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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Stefan Berger <stefanb@linux.ibm.com>,
        Jerry Snitselaar <jsnitsel@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 15/44] tpm/tpm_i2c_atmel: Return -E2BIG when the transfer is incomplete
Date:   Wed, 24 Apr 2019 19:09:53 +0200
Message-Id: <20190424170851.197513507@linuxfoundation.org>
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commit 442601e87a4769a8daba4976ec3afa5222ca211d upstream

Return -E2BIG when the transfer is incomplete. The upper layer does
not retry, so not doing that is incorrect behaviour.

Cc: stable@vger.kernel.org
Fixes: a2871c62e186 ("tpm: Add support for Atmel I2C TPMs")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/char/tpm/tpm_i2c_atmel.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm_i2c_atmel.c b/drivers/char/tpm/tpm_i2c_atmel.c
index 95ce2e9ccdc6..cc4e642d3180 100644
--- a/drivers/char/tpm/tpm_i2c_atmel.c
+++ b/drivers/char/tpm/tpm_i2c_atmel.c
@@ -65,7 +65,15 @@ static int i2c_atmel_send(struct tpm_chip *chip, u8 *buf, size_t len)
 	dev_dbg(&chip->dev,
 		"%s(buf=%*ph len=%0zx) -> sts=%d\n", __func__,
 		(int)min_t(size_t, 64, len), buf, len, status);
-	return status;
+
+	if (status < 0)
+		return status;
+
+	/* The upper layer does not support incomplete sends. */
+	if (status != len)
+		return -E2BIG;
+
+	return 0;
 }
 
 static int i2c_atmel_recv(struct tpm_chip *chip, u8 *buf, size_t count)
-- 
2.19.1