[PATCH v6 10/10] mm/memory_hotplug: Cleanup __remove_pages()

[David Hildenbrand]

Let's drop the basically unused section stuff and simplify.

Also, let's use a shorter variant to calculate the number of pages to
the next section boundary.

Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Oscar Salvador <osalva...@suse.de>
Cc: Michal Hocko <mho...@suse.com>
Cc: Pavel Tatashin <pasha.tatas...@soleen.com>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Wei Yang <richardw.y...@linux.intel.com>
Signed-off-by: David Hildenbrand <da...@redhat.com>
---
 mm/memory_hotplug.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 843481bd507d..2275240cfa10 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -490,25 +490,20 @@ static void __remove_section(unsigned long pfn, unsigned 
long nr_pages,
 void __remove_pages(unsigned long pfn, unsigned long nr_pages,
                    struct vmem_altmap *altmap)
 {
+       const unsigned long end_pfn = pfn + nr_pages;
+       unsigned long cur_nr_pages;
        unsigned long map_offset = 0;
-       unsigned long nr, start_sec, end_sec;
 
        map_offset = vmem_altmap_offset(altmap);
 
        if (check_pfn_span(pfn, nr_pages, "remove"))
                return;
 
-       start_sec = pfn_to_section_nr(pfn);
-       end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
-       for (nr = start_sec; nr <= end_sec; nr++) {
-               unsigned long pfns;
-
+       for (; pfn < end_pfn; pfn += cur_nr_pages) {
                cond_resched();
-               pfns = min(nr_pages, PAGES_PER_SECTION
-                               - (pfn & ~PAGE_SECTION_MASK));
-               __remove_section(pfn, pfns, map_offset, altmap);
-               pfn += pfns;
-               nr_pages -= pfns;
+               /* Select all remaining pages up to the next section boundary */
+               cur_nr_pages = min(end_pfn - pfn, -(pfn | PAGE_SECTION_MASK));
+               __remove_section(pfn, cur_nr_pages, map_offset, altmap);
                map_offset = 0;
        }
 }
-- 
2.21.0