[PATCH AUTOSEL 5.16 36/52] PM: wakeup: simplify the output logic of pm_show_wakelocks()

[PATCH AUTOSEL 5.16 36/52] PM: wakeup: simplify the output logic of pm_show_wakelocks()

[Sasha Levin]

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit c9d967b2ce40d71e968eb839f36c936b8a9cf1ea ]

The buffer handling in pm_show_wakelocks() is tricky, and hopefully
correct.  Ensure it really is correct by using sysfs_emit_at() which
handles all of the tricky string handling logic in a PAGE_SIZE buffer
for us automatically as this is a sysfs file being read from.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/power/wakelock.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c
index 105df4dfc7839..52571dcad768b 100644
--- a/kernel/power/wakelock.c
+++ b/kernel/power/wakelock.c
@@ -39,23 +39,20 @@ ssize_t pm_show_wakelocks(char *buf, bool show_active)
 {
 	struct rb_node *node;
 	struct wakelock *wl;
-	char *str = buf;
-	char *end = buf + PAGE_SIZE;
+	int len = 0;
 
 	mutex_lock(&wakelocks_lock);
 
 	for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
 		wl = rb_entry(node, struct wakelock, node);
 		if (wl->ws->active == show_active)
-			str += scnprintf(str, end - str, "%s ", wl->name);
+			len += sysfs_emit_at(buf, len, "%s ", wl->name);
 	}
-	if (str > buf)
-		str--;
 
-	str += scnprintf(str, end - str, "\n");
+	len += sysfs_emit_at(buf, len, "\n");
 
 	mutex_unlock(&wakelocks_lock);
-	return (str - buf);
+	return len;
 }
 
 #if CONFIG_PM_WAKELOCKS_LIMIT > 0
-- 
2.34.1

[PATCH AUTOSEL 5.16 37/52] PM: hibernate: Remove register_nosave_region_late()

[Sasha Levin]

From: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>

[ Upstream commit 33569ef3c754a82010f266b7b938a66a3ccf90a4 ]

It is an unused wrapper forcing kmalloc allocation for registering
nosave regions. Also, rename __register_nosave_region() to
register_nosave_region() now that there is no need for disambiguation.

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/suspend.h | 11 +----------
 kernel/power/snapshot.c | 21 +++++++--------------
 2 files changed, 8 insertions(+), 24 deletions(-)

diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 8af13ba60c7e4..c1310c571d805 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -430,15 +430,7 @@ struct platform_hibernation_ops {
 
 #ifdef CONFIG_HIBERNATION
 /* kernel/power/snapshot.c */
-extern void __register_nosave_region(unsigned long b, unsigned long e, int km);
-static inline void __init register_nosave_region(unsigned long b, unsigned long e)
-{
-	__register_nosave_region(b, e, 0);
-}
-static inline void __init register_nosave_region_late(unsigned long b, unsigned long e)
-{
-	__register_nosave_region(b, e, 1);
-}
+extern void register_nosave_region(unsigned long b, unsigned long e);
 extern int swsusp_page_is_forbidden(struct page *);
 extern void swsusp_set_page_free(struct page *);
 extern void swsusp_unset_page_free(struct page *);
@@ -457,7 +449,6 @@ int pfn_is_nosave(unsigned long pfn);
 int hibernate_quiet_exec(int (*func)(void *data), void *data);
 #else /* CONFIG_HIBERNATION */
 static inline void register_nosave_region(unsigned long b, unsigned long e) {}
-static inline void register_nosave_region_late(unsigned long b, unsigned long e) {}
 static inline int swsusp_page_is_forbidden(struct page *p) { return 0; }
 static inline void swsusp_set_page_free(struct page *p) {}
 static inline void swsusp_unset_page_free(struct page *p) {}
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index f7a9860782135..330d499376924 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -978,8 +978,7 @@ static void memory_bm_recycle(struct memory_bitmap *bm)
  * Register a range of page frames the contents of which should not be saved
  * during hibernation (to be used in the early initialization code).
  */
-void __init __register_nosave_region(unsigned long start_pfn,
-				     unsigned long end_pfn, int use_kmalloc)
+void __init register_nosave_region(unsigned long start_pfn, unsigned long end_pfn)
 {
 	struct nosave_region *region;
 
@@ -995,18 +994,12 @@ void __init __register_nosave_region(unsigned long start_pfn,
 			goto Report;
 		}
 	}
-	if (use_kmalloc) {
-		/* During init, this shouldn't fail */
-		region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL);
-		BUG_ON(!region);
-	} else {
-		/* This allocation cannot fail */
-		region = memblock_alloc(sizeof(struct nosave_region),
-					SMP_CACHE_BYTES);
-		if (!region)
-			panic("%s: Failed to allocate %zu bytes\n", __func__,
-			      sizeof(struct nosave_region));
-	}
+	/* This allocation cannot fail */
+	region = memblock_alloc(sizeof(struct nosave_region),
+				SMP_CACHE_BYTES);
+	if (!region)
+		panic("%s: Failed to allocate %zu bytes\n", __func__,
+		      sizeof(struct nosave_region));
 	region->start_pfn = start_pfn;
 	region->end_pfn = end_pfn;
 	list_add_tail(&region->list, &nosave_regions);
-- 
2.34.1

Re: [PATCH AUTOSEL 5.16 36/52] PM: wakeup: simplify the output logic of pm_show_wakelocks()

[Greg Kroah-Hartman]

On Thu, Feb 03, 2022 at 03:29:30PM -0500, Sasha Levin wrote:
> From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> [ Upstream commit c9d967b2ce40d71e968eb839f36c936b8a9cf1ea ]
> 
> The buffer handling in pm_show_wakelocks() is tricky, and hopefully
> correct.  Ensure it really is correct by using sysfs_emit_at() which
> handles all of the tricky string handling logic in a PAGE_SIZE buffer
> for us automatically as this is a sysfs file being read from.
> 
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Lee Jones <lee.jones@linaro.org>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  kernel/power/wakelock.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)

This is already in a stable release, so no need to add it again.

thanks,

greg k-h