[PATCH] use page_to_pfn() instead of mem_map[]

A patch from Martin Bligh which cleans up the open-coded uses of
mem_map for ia32.  Basically it replaces

mem_map + pagenr

with

pfn_to_page(pagenr)

in lots of places.  Because mem_map[] doesn't work like that with
discontigmem.

It also fixes a bug in bad_range, that happens to work for contig mem
systems, but is incorrect.  Tested both with and without discontigmem
support.

arch/i386/mm/init.c

@@ -235,7 +235,7 @@ void __init set_highmem_pages_init(int bad_ppro)
 {
 	int pfn;
 	for (pfn = highstart_pfn; pfn < highend_pfn; pfn++)
-		one_highpage_init((struct page *)(mem_map + pfn), pfn, bad_ppro);
+		one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro);
 	totalram_pages += totalhigh_pages;
 }
 #else
@@ -419,7 +419,7 @@ void __init test_wp_bit(void)
 static void __init set_max_mapnr_init(void)
 {
 #ifdef CONFIG_HIGHMEM
-	highmem_start_page = mem_map + highstart_pfn;
+	highmem_start_page = pfn_to_page(highstart_pfn);
 	max_mapnr = num_physpages = highend_pfn;
 #else
 	max_mapnr = num_physpages = max_low_pfn;
@@ -458,7 +458,7 @@ void __init mem_init(void)
 		/*
 		 * Only count reserved RAM pages
 		 */
-		if (page_is_ram(tmp) && PageReserved(mem_map+tmp))
+		if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
 			reservedpages++;
 
 	set_highmem_pages_init(bad_ppro);

arch/i386/mm/pgtable.c

@@ -22,24 +22,26 @@
 
 void show_mem(void)
 {
-	int i, total = 0, reserved = 0;
+	int pfn, total = 0, reserved = 0;
 	int shared = 0, cached = 0;
 	int highmem = 0;
+	struct page *page;
 
 	printk("Mem-info:\n");
 	show_free_areas();
 	printk("Free swap:       %6dkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
-	i = max_mapnr;
-	while (i-- > 0) {
+	pfn = max_mapnr;
+	while (pfn-- > 0) {
+		page = pfn_to_page(pfn);
 		total++;
-		if (PageHighMem(mem_map+i))
+		if (PageHighMem(page))
 			highmem++;
-		if (PageReserved(mem_map+i))
+		if (PageReserved(page))
 			reserved++;
-		else if (PageSwapCache(mem_map+i))
+		else if (PageSwapCache(page))
 			cached++;
-		else if (page_count(mem_map+i))
-			shared += page_count(mem_map+i) - 1;
+		else if (page_count(page))
+			shared += page_count(page) - 1;
 	}
 	printk("%d pages of RAM\n", total);
 	printk("%d pages of HIGHMEM\n",highmem);

drivers/net/ns83820.c

@@ -1081,7 +1081,7 @@ static int ns83820_hard_start_xmit(struct sk_buff *skb, struct net_device *_dev)
 				   frag->page_offset,
 				   frag->size, PCI_DMA_TODEVICE);
 		dprintk("frag: buf=%08Lx  page=%08lx offset=%08lx\n",
-			(long long)buf, (long)(frag->page - mem_map),
+			(long long)buf, (long) page_to_pfn(frag->page),
 			frag->page_offset);
 		len = frag->size;
 		frag++;

include/asm-i386/io.h

@@ -96,23 +96,7 @@ static inline void * phys_to_virt(unsigned long address)
 /*
  * Change "struct page" to physical address.
  */
-#ifdef CONFIG_HIGHMEM64G
-
-#ifndef CONFIG_DISCONTIGMEM
-#define page_to_phys(page)	((u64)(page - mem_map) << PAGE_SHIFT)
-#else
-#define page_to_phys(page)	((u64)(page - page_zone(page)->zone_mem_map + page_zone(page)->zone_start_pfn) << PAGE_SHIFT)
-#endif /* !CONFIG_DISCONTIGMEM */
-
-#else
-
-#ifndef CONFIG_DISCONTIGMEM
-#define page_to_phys(page)	((page - mem_map) << PAGE_SHIFT)
-#else
-#define page_to_phys(page)	((page - page_zone(page)->zone_mem_map + page_zone(page)->zone_start_pfn) << PAGE_SHIFT)
-#endif /* !CONFIG_DISCONTIGMEM */
-
-#endif /* CONFIG_HIGHMEM64G */
+#define page_to_phys(page)    ((dma_addr_t)page_to_pfn(page) << PAGE_SHIFT)
 
 extern void * __ioremap(unsigned long offset, unsigned long size, unsigned long flags);
 

include/asm-i386/pci.h

@@ -107,7 +107,7 @@ static inline dma_addr_t pci_map_page(struct pci_dev *hwdev, struct page *page,
 	if (direction == PCI_DMA_NONE)
 		BUG();
 
