fs: fuse: Workaround for CMA migration
The FUSE file system may hold references to pages for long
periods of time, preventing migration from occuring. If a CMA
page is used here, CMA allocations may fail. Work around this
by swapping out a CMA page for a non-CMA page when working with
the FUSE file system.
Change-Id: Id763ea833ee125c8732ae3759ec9e20d94aa8424
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 504e61b..6e0f58b 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -663,6 +663,42 @@
return PTR_ERR(req);
}
}
+
+#ifdef CONFIG_DMA_CMA
+ if (is_cma_pageblock(page)) {
+ struct page *oldpage = page, *newpage;
+ int err;
+
+ /* make sure that old page is not free in-between the calls */
+ page_cache_get(oldpage);
+
+ newpage = alloc_page(GFP_HIGHUSER);
+ if (!newpage) {
+ page_cache_release(oldpage);
+ return -ENOMEM;
+ }
+
+ err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
+ if (err) {
+ __free_page(newpage);
+ page_cache_release(oldpage);
+ return err;
+ }
+
+ /*
+ * Decrement the count on new page to make page cache the only
+ * owner of it
+ */
+ lock_page(newpage);
+ put_page(newpage);
+
+ /* finally release the old page and swap pointers */
+ unlock_page(oldpage);
+ page_cache_release(oldpage);
+ page = newpage;
+ }
+#endif
+
page_cache_get(page);
req->pages[req->num_pages] = page;
req->num_pages++;