seems there are couples archs can not do cmpxchg1
So update the patch here. And it's easy to fix if more arch issue find here.
>From cdf98ae7b5e83bb7210c927d4749f62fee4ed115 Mon Sep 17 00:00:00 2001
From: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Date: Mon, 31 Aug 2020 15:41:20 +0800
Subject: [PATCH v4 3/3] mm/pageblock: work around multiple arch's cmpxchg
support issue
Armv6, sh2, sparc32 and xtensa can not do cmpxchg1, so we have to use
cmpxchg4 on it.
arm-linux-gnueabi-ld: mm/page_alloc.o: in function `set_pfnblock_flags_mask':
(.text+0x32b4): undefined reference to `__bad_cmpxchg'
arm-linux-gnueabi-ld: (.text+0x32e0): undefined reference to `__bad_cmpxchg'
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
---
include/linux/mmzone.h | 20 +++++++++++++++++---
mm/page_alloc.c | 24 ++++++++++++------------
2 files changed, 29 insertions(+), 15 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index be676e659fb7..364b29ed99b3 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -406,6 +406,20 @@ enum zone_type {
#ifndef __GENERATING_BOUNDS_H
+/*
+ * cmpxchg only support 32-bits operands on the following archs ARMv6, SPARC32
+ * sh2, XTENSA.
+ */
+#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_SH2) || \
+ defined(CONFIG_SPARC32) || defined(CONFIG_XTENSA)
+
+#define BITS_PER_FLAGS BITS_PER_LONG
+typedef unsigned long pageblockflags_t;
+#else
+#define BITS_PER_FLAGS BITS_PER_BYTE
+typedef unsigned char pageblockflags_t;
+#endif
+
struct zone {
/* Read-mostly fields */
@@ -437,7 +451,7 @@ struct zone {
* Flags for a pageblock_nr_pages block. See pageblock-flags.h.
* In SPARSEMEM, this map is stored in struct mem_section
*/
- unsigned char *pageblock_flags;
+ pageblockflags_t *pageblock_flags;
#endif /* CONFIG_SPARSEMEM */
/* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
@@ -1159,7 +1173,7 @@ struct mem_section_usage {
DECLARE_BITMAP(subsection_map, SUBSECTIONS_PER_SECTION);
#endif
/* See declaration of similar field in struct zone */
- unsigned char pageblock_flags[0];
+ pageblockflags_t pageblock_flags[0];
};
void subsection_map_init(unsigned long pfn, unsigned long nr_pages);
@@ -1212,7 +1226,7 @@ struct mem_section {
extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
#endif
-static inline unsigned char *section_to_usemap(struct mem_section *ms)
+static inline pageblockflags_t *section_to_usemap(struct mem_section *ms)
{
return ms->usage->pageblock_flags;
}
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 60342e764090..9a41c5dc78eb 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -445,7 +445,7 @@ static inline bool defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
#endif
/* Return a pointer to the bitmap storing bits affecting a block of pages */
-static inline unsigned char *get_pageblock_bitmap(struct page *page,
+static inline pageblockflags_t *get_pageblock_bitmap(struct page *page,
unsigned long pfn)
{
#ifdef CONFIG_SPARSEMEM
@@ -474,24 +474,24 @@ static inline int pfn_to_bitidx(struct page *page, unsigned long pfn)
* Return: pageblock_bits flags
*/
static __always_inline
-unsigned char __get_pfnblock_flags_mask(struct page *page,
+pageblockflags_t __get_pfnblock_flags_mask(struct page *page,
unsigned long pfn,
unsigned long mask)
{
- unsigned char *bitmap;
+ pageblockflags_t *bitmap;
unsigned long bitidx, byte_bitidx;
- unsigned char byte;
+ pageblockflags_t byte;
bitmap = get_pageblock_bitmap(page, pfn);
bitidx = pfn_to_bitidx(page, pfn);
- byte_bitidx = bitidx / BITS_PER_BYTE;
- bitidx &= (BITS_PER_BYTE-1);
+ byte_bitidx = bitidx / BITS_PER_FLAGS;
+ bitidx &= (BITS_PER_FLAGS - 1);
byte = bitmap[byte_bitidx];
return (byte >> bitidx) & mask;
}
-unsigned char get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
+pageblockflags_t get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
unsigned long mask)
{
return __get_pfnblock_flags_mask(page, pfn, mask);
@@ -513,17 +513,17 @@ void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
unsigned long pfn,
unsigned long mask)
{
- unsigned char *bitmap;
+ pageblockflags_t *bitmap;
unsigned long bitidx, byte_bitidx;
- unsigned char old_byte, byte;
+ pageblockflags_t old_byte, byte;
- BUILD_BUG_ON(NR_PAGEBLOCK_BITS != BITS_PER_BYTE);
+ BUILD_BUG_ON(NR_PAGEBLOCK_BITS != BITS_PER_FLAGS);
BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits));
bitmap = get_pageblock_bitmap(page, pfn);
bitidx = pfn_to_bitidx(page, pfn);
- byte_bitidx = bitidx / BITS_PER_BYTE;
- bitidx &= (BITS_PER_BYTE-1);
+ byte_bitidx = bitidx / BITS_PER_FLAGS;
+ bitidx &= (BITS_PER_FLAGS - 1);
VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
--
1.8.3.1
