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From:   "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
To:     gregkh@linuxfoundation.org
Cc:     linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        "Jiri Slaby (SUSE)" <jirislaby@kernel.org>,
        Laurentiu Tudor <laurentiu.tudor@nxp.com>,
        linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 07/17] tty: ehv_bytecha: use memcpy_and_pad() in local_ev_byte_channel_send()
Date:   Tue, 21 Nov 2023 10:22:48 +0100
Message-ID: <20231121092258.9334-8-jirislaby@kernel.org>
In-Reply-To: <20231121092258.9334-1-jirislaby@kernel.org>
References: <20231121092258.9334-1-jirislaby@kernel.org>
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There is a helper for memcpy(buffer)+memset(the_rest). Use it for
simplicity.

And add a comment why we are doing the copy in the first place.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Cc: linuxppc-dev@lists.ozlabs.org
---
 drivers/tty/ehv_bytechan.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/ehv_bytechan.c b/drivers/tty/ehv_bytechan.c
index a067628e01c8..cc9f4338da60 100644
--- a/drivers/tty/ehv_bytechan.c
+++ b/drivers/tty/ehv_bytechan.c
@@ -143,9 +143,12 @@ static unsigned int local_ev_byte_channel_send(unsigned int handle,
 	char buffer[EV_BYTE_CHANNEL_MAX_BYTES];
 	unsigned int c = *count;
 
+	/*
+	 * ev_byte_channel_send() expects at least EV_BYTE_CHANNEL_MAX_BYTES
+	 * (16 B) in the buffer. Fake it using a local buffer if needed.
+	 */
 	if (c < sizeof(buffer)) {
-		memcpy(buffer, p, c);
-		memset(&buffer[c], 0, sizeof(buffer) - c);
+		memcpy_and_pad(buffer, sizeof(buffer), p, c, 0);
 		p = buffer;
 	}
 	return ev_byte_channel_send(handle, count, p);
-- 
2.42.1