shmem: fix splicing from a hole while it's punched

[platform/adaptation/renesas_rcar/renesas_kernel.git] / mm / shmem.c

diff --git a/mm/shmem.c b/mm/shmem.c
index fd4ea4b..ff85863 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -534,22 +534,19 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
                return;
 
        index = start;
-       for ( ; ; ) {
+       while (index < end) {
                cond_resched();
                pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
                                min(end - index, (pgoff_t)PAGEVEC_SIZE),
                                                        pvec.pages, indices);
                if (!pvec.nr) {
-                       if (index == start || unfalloc)
+                       /* If all gone or hole-punch or unfalloc, we're done */
+                       if (index == start || end != -1)
                                break;
+                       /* But if truncating, restart to make sure all gone */
                        index = start;
                        continue;
                }
-               if ((index == start || unfalloc) && indices[0] >= end) {
-                       shmem_deswap_pagevec(&pvec);
-                       pagevec_release(&pvec);
-                       break;
-               }
                mem_cgroup_uncharge_start();
                for (i = 0; i < pagevec_count(&pvec); i++) {
                        struct page *page = pvec.pages[i];
@@ -561,8 +558,12 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
                        if (radix_tree_exceptional_entry(page)) {
                                if (unfalloc)
                                        continue;
-                               nr_swaps_freed += !shmem_free_swap(mapping,
-                                                               index, page);
+                               if (shmem_free_swap(mapping, index, page)) {
+                                       /* Swap was replaced by page: retry */
+                                       index--;
+                                       break;
+                               }
+                               nr_swaps_freed++;
                                continue;
                        }
 
@@ -571,6 +572,11 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
                                if (page->mapping == mapping) {
                                        VM_BUG_ON_PAGE(PageWriteback(page), page);
                                        truncate_inode_page(mapping, page);
+                               } else {
+                                       /* Page was replaced by swap: retry */
+                                       unlock_page(page);
+                                       index--;
+                                       break;
                                }
                        }
                        unlock_page(page);