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/ext4/file.c b/fs/ext4/file.c
index ac0e11b..b25c1f8 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -74,7 +74,7 @@ static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
return generic_file_read_iter(iocb, to);
}
- ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0);
+ ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0, 0);
inode_unlock_shared(inode);
file_accessed(iocb->ki_filp);
@@ -566,7 +566,8 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (ilock_shared)
iomap_ops = &ext4_iomap_overwrite_ops;
ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
- (unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0);
+ (unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0,
+ 0);
if (ret == -ENOTBLK)
ret = 0;