[PATCH] swsusp: rework swsusp_suspend

This patch makes only the functions in swsusp.c call functions in snapshot.c
and not both ways.  It also moves the check for available swap out of
swsusp_suspend() which is necessary for separating the swap-handling functions
in swsusp from the core code.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/power/power.h

@@ -65,10 +65,8 @@ extern suspend_pagedir_t *pagedir_save;
 extern asmlinkage int swsusp_arch_suspend(void);
 extern asmlinkage int swsusp_arch_resume(void);
 
-extern int restore_highmem(void);
 extern void free_pagedir(struct pbe *pblist);
 extern struct pbe *alloc_pagedir(unsigned nr_pages, gfp_t gfp_mask, int safe_needed);
 extern void create_pbe_list(struct pbe *pblist, unsigned nr_pages);
 extern void swsusp_free(void);
 extern int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed);
-extern int enough_swap(unsigned nr_pages);

kernel/power/snapshot.c

@@ -88,8 +88,7 @@ static int save_highmem_zone(struct zone *zone)
 	return 0;
 }
 
-
-static int save_highmem(void)
+int save_highmem(void)
 {
 	struct zone *zone;
 	int res = 0;
@@ -120,11 +119,7 @@ int restore_highmem(void)
 	}
 	return 0;
 }
-#else
-static int save_highmem(void) { return 0; }
-int restore_highmem(void) { return 0; }
-#endif /* CONFIG_HIGHMEM */
-
+#endif
 
 static int pfn_is_nosave(unsigned long pfn)
 {
@@ -416,11 +411,6 @@ asmlinkage int swsusp_save(void)
 	unsigned int nr_pages;
 
 	pr_debug("swsusp: critical section: \n");
-	if (save_highmem()) {
-		printk(KERN_CRIT "swsusp: Not enough free pages for highmem\n");
-		restore_highmem();
-		return -ENOMEM;
-	}
 
 	drain_local_pages();
 	nr_pages = count_data_pages();
@@ -440,11 +430,6 @@ asmlinkage int swsusp_save(void)
 		return -ENOMEM;
 	}
 
-	if (!enough_swap(nr_pages)) {
-		printk(KERN_ERR "swsusp: Not enough free swap\n");
-		return -ENOSPC;
-	}
-
 	pagedir_nosave = swsusp_alloc(nr_pages);
 	if (!pagedir_nosave)
 		return -ENOMEM;

kernel/power/swsusp.c

@@ -73,6 +73,14 @@
 
 #include "power.h"
 
+#ifdef CONFIG_HIGHMEM
+int save_highmem(void);
+int restore_highmem(void);
+#else
+static int save_highmem(void) { return 0; }
+static int restore_highmem(void) { return 0; }
+#endif
+
 #define CIPHER "aes"
 #define MAXKEY 32
 #define MAXIV  32
@@ -499,6 +507,26 @@ static int write_pagedir(void)
 	return error;
 }
 
+/**
+ *	enough_swap - Make sure we have enough swap to save the image.
+ *
+ *	Returns TRUE or FALSE after checking the total amount of swap
+ *	space avaiable.
+ *
+ *	FIXME: si_swapinfo(&i) returns all swap devices information.
+ *	We should only consider resume_device.
+ */
+
+static int enough_swap(unsigned int nr_pages)
+{
+	struct sysinfo i;
+
+	si_swapinfo(&i);
+	pr_debug("swsusp: available swap: %lu pages\n", i.freeswap);
+	return i.freeswap > (nr_pages + PAGES_FOR_IO +
+		(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
+}
+
 /**
  *	write_suspend_image - Write entire image and metadata.
  *
@@ -507,6 +535,11 @@ static int write_suspend_image(void)
 {
 	int error;
 
+	if (!enough_swap(nr_copy_pages)) {
+		printk(KERN_ERR "swsusp: Not enough free swap\n");
+		return -ENOSPC;
+	}
+
 	init_header();
 	if ((error = data_write()))
 		goto FreeData;
@@ -526,27 +559,6 @@ static int write_suspend_image(void)
 	goto Done;
 }
 
-/**
- *	enough_swap - Make sure we have enough swap to save the image.
- *
- *	Returns TRUE or FALSE after checking the total amount of swap
- *	space avaiable.
- *
- *	FIXME: si_swapinfo(&i) returns all swap devices information.
- *	We should only consider resume_device.
- */
-
-int enough_swap(unsigned int nr_pages)
-{
-	struct sysinfo i;
-
-	si_swapinfo(&i);
-	pr_debug("swsusp: available swap: %lu pages\n", i.freeswap);
-	return i.freeswap > (nr_pages + PAGES_FOR_IO +
-		(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
-}
-
-
 /* It is important _NOT_ to umount filesystems at this point. We want
  * them synced (in case something goes wrong) but we DO not want to mark
  * filesystem clean: it is not. (And it does not matter, if we resume
@@ -556,12 +568,15 @@ int swsusp_write(void)
 {
 	int error;
 
+	if ((error = swsusp_swap_check())) {
+		printk(KERN_ERR "swsusp: cannot find swap device, try swapon -a.\n");
+		return error;
+	}
 	lock_swapdevices();
 	error = write_suspend_image();
 	/* This will unlock ignored swap devices since writing is finished */
 	lock_swapdevices();
 	return error;
-
 }
 
 
@@ -569,6 +584,7 @@ int swsusp_write(void)
 int swsusp_suspend(void)
 {
 	int error;
+
 	if ((error = arch_prepare_suspend()))
 		return error;
 	local_irq_disable();
@@ -580,15 +596,12 @@ int swsusp_suspend(void)
 	 */
 	if ((error = device_power_down(PMSG_FREEZE))) {
 		printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
-		local_irq_enable();
-		return error;
+		goto Enable_irqs;
 	}
 
-	if ((error = swsusp_swap_check())) {
-		printk(KERN_ERR "swsusp: cannot find swap device, try swapon -a.\n");
-		device_power_up();
-		local_irq_enable();
-		return error;
+	if ((error = save_highmem())) {
+		printk(KERN_ERR "swsusp: Not enough free pages for highmem\n");
+		goto Restore_highmem;
 	}
 
 	save_processor_state();
@@ -596,8 +609,10 @@ int swsusp_suspend(void)
 		printk(KERN_ERR "Error %d suspending\n", error);
 	/* Restore control flow magically appears here */
 	restore_processor_state();
+Restore_highmem:
 	restore_highmem();
 	device_power_up();
+Enable_irqs:
 	local_irq_enable();
 	return error;
 }
@@ -804,7 +819,7 @@ static int check_sig(void)
 		 * Reset swap signature now.
 		 */
 		error = bio_write_page(0, &swsusp_header);
-	} else { 
+	} else {
 		return -EINVAL;
 	}
 	if (!error)