Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-pd0-f169.google.com ([209.85.192.169]:44185 "EHLO mail-pd0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751908AbaKULEc (ORCPT ); Fri, 21 Nov 2014 06:04:32 -0500 Received: by mail-pd0-f169.google.com with SMTP id fp1so5070500pdb.0 for ; Fri, 21 Nov 2014 03:04:32 -0800 (PST) From: Omar Sandoval To: Alexander Viro , Andrew Morton , Chris Mason , Josef Bacik , linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-nfs@vger.kernel.org, Trond Myklebust , Mel Gorman Cc: Omar Sandoval Subject: [PATCH v2 3/5] swap: use direct I/O for SWP_FILE swap_readpage Date: Fri, 21 Nov 2014 02:08:29 -0800 Message-Id: <455265ec2174096758e3d702a1e8c84aff46aa72.1416563833.git.osandov@osandov.com> In-Reply-To: References: In-Reply-To: References: Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Nov 17, 2014 at 07:48:17AM -0800, Christoph Hellwig wrote: > With the new iov_iter infrastructure that supprots direct I/O to kernel > pages please get rid of the ->readpage hack first. I'm still utterly > disapoined that this crap ever got merged. Cc: Mel Gorman Signed-off-by: Omar Sandoval --- mm/page_io.c | 32 ++++++++++++++++++++++++++++---- 1 file changed, 28 insertions(+), 4 deletions(-) diff --git a/mm/page_io.c b/mm/page_io.c index 955db8b..10715e0 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -283,8 +283,7 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc, set_page_writeback(page); unlock_page(page); - ret = mapping->a_ops->direct_IO(ITER_BVEC | WRITE, - &kiocb, &from, + ret = mapping->a_ops->direct_IO(WRITE, &kiocb, &from, kiocb.ki_pos); if (ret == PAGE_SIZE) { count_vm_event(PSWPOUT); @@ -348,12 +347,37 @@ int swap_readpage(struct page *page) } if (sis->flags & SWP_FILE) { + struct kiocb kiocb; struct file *swap_file = sis->swap_file; struct address_space *mapping = swap_file->f_mapping; + struct bio_vec bv = { + .bv_page = page, + .bv_len = PAGE_SIZE, + .bv_offset = 0, + }; + struct iov_iter to = { + .type = ITER_BVEC | READ, + .count = PAGE_SIZE, + .iov_offset = 0, + .nr_segs = 1, + }; + to.bvec = &bv; /* older gcc versions are broken */ + + init_sync_kiocb(&kiocb, swap_file); + kiocb.ki_pos = page_file_offset(page); + kiocb.ki_nbytes = PAGE_SIZE; - ret = mapping->a_ops->readpage(swap_file, page); - if (!ret) + ret = mapping->a_ops->direct_IO(READ, &kiocb, &to, + kiocb.ki_pos); + if (ret == PAGE_SIZE) { + SetPageUptodate(page); count_vm_event(PSWPIN); + ret = 0; + } else { + ClearPageUptodate(page); + SetPageError(page); + } + unlock_page(page); return ret; } -- 2.1.3