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From:   Sasha Levin <Alexander.Levin@microsoft.com>
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        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Nicholas Piggin <npiggin@gmail.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL 4.18 55/88] powerpc/powernv: opal_put_chars partial
 write fix
Thread-Topic: [PATCH AUTOSEL 4.18 55/88] powerpc/powernv: opal_put_chars
 partial write fix
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Date:   Fri, 7 Sep 2018 00:36:32 +0000
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From: Nicholas Piggin <npiggin@gmail.com>

[ Upstream commit bd90284cc6c1c9e8e48c8eadd0c79574fcce0b81 ]

The intention here is to consume and discard the remaining buffer
upon error. This works if there has not been a previous partial write.
If there has been, then total_len is no longer total number of bytes
to copy. total_len is always "bytes left to copy", so it should be
added to written bytes.

This code may not be exercised any more if partial writes will not be
hit, but this is a small bugfix before a larger change.

Reviewed-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 arch/powerpc/platforms/powernv/opal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms=
/powernv/opal.c
index 0d539c661748..371e33ecc547 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -388,7 +388,7 @@ int opal_put_chars(uint32_t vtermno, const char *data, =
int total_len)
 		/* Closed or other error drop */
 		if (rc !=3D OPAL_SUCCESS && rc !=3D OPAL_BUSY &&
 		    rc !=3D OPAL_BUSY_EVENT) {
-			written =3D total_len;
+			written +=3D total_len;
 			break;
 		}
 		if (rc =3D=3D OPAL_SUCCESS) {
--=20
2.17.1