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Commit f1285ff0 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dave Chinner
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xfs: stop using generic_file_read_iter for direct I/O 



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: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent bbc5a740

fs/xfs/xfs_file.c

+13 −2
Original line number Original line Diff line number Diff line
@@ -289,12 +289,17 @@ xfs_file_dio_aio_read( 
	struct address_space	*mapping = iocb->ki_filp->f_mapping;

	struct address_space	*mapping = iocb->ki_filp->f_mapping;

	struct inode		*inode = mapping->host;

	struct inode		*inode = mapping->host;

	struct xfs_inode	*ip = XFS_I(inode);

	struct xfs_inode	*ip = XFS_I(inode);

	loff_t			isize = i_size_read(inode);

	size_t			count = iov_iter_count(to);

	size_t			count = iov_iter_count(to);

	struct iov_iter		data;

	struct xfs_buftarg	*target;

	struct xfs_buftarg	*target;

	ssize_t			ret = 0;

	ssize_t			ret = 0;





	trace_xfs_file_direct_read(ip, count, iocb->ki_pos);

	trace_xfs_file_direct_read(ip, count, iocb->ki_pos);





	if (!count)

		return 0; /* skip atime */



	if (XFS_IS_REALTIME_INODE(ip))

	if (XFS_IS_REALTIME_INODE(ip))

		target = ip->i_mount->m_rtdev_targp;

		target = ip->i_mount->m_rtdev_targp;

	else

	else
@@ -303,7 +308,7 @@ xfs_file_dio_aio_read( 
	if (!IS_DAX(inode)) {

	if (!IS_DAX(inode)) {

		/* DIO must be aligned to device logical sector size */

		/* DIO must be aligned to device logical sector size */

		if ((iocb->ki_pos | count) & target->bt_logical_sectormask) {

		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 0;

			return -EINVAL;

			return -EINVAL;

		}

		}
@@ -354,9 +359,15 @@ xfs_file_dio_aio_read( 
		xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);

		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);

	xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);





	file_accessed(iocb->ki_filp);

	return ret;

	return ret;

}

}