iomap: Add done_before argument to iomap_dio_rw
Add a done_before argument to iomap_dio_rw that indicates how much of
the request has already been transferred. When the request succeeds, we
report that done_before additional bytes were tranferred. This is
useful for finishing a request asynchronously when part of the request
has already been completed synchronously.
We'll use that to allow iomap_dio_rw to be used with page faults
disabled: when a page fault occurs while submitting a request, we
synchronously complete the part of the request that has already been
submitted. The caller can then take care of the page fault and call
iomap_dio_rw again for the rest of the request, passing in the number of
bytes already tranferred.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index f37211d..9d41b28 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1957,7 +1957,7 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
}
dio = __iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops, &btrfs_dio_ops,
- 0);
+ 0, 0);
btrfs_inode_unlock(inode, ilock_flags);
@@ -3658,7 +3658,8 @@ static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
return 0;
btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
- ret = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dio_ops, 0);
+ ret = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dio_ops,
+ 0, 0);
btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
return ret;
}