-	return (dma_addr_t)(page - mem_map) * PAGE_SIZE + offset;
+	return (dma_addr_t)(page_to_pfn(page)) * PAGE_SIZE + offset;
 }
 
 static inline void pci_unmap_page(struct pci_dev *hwdev, dma_addr_t dma_address,
@@ -236,9 +236,7 @@ pci_dac_page_to_dma(struct pci_dev *pdev, struct page *page, unsigned long offse
 static __inline__ struct page *
 pci_dac_dma_to_page(struct pci_dev *pdev, dma64_addr_t dma_addr)
 {
-	unsigned long poff = (dma_addr >> PAGE_SHIFT);
-
-	return mem_map + poff;
+	return pfn_to_page(dma_addr >> PAGE_SHIFT);
 }
 
 static __inline__ unsigned long

include/asm-i386/pgalloc.h

@@ -13,7 +13,7 @@
 static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, struct page *pte)
 {
 	set_pmd(pmd, __pmd(_PAGE_TABLE +
-		((unsigned long long)(pte - mem_map) <<
+		((unsigned long long)page_to_pfn(pte) <<
 			(unsigned long long) PAGE_SHIFT)));
 }
 /*

include/asm-i386/pgtable.h

@@ -235,8 +235,7 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
 
 #ifndef CONFIG_DISCONTIGMEM
-#define pmd_page(pmd) \
-	(mem_map + (pmd_val(pmd) >> PAGE_SHIFT))
+#define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
 #endif /* !CONFIG_DISCONTIGMEM */
 
 #define pmd_large(pmd) \

kernel/suspend.c

@@ -468,31 +468,33 @@ static int count_and_copy_data_pages(struct pbe *pagedir_p)
 {
 	int chunk_size;
 	int nr_copy_pages = 0;
-	int loop;
+	int pfn;
+	struct page *page;
 	
 	if (max_mapnr != num_physpages)
 		panic("mapnr is not expected");
-	for (loop = 0; loop < max_mapnr; loop++) {
-		if (PageHighMem(mem_map+loop))
+	for (pfn = 0; pfn < max_mapnr; pfn++) {
+		page = pfn_to_page(pfn);
+		if (PageHighMem(page))
 			panic("Swsusp not supported on highmem boxes. Send 1GB of RAM to <pavel@ucw.cz> and try again ;-).");
-		if (!PageReserved(mem_map+loop)) {
-			if (PageNosave(mem_map+loop))
+		if (!PageReserved(page)) {
+			if (PageNosave(page))
 				continue;
 
-			if ((chunk_size=is_head_of_free_region(mem_map+loop))!=0) {
-				loop += chunk_size - 1;
+			if ((chunk_size=is_head_of_free_region(page))!=0) {
+				pfn += chunk_size - 1;
 				continue;
 			}
-		} else if (PageReserved(mem_map+loop)) {
-			BUG_ON (PageNosave(mem_map+loop));
+		} else if (PageReserved(page)) {
+			BUG_ON (PageNosave(page));
 
 			/*
 			 * Just copy whole code segment. Hopefully it is not that big.
 			 */
-			if (ADDRESS(loop) >= (unsigned long)
-				&__nosave_begin && ADDRESS(loop) < 
+			if (ADDRESS(pfn) >= (unsigned long)
+				&__nosave_begin && ADDRESS(pfn) < 
 				(unsigned long)&__nosave_end) {
-				PRINTK("[nosave %x]", ADDRESS(loop));
+				PRINTK("[nosave %x]", ADDRESS(pfn));
 				continue;
 			}
 			/* Hmm, perhaps copying all reserved pages is not too healthy as they may contain 
@@ -501,7 +503,7 @@ static int count_and_copy_data_pages(struct pbe *pagedir_p)
 
 		nr_copy_pages++;
 		if (pagedir_p) {
-			pagedir_p->orig_address = ADDRESS(loop);
+			pagedir_p->orig_address = ADDRESS(pfn);
 			copy_page(pagedir_p->address, pagedir_p->orig_address);
 			pagedir_p++;
 		}

mm/page_alloc.c

@@ -46,9 +46,9 @@ static int zone_balance_max[MAX_NR_ZONES] __initdata = { 255 , 255, 255, };
  */
 static inline int bad_range(struct zone *zone, struct page *page)
 {
-	if (page - mem_map >= zone->zone_start_mapnr + zone->size)
+	if (page_to_pfn(page) >= zone->zone_start_pfn + zone->size)
 		return 1;
-	if (page - mem_map < zone->zone_start_mapnr)
+	if (page_to_pfn(page) < zone->zone_start_pfn)
 		return 1;
 	if (zone != page_zone(page))
 		return 1;