From 4fdccaa0d184c202f98d73b24e3ec8eeee88ab8d Mon Sep 17 00:00:00 2001
From: Andreas Gruenbacher <agruenba@redhat.com>
Date: Sat, 24 Jul 2021 12:26:41 +0200
Subject: 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>
---
 fs/gfs2/file.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'fs/gfs2')

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index d9126e3e6dd6..f772ee0fcae3 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -822,7 +822,7 @@ static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to,
 	if (ret)
 		goto out_uninit;
 
-	ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL, 0);
+	ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL, 0, 0);
 	gfs2_glock_dq(gh);
 out_uninit:
 	gfs2_holder_uninit(gh);
@@ -856,7 +856,7 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
 	if (offset + len > i_size_read(&ip->i_inode))
 		goto out;
 
-	ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL, 0);
+	ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL, 0, 0);
 	if (ret == -ENOTBLK)
 		ret = 0;
 out:
-- 
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