powerpc/powernv: opal_put_chars partial write fix

[ 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 65c79ecf5a4d685c3c2d5035a18b196bb9664f63..c8a743af6bf507d2a0f2d63e34bb20234a275d83 100644 (file)
--- 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 != OPAL_SUCCESS && rc != OPAL_BUSY &&
                    rc != OPAL_BUSY_EVENT) {
-                       written = total_len;
+                       written += total_len;
                        break;
                }
                if (rc == OPAL_SUCCESS) {