tty: ehv_bytecha: use memcpy_and_pad() in local_ev_byte_channel_send()

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
Link: https://lore.kernel.org/r/20231121092258.9334-8-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/ehv_bytechan.c b/drivers/tty/ehv_bytechan.c
index a067628e01c81843b6b68fbe03c169da6397f774..cc9f4338da601cf61c7fe51119aaceaa0c567206 100644 (file)
--- 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);