On 4.05.22 г. 19:23 ч., Christoph Hellwig wrote:
Allow the file system to keep state for all iterations. For now only
wire it up for direct I/O as there is an immediate need for it there.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/iomap/direct-io.c | 8 ++++++++
include/linux/iomap.h | 1 +
2 files changed, 9 insertions(+)
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 15929690d89e3..355abe2eacc6a 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -520,6 +520,14 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
dio->submit.waiter = current;
dio->submit.poll_bio = NULL;
+ /*
+ * Transfer the private data that was passed by the caller to the
+ * iomap_iter, and clear it in the iocb, as iocb->private will be
+ * used for polled bio completion later.
+ */
+ iomi.private = iocb->private;
+ WRITE_ONCE(iocb->private, NULL);
nit: Why use WRITE_ONCE here? Generaly when it's used it will suggest to
the reader something funny is going on with accessing that variable
without holding a particular lock?
+
if (iov_iter_rw(iter) == READ) {
if (iomi.pos >= dio->i_size)
goto out_free_dio;
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index a5483020dad41..109c055865f73 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -188,6 +188,7 @@ struct iomap_iter {
unsigned flags;
struct iomap iomap;
struct iomap srcmap;
+ void *private;
};
int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops);
