[PATCH v1 3/4] mm/memory_hotplug: Make __remove_section() never fail

From: David Hildenbrand <david@redhat.com>
To: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org,
	David Hildenbrand <david@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Oscar Salvador <osalvador@suse.de>,
	Michal Hocko <mhocko@suse.com>,
	Pavel Tatashin <pasha.tatashin@soleen.com>, Qian Cai <cai@lca.pw>,
	Wei Yang <richard.weiyang@gmail.com>,
	Arun KS <arunks@codeaurora.org>,
	Mathieu Malaterre <malat@debian.org>
Subject: [PATCH v1 3/4] mm/memory_hotplug: Make __remove_section() never fail
Date: Tue,  9 Apr 2019 12:01:47 +0200	[thread overview]
Message-ID: <20190409100148.24703-4-david@redhat.com> (raw)
In-Reply-To: <20190409100148.24703-1-david@redhat.com>

Let's just warn in case a section is not valid instead of failing to
remove somewhere in the middle of the process, returning an error that
will be mostly ignored by callers.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Mathieu Malaterre <malat@debian.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 mm/memory_hotplug.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index b0cb05748f99..17a60281c36f 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -517,15 +517,15 @@ static void __remove_zone(struct zone *zone, unsigned long start_pfn)
 	pgdat_resize_unlock(zone->zone_pgdat, &flags);
 }
 
-static int __remove_section(struct zone *zone, struct mem_section *ms,
-		unsigned long map_offset, struct vmem_altmap *altmap)
+static void __remove_section(struct zone *zone, struct mem_section *ms,
+			     unsigned long map_offset,
+			     struct vmem_altmap *altmap)
 {
 	unsigned long start_pfn;
 	int scn_nr;
-	int ret = -EINVAL;
 
-	if (!valid_section(ms))
-		return ret;
+	if (WARN_ON_ONCE(!valid_section(ms)))
+		return;
 
 	unregister_memory_section(ms);
 
@@ -534,7 +534,6 @@ static int __remove_section(struct zone *zone, struct mem_section *ms,
 	__remove_zone(zone, start_pfn);
 
 	sparse_remove_one_section(zone, ms, map_offset, altmap);
-	return 0;
 }
 
 /**
@@ -554,7 +553,7 @@ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
 {
 	unsigned long i;
 	unsigned long map_offset = 0;
-	int sections_to_remove, ret = 0;
+	int sections_to_remove;
 
 	/* In the ZONE_DEVICE case device driver owns the memory region */
 	if (is_dev_zone(zone)) {
@@ -575,16 +574,13 @@ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
 		unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
 
 		cond_resched();
-		ret = __remove_section(zone, __pfn_to_section(pfn), map_offset,
-				altmap);
+		__remove_section(zone, __pfn_to_section(pfn), map_offset,
+				 altmap);
 		map_offset = 0;
-		if (ret)
-			break;
 	}
 
 	set_zone_contiguous(zone);
-
-	return ret;
+	return 0;
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
-- 
2.17.2

