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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Andreas Gruenbacher <agruenba@redhat.com>,
        "Darrick J. Wong" <djwong@kernel.org>,
        Christoph Hellwig <hch@lst.de>,
        Anand Jain <anand.jain@oracle.com>
Subject: [PATCH 5.15 24/33] iomap: Fix iomap_dio_rw return value for user copies
Date:   Fri, 29 Apr 2022 12:42:11 +0200
Message-Id: <20220429104053.039706422@linuxfoundation.org>
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From: Andreas Gruenbacher <agruenba@redhat.com>

commit 42c498c18a94eed79896c50871889af52fa0822e upstream

When a user copy fails in one of the helpers of iomap_dio_rw, fail with
-EFAULT instead of returning 0.  This matches what iomap_dio_bio_actor
returns when it gets an -EFAULT from bio_iov_iter_get_pages.  With these
changes, iomap_dio_actor now consistently fails with -EFAULT when a user
page cannot be faulted in.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/iomap/direct-io.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -371,6 +371,8 @@ static loff_t iomap_dio_hole_iter(const
 	loff_t length = iov_iter_zero(iomap_length(iter), dio->submit.iter);
 
 	dio->size += length;
+	if (!length)
+		return -EFAULT;
 	return length;
 }
 
@@ -402,6 +404,8 @@ static loff_t iomap_dio_inline_iter(cons
 		copied = copy_to_iter(inline_data, length, iter);
 	}
 	dio->size += copied;
+	if (!copied)
+		return -EFAULT;
 	return copied;
 }