1 files changed, 100 insertions, 111 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 457b10baef59..14e254c768fc 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -31,6 +31,9 @@
 #include <linux/memcontrol.h>
 #include <linux/poll.h>
 #include <linux/oom.h>
+#include <linux/frontswap.h>
+#include <linux/swapfile.h>
+#include <linux/export.h>
 
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
@@ -42,7 +45,7 @@ static bool swap_count_continued(struct swap_info_struct *, pgoff_t,
 static void free_swap_count_continuations(struct swap_info_struct *);
 static sector_t map_swap_entry(swp_entry_t, struct block_device**);
 
-static DEFINE_SPINLOCK(swap_lock);
+DEFINE_SPINLOCK(swap_lock);
 static unsigned int nr_swapfiles;
 long nr_swap_pages;
 long total_swap_pages;
@@ -53,9 +56,9 @@ static const char Unused_file[] = "Unused swap file entry ";
 static const char Bad_offset[] = "Bad swap offset entry ";
 static const char Unused_offset[] = "Unused swap offset entry ";
 
-static struct swap_list_t swap_list = {-1, -1};
+struct swap_list_t swap_list = {-1, -1};
 
-static struct swap_info_struct *swap_info[MAX_SWAPFILES];
+struct swap_info_struct *swap_info[MAX_SWAPFILES];
 
 static DEFINE_MUTEX(swapon_mutex);
 
@@ -546,7 +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)
@@ -556,9 +558,13 @@ static unsigned char swap_entry_free(struct swap_info_struct *p,
 			swap_list.next = p->type;
 		nr_swap_pages++;
 		p->inuse_pages--;
-		if ((p->flags & SWP_BLKDEV) &&
-				disk->fops->swap_slot_free_notify)
-			disk->fops->swap_slot_free_notify(p->bdev, offset);
+		frontswap_invalidate_page(p->type, 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;
@@ -829,8 +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;
 	}
@@ -985,11 +990,12 @@ static int unuse_mm(struct mm_struct *mm,
 }
 
 /*
- * Scan swap_map from current position to next entry still in use.
+ * Scan swap_map (or frontswap_map if frontswap parameter is true)
+ * from current position to next entry still in use.
  * Recycle to start on reaching the end, returning 0 when empty.
  */
 static unsigned int find_next_to_unuse(struct swap_info_struct *si,
-					unsigned int prev)
+					unsigned int prev, bool frontswap)
 {
 	unsigned int max = si->max;
 	unsigned int i = prev;
@@ -1015,6 +1021,12 @@ static unsigned int find_next_to_unuse(struct swap_info_struct *si,
 			prev = 0;
 			i = 1;
 		}
+		if (frontswap) {
+			if (frontswap_test(si, i))
+				break;
+			else
+				continue;
+		}
 		count = si->swap_map[i];
 		if (count && swap_count(count) != SWAP_MAP_BAD)
 			break;
@@ -1026,8 +1038,12 @@ static unsigned int find_next_to_unuse(struct swap_info_struct *si,
  * We completely avoid races by reading each swap page in advance,
  * and then search for the process using it.  All the necessary
  * page table adjustments can then be made atomically.
+ *
+ * if the boolean frontswap is true, only unuse pages_to_unuse pages;
+ * pages_to_unuse==0 means all pages; ignored if frontswap is false
  */
-static int try_to_unuse(unsigned int type)
+int try_to_unuse(unsigned int type, bool frontswap,
+		 unsigned long pages_to_unuse)
 {
 	struct swap_info_struct *si = swap_info[type];
 	struct mm_struct *start_mm;
@@ -1060,7 +1076,7 @@ static int try_to_unuse(unsigned int type)
 	 * one pass through swap_map is enough, but not necessarily:
 	 * there are races when an instance of an entry might be missed.
 	 */
-	while ((i = find_next_to_unuse(si, i)) != 0) {
+	while ((i = find_next_to_unuse(si, i, frontswap)) != 0) {
 		if (signal_pending(current)) {
 			retval = -EINTR;
 			break;
@@ -1227,6 +1243,10 @@ static int try_to_unuse(unsigned int type)
 		 * interactive performance.
 		 */
 		cond_resched();
+		if (frontswap && pages_to_unuse > 0) {
+			if (!--pages_to_unuse)
+				break;
+		}
 	}
 
 	mmput(start_mm);
@@ -1310,6 +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);
+	}
 }
 
 /*
@@ -1318,7 +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)
 {
@@ -1391,102 +1419,33 @@ 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,
-				unsigned char *swap_map)
+				unsigned char *swap_map,
+				unsigned long *frontswap_map)
 {
 	int i, prev;
 
