[PATCH] BLOCK: Move functions out of buffer code [try #6]

[karo-tx-linux.git] / mm / filemap.c

diff --git a/mm/filemap.c b/mm/filemap.c
index 3277f3b2352441eb6d0a5e4d8caf8437bab16460..d6846de0888719308fab1f23c6bfa1442eebda5e 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2491,3 +2491,33 @@ generic_file_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
        }
        return retval;
 }
+
+/**
+ * try_to_release_page() - release old fs-specific metadata on a page
+ *
+ * @page: the page which the kernel is trying to free
+ * @gfp_mask: memory allocation flags (and I/O mode)
+ *
+ * The address_space is to try to release any data against the page
+ * (presumably at page->private).  If the release was successful, return `1'.
+ * Otherwise return zero.
+ *
+ * The @gfp_mask argument specifies whether I/O may be performed to release
+ * this page (__GFP_IO), and whether the call may block (__GFP_WAIT).
+ *
+ * NOTE: @gfp_mask may go away, and this function may become non-blocking.
+ */
+int try_to_release_page(struct page *page, gfp_t gfp_mask)
+{
+       struct address_space * const mapping = page->mapping;
+
+       BUG_ON(!PageLocked(page));
+       if (PageWriteback(page))
+               return 0;
+
+       if (mapping && mapping->a_ops->releasepage)
+               return mapping->a_ops->releasepage(page, gfp_mask);
+       return try_to_free_buffers(page);
+}
+
+EXPORT_SYMBOL(try_to_release_page);