[PATCH v3 2/2] pm: add more logging on hibernation failure

[Luigi Semenzato <semenzato@google.com>]

Hibernation fails when the kernel cannot allocate enough memory
to copy all pages in use.  This patch ensures that the failure
reason is clearly logged, and clearly attributable to the
hibernation module.

Signed-off-by: Luigi Semenzato <semenzato@google.com>
---
 kernel/power/hibernate.c | 23 ++++++++++++-----------
 kernel/power/snapshot.c  | 24 +++++++++++++++---------
 2 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 3c0a5a8170b0..6dbeedb7354c 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -9,7 +9,7 @@
  * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com>
  */
 
-#define pr_fmt(fmt) "PM: " fmt
+#define pr_fmt(fmt) "PM: hibernation: " fmt
 
 #include <linux/export.h>
 #include <linux/suspend.h>
@@ -106,7 +106,7 @@ EXPORT_SYMBOL(system_entering_hibernation);
 #ifdef CONFIG_PM_DEBUG
 static void hibernation_debug_sleep(void)
 {
-	pr_info("hibernation debug: Waiting for 5 seconds.\n");
+	pr_info("debug: Waiting for 5 seconds.\n");
 	mdelay(5000);
 }
 
@@ -277,7 +277,7 @@ static int create_image(int platform_mode)
 
 	error = dpm_suspend_end(PMSG_FREEZE);
 	if (error) {
-		pr_err("Some devices failed to power down, aborting hibernation\n");
+		pr_err("Some devices failed to power down, aborting\n");
 		return error;
 	}
 
@@ -295,7 +295,7 @@ static int create_image(int platform_mode)
 
 	error = syscore_suspend();
 	if (error) {
-		pr_err("Some system devices failed to power down, aborting hibernation\n");
+		pr_err("Some system devices failed to power down, aborting\n");
 		goto Enable_irqs;
 	}
 
@@ -310,7 +310,7 @@ static int create_image(int platform_mode)
 	restore_processor_state();
 	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 	if (error)
-		pr_err("Error %d creating hibernation image\n", error);
+		pr_err("Error %d creating image\n", error);
 
 	if (!in_suspend) {
 		events_check_enabled = false;
@@ -680,7 +680,7 @@ static int load_image_and_restore(void)
 	if (!error)
 		hibernation_restore(flags & SF_PLATFORM_MODE);
 
-	pr_err("Failed to load hibernation image, recovering.\n");
+	pr_err("Failed to load image, recovering.\n");
 	swsusp_free();
 	free_basic_memory_bitmaps();
  Unlock:
@@ -743,7 +743,7 @@ int hibernate(void)
 		else
 		        flags |= SF_CRC32_MODE;
 
-		pm_pr_dbg("Writing image.\n");
+		pm_pr_dbg("Writing hibernation image.\n");
 		error = swsusp_write(flags);
 		swsusp_free();
 		if (!error) {
@@ -755,7 +755,7 @@ int hibernate(void)
 		in_suspend = 0;
 		pm_restore_gfp_mask();
 	} else {
-		pm_pr_dbg("Image restored successfully.\n");
+		pm_pr_dbg("Hibernation image restored successfully.\n");
 	}
 
  Free_bitmaps:
@@ -894,7 +894,7 @@ static int software_resume(void)
 		goto Close_Finish;
 	}
 
-	pm_pr_dbg("Preparing processes for restore.\n");
+	pm_pr_dbg("Preparing processes for hibernation restore.\n");
 	error = freeze_processes();
 	if (error)
 		goto Close_Finish;
@@ -903,7 +903,7 @@ static int software_resume(void)
  Finish:
 	__pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
 	pm_restore_console();
-	pr_info("resume from hibernation failed (%d)\n", error);
+	pr_info("resume failed (%d)\n", error);
 	atomic_inc(&snapshot_device_available);
 	/* For success case, the suspend path will release the lock */
  Unlock:
@@ -1068,7 +1068,8 @@ static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
 	lock_system_sleep();
 	swsusp_resume_device = res;
 	unlock_system_sleep();
-	pm_pr_dbg("Configured resume from disk to %u\n", swsusp_resume_device);
+	pm_pr_dbg("Configured hibernation resume from disk to %u\n",
+		  swsusp_resume_device);
 	noresume = 0;
 	software_resume();
 	return n;
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 26b9168321e7..dcd1376e8fdf 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -8,7 +8,7 @@
  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
  */
 
-#define pr_fmt(fmt) "PM: " fmt
+#define pr_fmt(fmt) "PM: hibernation: " fmt
 
 #include <linux/version.h>
 #include <linux/module.h>
@@ -1705,16 +1705,20 @@ int hibernate_preallocate_memory(void)
 	ktime_t start, stop;
 	int error;
 
-	pr_info("Preallocating image memory... ");
+	pr_info("Preallocating image memory\n");
 	start = ktime_get();
 
 	error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
-	if (error)
+	if (error) {
+		pr_err("Cannot allocate original bitmap\n");
 		goto err_out;
+	}
 
 	error = memory_bm_create(&copy_bm, GFP_IMAGE, PG_ANY);
-	if (error)
+	if (error) {
+		pr_err("Cannot allocate copy bitmap\n");
 		goto err_out;
+	}
 
 	alloc_normal = 0;
 	alloc_highmem = 0;
@@ -1804,8 +1808,11 @@ int hibernate_preallocate_memory(void)
 		alloc -= pages;
 		pages += pages_highmem;
 		pages_highmem = preallocate_image_highmem(alloc);
-		if (pages_highmem < alloc)
+		if (pages_highmem < alloc) {
+			pr_err("Image allocation is %lu pages short\n",
+				alloc - pages_highmem);
 			goto err_out;
+		}
 		pages += pages_highmem;
 		/*
 		 * size is the desired number of saveable pages to leave in
@@ -1836,13 +1843,12 @@ int hibernate_preallocate_memory(void)
 
  out:
 	stop = ktime_get();
-	pr_cont("done (allocated %lu pages)\n", pages);
+	pr_info("Allocated %lu pages for shapshot\n", pages);
 	swsusp_show_speed(start, stop, pages, "Allocated");
 
 	return 0;
 
  err_out:
-	pr_cont("\n");
 	swsusp_free();
 	return -ENOMEM;
 }
@@ -1976,7 +1982,7 @@ asmlinkage __visible int swsusp_save(void)
 {
 	unsigned int nr_pages, nr_highmem;
 
-	pr_info("Creating hibernation image:\n");
+	pr_info("Creating image:\n");
 
 	drain_local_pages(NULL);
 	nr_pages = count_data_pages();
@@ -2010,7 +2016,7 @@ asmlinkage __visible int swsusp_save(void)
 	nr_copy_pages = nr_pages;
 	nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
 
-	pr_info("Hibernation image created (%d pages copied)\n", nr_pages);
+	pr_info("Image created (%d pages copied)\n", nr_pages);
 
 	return 0;
 }
-- 
2.24.1.735.g03f4e72817-goog