1 files changed, 63 insertions, 43 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 867d40222ec7..645a080ba4df 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -33,7 +33,6 @@
 #include <linux/cpuset.h>
 #include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
 #include <linux/memcontrol.h>
-#include <linux/mm_inline.h> /* for page_is_file_cache() */
 #include <linux/cleancache.h>
 #include "internal.h"
 
@@ -462,6 +461,7 @@ int add_to_page_cache_locked(struct page *page, struct address_space *mapping,
         int error;
 
         VM_BUG_ON(!PageLocked(page));
+        VM_BUG_ON(PageSwapBacked(page));
 
         error = mem_cgroup_cache_charge(page, current->mm,
                                         gfp_mask & GFP_RECLAIM_MASK);
@@ -479,8 +479,6 @@ int add_to_page_cache_locked(struct page *page, struct address_space *mapping,
                 if (likely(!error)) {
                         mapping->nrpages++;
                         __inc_zone_page_state(page, NR_FILE_PAGES);
-                        if (PageSwapBacked(page))
-                                __inc_zone_page_state(page, NR_SHMEM);
                         spin_unlock_irq(&mapping->tree_lock);
                 } else {
                         page->mapping = NULL;
@@ -502,22 +500,9 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
 {
         int ret;
 
-        /*
-         * Splice_read and readahead add shmem/tmpfs pages into the page cache
-         * before shmem_readpage has a chance to mark them as SwapBacked: they
-         * need to go on the anon lru below, and mem_cgroup_cache_charge
-         * (called in add_to_page_cache) needs to know where they're going too.
-         */
-        if (mapping_cap_swap_backed(mapping))
-                SetPageSwapBacked(page);
-
         ret = add_to_page_cache(page, mapping, offset, gfp_mask);
-        if (ret == 0) {
-                if (page_is_file_cache(page))
-                        lru_cache_add_file(page);
-                else
-                        lru_cache_add_anon(page);
-        }
+        if (ret == 0)
+                lru_cache_add_file(page);
         return ret;
 }
 EXPORT_SYMBOL_GPL(add_to_page_cache_lru);
@@ -714,9 +699,16 @@ repeat:
                 page = radix_tree_deref_slot(pagep);
                 if (unlikely(!page))
                         goto out;
-                if (radix_tree_deref_retry(page))
-                        goto repeat;
-
+                if (radix_tree_exception(page)) {
+                        if (radix_tree_deref_retry(page))
+                                goto repeat;
+                        /*
+                         * Otherwise, shmem/tmpfs must be storing a swap entry
+                         * here as an exceptional entry: so return it without
+                         * attempting to raise page count.
+                         */
+                        goto out;
+                }
                 if (!page_cache_get_speculative(page))
                         goto repeat;
 
@@ -753,7 +745,7 @@ struct page *find_lock_page(struct address_space *mapping, pgoff_t offset)
 
 repeat:
         page = find_get_page(mapping, offset);
-        if (page) {
+        if (page && !radix_tree_exception(page)) {
                 lock_page(page);
                 /* Has the page been truncated? */
                 if (unlikely(page->mapping != mapping)) {
@@ -840,7 +832,7 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
         rcu_read_lock();
 restart:
         nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree,
-                                (void ***)pages, start, nr_pages);
+                                (void ***)pages, NULL, start, nr_pages);
         ret = 0;
         for (i = 0; i < nr_found; i++) {
                 struct page *page;
@@ -849,13 +841,22 @@ repeat:
                 if (unlikely(!page))
                         continue;
 
-                /*
-                 * This can only trigger when the entry at index 0 moves out
-                 * of or back to the root: none yet gotten, safe to restart.
-                 */
-                if (radix_tree_deref_retry(page)) {
-                        WARN_ON(start | i);
-                        goto restart;
+                if (radix_tree_exception(page)) {
+                        if (radix_tree_deref_retry(page)) {
+                                /*
+                                 * Transient condition which can only trigger
+                                 * when entry at index 0 moves out of or back
+                                 * to root: none yet gotten, safe to restart.
+                                 */
+                                WARN_ON(start | i);
+                                goto restart;
+                        }
+                        /*
+                         * Otherwise, shmem/tmpfs must be storing a swap entry
+                         * here as an exceptional entry: so skip over it -
+                         * we only reach this from invalidate_mapping_pages().
+                         */
+                        continue;
                 }
 
                 if (!page_cache_get_speculative(page))
@@ -903,7 +904,7 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index,
         rcu_read_lock();
 restart:
         nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree,
-                                (void ***)pages, index, nr_pages);
+                                (void ***)pages, NULL, index, nr_pages);
         ret = 0;
         for (i = 0; i < nr_found; i++) {
                 struct page *page;
@@ -912,12 +913,22 @@ repeat:
                 if (unlikely(!page))
                         continue;
 
-                /*
-                 * This can only trigger when the entry at index 0 moves out
-                 * of or back to the root: none yet gotten, safe to restart.
-                 */
-                if (radix_tree_deref_retry(page))
-                        goto restart;
+                if (radix_tree_exception(page)) {
+                        if (radix_tree_deref_retry(page)) {
+                                /*
+                                 * Transient condition which can only trigger
+                                 * when entry at index 0 moves out of or back
+                                 * to root: none yet gotten, safe to restart.
+                                 */
+                                goto restart;
+                        }
+                        /*
+                         * Otherwise, shmem/tmpfs must be storing a swap entry
+                         * here as an exceptional entry: so stop looking for
+                         * contiguous pages.
+                         */
+                        break;
+                }
 
                 if (!page_cache_get_speculative(page))
                         goto repeat;
@@ -977,12 +988,21 @@ repeat:
                 if (unlikely(!page))
                         continue;
 
-                /*
-                 * This can only trigger when the entry at index 0 moves out
-                 * of or back to the root: none yet gotten, safe to restart.
-                 */
-                if (radix_tree_deref_retry(page))
-                        goto restart;
+                if (radix_tree_exception(page)) {
+                        if (radix_tree_deref_retry(page)) {
+                                /*
+                                 * Transient condition which can only trigger
+                                 * when entry at index 0 moves out of or back
+                                 * to root: none yet gotten, safe to restart.
+                                 */
+                                goto restart;
+                        }
+                        /*
+                         * This function is never used on a shmem/tmpfs
+                         * mapping, so a swap entry won't be found here.
+                         */
+                        BUG();
+                }
 
                 if (!page_cache_get_speculative(page))
                         goto repeat;