From 5fe878ae7f82fbf0830dbfaee4c5ca18f3aee442 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 15 Dec 2009 16:47:50 -0800 Subject: direct-io: cleanup blockdev_direct_IO locking Currently the locking in blockdev_direct_IO is a mess, we have three different locking types and very confusing checks for some of them. The most complicated one is DIO_OWN_LOCKING for reads, which happens to not actually be used. This patch gets rid of the DIO_OWN_LOCKING - as mentioned above the read case is unused anyway, and the write side is almost identical to DIO_NO_LOCKING. The difference is that DIO_NO_LOCKING always sets the create argument for the get_blocks callback to zero, but we can easily move that to the actual get_blocks callbacks. There are four users of the DIO_NO_LOCKING mode: gfs already ignores the create argument and thus is fine with the new version, ocfs2 only errors out if create were ever set, and we can remove this dead code now, the block device code only ever uses create for an error message if we are fully beyond the device which can never happen, and last but not least XFS will need the new behavour for writes. Now we can replace the lock_type variable with a flags one, where no flag means the DIO_NO_LOCKING behaviour and DIO_LOCKING is kept as the first flag. Separate out the check for not allowing to fill holes into a separate flag, although for now both flags always get set at the same time. Also revamp the documentation of the locking scheme to actually make sense. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Christoph Hellwig Cc: Dave Chinner Cc: Badari Pulavarty Cc: Jeff Moyer Cc: Jens Axboe Cc: Zach Brown Cc: Al Viro Cc: Alex Elder Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/xfs/linux-2.6/xfs_aops.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-) (limited to 'fs/xfs') diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c index d798c54296e..66abe36c121 100644 --- a/fs/xfs/linux-2.6/xfs_aops.c +++ b/fs/xfs/linux-2.6/xfs_aops.c @@ -1474,19 +1474,13 @@ xfs_vm_direct_IO( bdev = xfs_find_bdev_for_inode(XFS_I(inode)); - if (rw == WRITE) { - iocb->private = xfs_alloc_ioend(inode, IOMAP_UNWRITTEN); - ret = blockdev_direct_IO_own_locking(rw, iocb, inode, - bdev, iov, offset, nr_segs, - xfs_get_blocks_direct, - xfs_end_io_direct); - } else { - iocb->private = xfs_alloc_ioend(inode, IOMAP_READ); - ret = blockdev_direct_IO_no_locking(rw, iocb, inode, - bdev, iov, offset, nr_segs, - xfs_get_blocks_direct, - xfs_end_io_direct); - } + iocb->private = xfs_alloc_ioend(inode, rw == WRITE ? + IOMAP_UNWRITTEN : IOMAP_READ); + + ret = blockdev_direct_IO_no_locking(rw, iocb, inode, bdev, iov, + offset, nr_segs, + xfs_get_blocks_direct, + xfs_end_io_direct); if (unlikely(ret != -EIOCBQUEUED && iocb->private)) xfs_destroy_ioend(iocb->private); -- cgit v1.2.3-70-g09d2