From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([198.137.202.9]:52901 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752027AbcFVPoY (ORCPT ); Wed, 22 Jun 2016 11:44:24 -0400 From: Christoph Hellwig To: xfs@oss.sgi.com Cc: linux-nvdimm@ml01.01.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 5/8] xfs: stop using generic_file_read_iter for direct I/O Date: Wed, 22 Jun 2016 17:27:13 +0200 Message-Id: <1466609236-23801-6-git-send-email-hch@lst.de> In-Reply-To: <1466609236-23801-1-git-send-email-hch@lst.de> References: <1466609236-23801-1-git-send-email-hch@lst.de> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: XFS already implement it's own flushing of the pagecache because it implements proper synchronization for direct I/O reads. This means calling generic_file_read_iter for direct I/O is rather useless, as it doesn't do much but updating the atime and iocb position for us. This also gets rid of the buffered I/O fallback that isn't used for XFS. Signed-off-by: Christoph Hellwig --- fs/xfs/xfs_file.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index e584333..f761f49 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -246,12 +246,17 @@ xfs_file_dio_aio_read( struct address_space *mapping = iocb->ki_filp->f_mapping; struct inode *inode = mapping->host; struct xfs_inode *ip = XFS_I(inode); + loff_t isize = i_size_read(inode); size_t count = iov_iter_count(to); + struct iov_iter data; struct xfs_buftarg *target; ssize_t ret = 0; trace_xfs_file_direct_read(ip, count, iocb->ki_pos); + if (!count) + return 0; /* skip atime */ + if (XFS_IS_REALTIME_INODE(ip)) target = ip->i_mount->m_rtdev_targp; else @@ -260,7 +265,7 @@ xfs_file_dio_aio_read( if (!IS_DAX(inode)) { /* DIO must be aligned to device logical sector size */ if ((iocb->ki_pos | count) & target->bt_logical_sectormask) { - if (iocb->ki_pos == i_size_read(inode)) + if (iocb->ki_pos == isize) return 0; return -EINVAL; } @@ -311,9 +316,15 @@ xfs_file_dio_aio_read( xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL); } - ret = generic_file_read_iter(iocb, to); + data = *to; + ret = mapping->a_ops->direct_IO(iocb, &data); + if (ret > 0) { + iocb->ki_pos += ret; + iov_iter_advance(to, ret); + } xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED); + file_accessed(iocb->ki_filp); return ret; } -- 2.1.4