kernel/power/main.c
+++ linux/kernel/power/main.c
@@ -291,12 +291,10 @@ static ssize_t state_store(struct kobjec
 
 #ifdef CONFIG_SUSPEND
 	for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
-		if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
+		if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
+			error = pm_suspend(state);
 			break;
-	}
-	if (state < PM_SUSPEND_MAX && *s) {
-		error = enter_state(state);
-		suspend_stats_update(error);
+		}
 	}
 #endif
 
Index: linux/kernel/power/power.h
===================================================================
--- linux.orig/kernel/power/power.h
+++ linux/kernel/power/power.h
@@ -177,13 +177,11 @@ extern const char *const pm_states[];
 
 extern bool valid_state(suspend_state_t state);
 extern int suspend_devices_and_enter(suspend_state_t state);
-extern int enter_state(suspend_state_t state);
 #else /* !CONFIG_SUSPEND */
 static inline int suspend_devices_and_enter(suspend_state_t state)
 {
 	return -ENOSYS;
 }
-static inline int enter_state(suspend_state_t state) { return -ENOSYS; }
 static inline bool valid_state(suspend_state_t state) { return false; }
 #endif /* !CONFIG_SUSPEND */
 
Index: linux/kernel/power/suspend.c
===================================================================
--- linux.orig/kernel/power/suspend.c
+++ linux/kernel/power/suspend.c
@@ -272,7 +272,7 @@ static void suspend_finish(void)
  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
  * system enter the given sleep state and clean up after wakeup.
  */
-int enter_state(suspend_state_t state)
+static int enter_state(suspend_state_t state)
 {
 	int error;
 
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