mm/sparse: remove sparse_decode_mem_map()

section_deactivate() applies to CONFIG_SPARSEMEM_VMEMMAP only.  So we can
just use pfn_to_page() (after making sure we have the start PFN of the
section), and remove sparse_decode_mem_map().

Link: https://lkml.kernel.org/r/20260320-sparsemem_cleanups-v2-9-096addc8800d@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index e77ef3d7ff7334cab1d3caf50ed36069bdd342f9..815e908c4135b1f34aeecab5174d49e77d9e1d18 100644 (file)
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -308,8 +308,6 @@ extern int sparse_add_section(int nid, unsigned long pfn,
                struct dev_pagemap *pgmap);
 extern void sparse_remove_section(unsigned long pfn, unsigned long nr_pages,
                                  struct vmem_altmap *altmap);
-extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
-                                         unsigned long pnum);
 extern struct zone *zone_for_pfn_range(enum mmop online_type,
                int nid, struct memory_group *group, unsigned long start_pfn,
                unsigned long nr_pages);

diff --git a/mm/sparse.c b/mm/sparse.c
index 875f718a4c79771f97123a50877751ad8e193799..b5825c9ee2f2b0bd0ff88e69a50ba4c524ff0cf6 100644 (file)
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -274,18 +274,6 @@ static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long p
        return coded_mem_map;
 }
 
-#ifdef CONFIG_MEMORY_HOTPLUG
-/*
- * Decode mem_map from the coded memmap
- */
-struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
-{
-       /* mask off the extra low bits of information */
-       coded_mem_map &= SECTION_MAP_MASK;
-       return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
-}
-#endif /* CONFIG_MEMORY_HOTPLUG */
-
 static void __meminit sparse_init_one_section(struct mem_section *ms,
                unsigned long pnum, struct page *mem_map,
                struct mem_section_usage *usage, unsigned long flags)
@@ -754,8 +742,6 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
 
        empty = is_subsection_map_empty(ms);
        if (empty) {
-               unsigned long section_nr = pfn_to_section_nr(pfn);
-
                /*
                 * Mark the section invalid so that valid_section()
                 * return false. This prevents code from dereferencing
@@ -774,7 +760,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
                        kfree_rcu(ms->usage, rcu);
                        WRITE_ONCE(ms->usage, NULL);
                }
-               memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
+               memmap = pfn_to_page(SECTION_ALIGN_DOWN(pfn));
        }
 
        /*