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@@ -972,20 +972,7 @@ found:
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error = add_to_page_cache_locked(page, mapping, idx, GFP_NOWAIT);
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/* which does mem_cgroup_uncharge_cache_page on error */
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- if (error == -EEXIST) {
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- struct page *filepage = find_get_page(mapping, idx);
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- error = 1;
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- if (filepage) {
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- /*
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- * There might be a more uptodate page coming down
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- * from a stacked writepage: forget our swappage if so.
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- */
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- if (PageUptodate(filepage))
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- error = 0;
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- page_cache_release(filepage);
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- }
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- }
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- if (!error) {
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+ if (error != -ENOMEM) {
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delete_from_swap_cache(page);
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set_page_dirty(page);
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info->flags |= SHMEM_PAGEIN;
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@@ -1072,16 +1059,17 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
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/*
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* shmem_backing_dev_info's capabilities prevent regular writeback or
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* sync from ever calling shmem_writepage; but a stacking filesystem
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- * may use the ->writepage of its underlying filesystem, in which case
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+ * might use ->writepage of its underlying filesystem, in which case
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* tmpfs should write out to swap only in response to memory pressure,
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- * and not for the writeback threads or sync. However, in those cases,
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- * we do still want to check if there's a redundant swappage to be
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- * discarded.
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+ * and not for the writeback threads or sync.
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*/
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- if (wbc->for_reclaim)
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- swap = get_swap_page();
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- else
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- swap.val = 0;
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+ if (!wbc->for_reclaim) {
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+ WARN_ON_ONCE(1); /* Still happens? Tell us about it! */
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+ goto redirty;
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+ }
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+ swap = get_swap_page();
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+ if (!swap.val)
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+ goto redirty;
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/*
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* Add inode to shmem_unuse()'s list of swapped-out inodes,
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@@ -1092,15 +1080,12 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
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* we've taken the spinlock, because shmem_unuse_inode() will
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* prune a !swapped inode from the swaplist under both locks.
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*/
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- if (swap.val) {
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- mutex_lock(&shmem_swaplist_mutex);
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- if (list_empty(&info->swaplist))
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- list_add_tail(&info->swaplist, &shmem_swaplist);
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- }
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+ mutex_lock(&shmem_swaplist_mutex);
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+ if (list_empty(&info->swaplist))
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+ list_add_tail(&info->swaplist, &shmem_swaplist);
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spin_lock(&info->lock);
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- if (swap.val)
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- mutex_unlock(&shmem_swaplist_mutex);
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+ mutex_unlock(&shmem_swaplist_mutex);
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if (index >= info->next_index) {
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BUG_ON(!(info->flags & SHMEM_TRUNCATE));
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@@ -1108,16 +1093,13 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
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}
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entry = shmem_swp_entry(info, index, NULL);
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if (entry->val) {
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- /*
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- * The more uptodate page coming down from a stacked
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- * writepage should replace our old swappage.
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- */
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+ WARN_ON_ONCE(1); /* Still happens? Tell us about it! */
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free_swap_and_cache(*entry);
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shmem_swp_set(info, entry, 0);
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}
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shmem_recalc_inode(inode);
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- if (swap.val && add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
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+ if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
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delete_from_page_cache(page);
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shmem_swp_set(info, entry, swap.val);
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shmem_swp_unmap(entry);
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