@@ -1496,6 +1455,7 @@ static void enable_swap_info(struct swap_info_struct *p, int prio,
 	else
 		p->prio = --least_priority;
 	p->swap_map = swap_map;
+	frontswap_map_set(p, frontswap_map);
 	p->flags |= SWP_WRITEOK;
 	nr_swap_pages += p->pages;
 	total_swap_pages += p->pages;
@@ -1512,6 +1472,7 @@ static void enable_swap_info(struct swap_info_struct *p, int prio,
 		swap_list.head = swap_list.next = p->type;
 	else
 		swap_info[prev]->next = p->type;
+	frontswap_init(p->type);
 	spin_unlock(&swap_lock);
 }
 
@@ -1585,7 +1546,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
 	spin_unlock(&swap_lock);
 
 	oom_score_adj = test_set_oom_score_adj(OOM_SCORE_ADJ_MAX);
-	err = try_to_unuse(type);
+	err = try_to_unuse(type, false, 0); /* force all pages to be unused */
 	compare_swap_oom_score_adj(OOM_SCORE_ADJ_MAX, oom_score_adj);
 
 	if (err) {
@@ -1596,7 +1557,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
 		 * sys_swapoff for this swap_info_struct at this point.
 		 */
 		/* re-insert swap space back into swap_list */
-		enable_swap_info(p, p->prio, p->swap_map);
+		enable_swap_info(p, p->prio, p->swap_map, frontswap_map_get(p));
 		goto out_dput;
 	}
 
@@ -1622,9 +1583,11 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
 	swap_map = p->swap_map;
 	p->swap_map = NULL;
 	p->flags = 0;
+	frontswap_invalidate_area(type);
 	spin_unlock(&swap_lock);
 	mutex_unlock(&swapon_mutex);
 	vfree(swap_map);
+	vfree(frontswap_map_get(p));
 	/* Destroy swap account informatin */
 	swap_cgroup_swapoff(type);
 
@@ -1893,24 +1856,20 @@ static unsigned long read_swap_header(struct swap_info_struct *p,
 
 	/*
 	 * Find out how many pages are allowed for a single swap
-	 * device. There are three limiting factors: 1) the number
+	 * device. There are two limiting factors: 1) the number
 	 * of bits for the swap offset in the swp_entry_t type, and
 	 * 2) the number of bits in the swap pte as defined by the
-	 * the different architectures, and 3) the number of free bits
-	 * in an exceptional radix_tree entry. In order to find the
+	 * different architectures. In order to find the
 	 * largest possible bit mask, a swap entry with swap type 0
 	 * and swap offset ~0UL is created, encoded to a swap pte,
 	 * decoded to a swp_entry_t again, and finally the swap
 	 * offset is extracted. This will mask all the bits from
 	 * the initial ~0UL mask that can't be encoded in either
 	 * the swp_entry_t or the architecture definition of a
-	 * swap pte.  Then the same is done for a radix_tree entry.
+	 * swap pte.
 	 */
 	maxpages = swp_offset(pte_to_swp_entry(
-			swp_entry_to_pte(swp_entry(0, ~0UL))));
-	maxpages = swp_offset(radix_to_swp_entry(
-			swp_to_radix_entry(swp_entry(0, maxpages)))) + 1;
-
+			swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1;
 	if (maxpages > swap_header->info.last_page) {
 		maxpages = swap_header->info.last_page + 1;
 		/* p->max is an unsigned int: don't overflow it */
@@ -1988,6 +1947,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 	sector_t span;
 	unsigned long maxpages;
 	unsigned char *swap_map = NULL;
+	unsigned long *frontswap_map = NULL;
 	struct page *page = NULL;
 	struct inode *inode = NULL;
 
@@ -2071,6 +2031,9 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 		error = nr_extents;
 		goto bad_swap;
 	}
+	/* frontswap enabled? set up bit-per-page map for frontswap */
+	if (frontswap_enabled)
+		frontswap_map = vzalloc(maxpages / sizeof(long));
 
 	if (p->bdev) {
 		if (blk_queue_nonrot(bdev_get_queue(p->bdev))) {
@@ -2086,14 +2049,15 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 	if (swap_flags & SWAP_FLAG_PREFER)
 		prio =
 		  (swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT;
-	enable_swap_info(p, prio, swap_map);
+	enable_swap_info(p, prio, swap_map, frontswap_map);
 
 	printk(KERN_INFO "Adding %uk swap on %s.  "
-			"Priority:%d extents:%d across:%lluk %s%s\n",
+			"Priority:%d extents:%d across:%lluk %s%s%s\n",
 		p->pages<<(PAGE_SHIFT-10), name, p->prio,
 		nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10),
 		(p->flags & SWP_SOLIDSTATE) ? "SS" : "",
-		(p->flags & SWP_DISCARDABLE) ? "D" : "");
+		(p->flags & SWP_DISCARDABLE) ? "D" : "",
+		(frontswap_map) ? "FS" : "");
 
 	mutex_unlock(&swapon_mutex);
 	atomic_inc(&proc_poll_event);
@@ -2261,6 +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