[power] Fix swsusp with preempt and clean up.

In order to snapshot memory, interrupts must be disabled. However, in order
to write the saved image to disk, interrupts must be re-enabled and devices
resumed. Previously, both actions were called from swsusp_arch_suspend().

This patch separates those two actions has only the snapshotting routine 
called from swsusp_arch_suspend(). swsusp now handles it's own disabling of
interrupts only for the time required. This is now handled from swsusp_save()
and swsusp_write() now handles writing the image only (called with interrupts
enabled).

swsusp_save_image() was renamed to swsusp_suspend() (and the old incarnation
deleted since it was simply a wrapper).

2 files changed, 30 insertions, 40 deletions

diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index e7e40119d917..64a3130a5411 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -163,27 +163,27 @@ int pm_suspend_disk(void)
 
 	pr_debug("PM: snapshotting memory.\n");
 	in_suspend = 1;
-	local_irq_disable();
 	if ((error = swsusp_save()))
 		goto Done;
 
-	pr_debug("PM: writing image.\n");
+	if (in_suspend) {
+		pr_debug("PM: writing image.\n");
 
-	/*
-	 * FIXME: Leftover from swsusp. Are they necessary?
-	 */
-	mb();
-	barrier();
+		/*
+		 * FIXME: Leftover from swsusp. Are they necessary?
+		 */
+		mb();
+		barrier();
 
-	error = swsusp_write();
-	if (!error && in_suspend) {
-		error = power_down(pm_disk_mode);
-		pr_debug("PM: Power down failed.\n");
+		error = swsusp_write();
+		if (!error) {
+			error = power_down(pm_disk_mode);
+			pr_debug("PM: Power down failed.\n");
+		}
 	} else
 		pr_debug("PM: Image restored successfully.\n");
 	swsusp_free();
  Done:
-	local_irq_enable();
 	finish();
 	return error;
 }
@@ -217,7 +217,6 @@ static int pm_resume(void)
 
 	barrier();
 	mb();
-	local_irq_disable();
 
 	/* FIXME: The following (comment and mdelay()) are from swsusp.
 	 * Are they really necessary?
@@ -231,7 +230,6 @@ static int pm_resume(void)
 
 	pr_debug("PM: Restoring saved image.\n");
 	swsusp_restore();
-	local_irq_enable();
 	pr_debug("PM: Restore failed, recovering.n");
 	finish();
  Free:
diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index e9a1e97a2f2b..bb795b6dc537 100644
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -416,11 +416,12 @@ static suspend_pagedir_t *create_suspend_pagedir(int nr_copy_pages)
 }
 
 
-static int suspend_prepare_image(void)
+int swsusp_suspend(void)
 {
 	struct sysinfo i;
 	unsigned int nr_needed_pages = 0;
 
+	read_swapfiles();
 	drain_local_pages();
 
 	pagedir_nosave = NULL;
@@ -486,12 +487,10 @@ static int suspend_prepare_image(void)
 static int suspend_save_image(void)
 {
 	int error;
-	local_irq_enable();
 	device_resume();
 	lock_swapdevices();
 	error = write_suspend_image();
 	lock_swapdevices();
-	local_irq_disable();
 	return error;
 }
 
@@ -515,35 +514,17 @@ int swsusp_resume(void)
 	if (!resume) {
 		save_processor_state();
 		SAVE_REGISTERS
-		swsusp_suspend();
-		return;
+		return swsusp_suspend();
 	}
 	GO_TO_SWAPPER_PAGE_TABLES
 	COPY_PAGES_BACK
 	RESTORE_REGISTERS
 	restore_processor_state();
-	swsusp_resume();
+	return swsusp_resume();
 
  */
 
 
-int swsusp_suspend(void)
-{
-	int error;
-	read_swapfiles();
-	error = suspend_prepare_image();
-	if (!error)
-		error = suspend_save_image();
-	if (error) {
-		printk(KERN_EMERG "%sSuspend failed, trying to recover...\n",
-		       name_suspend);
-		barrier();
-		mb();
-		mdelay(1000);
-	}
-	return error;
-}
-
 /* More restore stuff */
 
 /* FIXME: Why not memcpy(to, from, 1<<pagedir_order*PAGE_SIZE)? */
@@ -870,11 +851,18 @@ static int __init read_suspend_image(void)
 
 int swsusp_save(void) 
 {
+	int error;
+
 #if defined (CONFIG_HIGHMEM) || defined (COFNIG_DISCONTIGMEM)
 	printk("swsusp is not supported with high- or discontig-mem.\n");
 	return -EPERM;
 #endif
-	return arch_prepare_suspend();
+	if ((error = arch_prepare_suspend()))
+		return error;
+	local_irq_disable();
+	error = swsusp_arch_suspend(0);
+	local_irq_enable();
+	return error;
 }
 
 
@@ -890,7 +878,7 @@ int swsusp_save(void)
 
 int swsusp_write(void)
 {
-	return swsusp_arch_suspend(0);
+	return suspend_save_image();
 }
 
 
@@ -933,7 +921,11 @@ int __init swsusp_read(void)
 
 int __init swsusp_restore(void)
 {
-	return swsusp_arch_suspend(1);
+	int error;
+	local_irq_disable();
+	error = swsusp_arch_suspend(1);
+	local_irq_enable();
+	return error;
 }