From 5a178119b0fbe37f7dfb602b37df9cc4b1dc9d71 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 31 Jul 2012 16:45:02 -0700 Subject: mm: add support for direct_IO to highmem pages The patch "mm: add support for a filesystem to activate swap files and use direct_IO for writing swap pages" added support for using direct_IO to write swap pages but it is insufficient for highmem pages. To support highmem pages, this patch kmaps() the page before calling the direct_IO() handler. As direct_IO deals with virtual addresses an additional helper is necessary for get_kernel_pages() to lookup the struct page for a kmap virtual address. Signed-off-by: Mel Gorman Acked-by: Rik van Riel Cc: Christoph Hellwig Cc: David S. Miller Cc: Eric B Munson Cc: Eric Paris Cc: James Morris Cc: Mel Gorman Cc: Mike Christie Cc: Neil Brown Cc: Peter Zijlstra Cc: Sebastian Andrzej Siewior Cc: Trond Myklebust Cc: Xiaotian Feng Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_io.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'mm/page_io.c') diff --git a/mm/page_io.c b/mm/page_io.c index 4a379629e31f..78eee32ee486 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -205,7 +205,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc) struct file *swap_file = sis->swap_file; struct address_space *mapping = swap_file->f_mapping; struct iovec iov = { - .iov_base = page_address(page), + .iov_base = kmap(page), .iov_len = PAGE_SIZE, }; @@ -218,6 +218,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc) ret = mapping->a_ops->direct_IO(KERNEL_WRITE, &kiocb, &iov, kiocb.ki_pos, 1); + kunmap(page); if (ret == PAGE_SIZE) { count_vm_event(PSWPOUT); ret = 0; -- cgit v1.2.3-59-g8ed1b