1 files changed, 55 insertions, 90 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 71373d03fcee..14e254c768fc 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -33,6 +33,7 @@
 #include <linux/oom.h>
 #include <linux/frontswap.h>
 #include <linux/swapfile.h>
+#include <linux/export.h>
 
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
@@ -548,7 +549,6 @@ static unsigned char swap_entry_free(struct swap_info_struct *p,
 
 	/* free if no reference */
 	if (!usage) {
-		struct gendisk *disk = p->bdev->bd_disk;
 		if (offset < p->lowest_bit)
 			p->lowest_bit = offset;
 		if (offset > p->highest_bit)
@@ -559,9 +559,12 @@ static unsigned char swap_entry_free(struct swap_info_struct *p,
 		nr_swap_pages++;
 		p->inuse_pages--;
 		frontswap_invalidate_page(p->type, offset);
-		if ((p->flags & SWP_BLKDEV) &&
-				disk->fops->swap_slot_free_notify)
-			disk->fops->swap_slot_free_notify(p->bdev, offset);
+		if (p->flags & SWP_BLKDEV) {
+			struct gendisk *disk = p->bdev->bd_disk;
+			if (disk->fops->swap_slot_free_notify)
+				disk->fops->swap_slot_free_notify(p->bdev,
+								  offset);
+		}
 	}
 
 	return usage;
@@ -832,8 +835,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
 
 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
 	if (unlikely(!pte_same(*pte, swp_entry_to_pte(entry)))) {
-		if (ret > 0)
-			mem_cgroup_cancel_charge_swapin(memcg);
+		mem_cgroup_cancel_charge_swapin(memcg);
 		ret = 0;
 		goto out;
 	}
@@ -1328,6 +1330,14 @@ static void destroy_swap_extents(struct swap_info_struct *sis)
 		list_del(&se->list);
 		kfree(se);
 	}
+
+	if (sis->flags & SWP_FILE) {
+		struct file *swap_file = sis->swap_file;
+		struct address_space *mapping = swap_file->f_mapping;
+
+		sis->flags &= ~SWP_FILE;
+		mapping->a_ops->swap_deactivate(swap_file);
+	}
 }
 
 /*
@@ -1336,7 +1346,7 @@ static void destroy_swap_extents(struct swap_info_struct *sis)
  *
  * This function rather assumes that it is called in ascending page order.
  */
-static int
+int
 add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
 		unsigned long nr_pages, sector_t start_block)
 {
@@ -1409,98 +1419,28 @@ add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
  */
 static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span)
 {
-	struct inode *inode;
-	unsigned blocks_per_page;
-	unsigned long page_no;
-	unsigned blkbits;
-	sector_t probe_block;
-	sector_t last_block;
-	sector_t lowest_block = -1;
-	sector_t highest_block = 0;
-	int nr_extents = 0;
+	struct file *swap_file = sis->swap_file;
+	struct address_space *mapping = swap_file->f_mapping;
+	struct inode *inode = mapping->host;
 	int ret;
 
-	inode = sis->swap_file->f_mapping->host;
 	if (S_ISBLK(inode->i_mode)) {
 		ret = add_swap_extent(sis, 0, sis->max, 0);
 		*span = sis->pages;
-		goto out;
+		return ret;
 	}
 
-	blkbits = inode->i_blkbits;
-	blocks_per_page = PAGE_SIZE >> blkbits;
-
-	/*
-	 * Map all the blocks into the extent list.  This code doesn't try
-	 * to be very smart.
-	 */
-	probe_block = 0;
-	page_no = 0;
-	last_block = i_size_read(inode) >> blkbits;
-	while ((probe_block + blocks_per_page) <= last_block &&
-			page_no < sis->max) {
-		unsigned block_in_page;
-		sector_t first_block;
-
-		first_block = bmap(inode, probe_block);
-		if (first_block == 0)
-			goto bad_bmap;
-
-		/*
-		 * It must be PAGE_SIZE aligned on-disk
-		 */
-		if (first_block & (blocks_per_page - 1)) {
-			probe_block++;
-			goto reprobe;
-		}
-
-		for (block_in_page = 1; block_in_page < blocks_per_page;
-					block_in_page++) {
-			sector_t block;
-
-			block = bmap(inode, probe_block + block_in_page);
-			if (block == 0)
-				goto bad_bmap;
-			if (block != first_block + block_in_page) {
-				/* Discontiguity */
-				probe_block++;
-				goto reprobe;
-			}
-		}
-
-		first_block >>= (PAGE_SHIFT - blkbits);
-		if (page_no) {	/* exclude the header page */
-			if (first_block < lowest_block)
-				lowest_block = first_block;
-			if (first_block > highest_block)
-				highest_block = first_block;
+	if (mapping->a_ops->swap_activate) {
+		ret = mapping->a_ops->swap_activate(sis, swap_file, span);
+		if (!ret) {
+			sis->flags |= SWP_FILE;
+			ret = add_swap_extent(sis, 0, sis->max, 0);
+			*span = sis->pages;
 		}
+		return ret;
+	}
 
-		/*
-		 * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
-		 */
-		ret = add_swap_extent(sis, page_no, 1, first_block);
-		if (ret < 0)
-			goto out;
-		nr_extents += ret;
-		page_no++;
-		probe_block += blocks_per_page;
-reprobe:
-		continue;
-	}
-	ret = nr_extents;
-	*span = 1 + highest_block - lowest_block;
-	if (page_no == 0)
-		page_no = 1;	/* force Empty message */
-	sis->max = page_no;
-	sis->pages = page_no - 1;
-	sis->highest_bit = page_no - 1;
-out:
-	return ret;
-bad_bmap:
-	printk(KERN_ERR "swapon: swapfile has holes\n");
-	ret = -EINVAL;
-	goto out;
+	return generic_swapfile_activate(sis, swap_file, span);
 }
 
 static void enable_swap_info(struct swap_info_struct *p, int prio,
@@ -2285,6 +2225,31 @@ int swapcache_prepare(swp_entry_t entry)
 	return __swap_duplicate(entry, SWAP_HAS_CACHE);
 }
 
+struct swap_info_struct *page_swap_info(struct page *page)
+{
+	swp_entry_t swap = { .val = page_private(page) };
+	BUG_ON(!PageSwapCache(page));
+	return swap_info[swp_type(swap)];
+}
+
+/*
+ * out-of-line __page_file_ methods to avoid include hell.
+ */
+struct address_space *__page_file_mapping(struct page *page)
+{
+	VM_BUG_ON(!PageSwapCache(page));
+	return page_swap_info(page)->swap_file->f_mapping;
+}
+EXPORT_SYMBOL_GPL(__page_file_mapping);
+
+pgoff_t __page_file_index(struct page *page)
+{
+	swp_entry_t swap = { .val = page_private(page) };
+	VM_BUG_ON(!PageSwapCache(page));
+	return swp_offset(swap);
+}
+EXPORT_SYMBOL_GPL(__page_file_index);
+
 /*
  * add_swap_count_continuation - called when a swap count is duplicated
  * beyond SWAP_MAP_MAX, it allocates a new page and links that to the entry's