staging: gdm724x: Correction of variable usage after applying ALIGN()

Fix regression introduced by commit <29ef8a53542a>. After it writing
AT commands to /dev/GCT-ATM0 is unsuccessful (no echo, no response)
and dmesg show "gdmtty: invalid payload : 1 16 f011".

Before that commit value of dummy_cnt was only a padding size. After using
ALIGN() this value is increased by its first argument. So the following
usage of this variable needs correction.

Signed-off-by: Sławomir Demeszko <s.demeszko@wireless-instruments.com>
Cc: stable <stable@vger.kernel.org> # 3.14+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/gdm724x/gdm_mux.c b/drivers/staging/gdm724x/gdm_mux.c
index 8199b0a..1cf24e4 100644 (file)
--- a/drivers/staging/gdm724x/gdm_mux.c
+++ b/drivers/staging/gdm724x/gdm_mux.c
@@ -158,7 +158,7 @@ static int up_to_host(struct mux_rx *r)
        unsigned int start_flag;
        unsigned int payload_size;
        unsigned short packet_type;
-       int dummy_cnt;
+       int total_len;
        u32 packet_size_sum = r->offset;
        int index;
        int ret = TO_HOST_INVALID_PACKET;
@@ -176,10 +176,10 @@ static int up_to_host(struct mux_rx *r)
                        break;
                }
 
-               dummy_cnt = ALIGN(MUX_HEADER_SIZE + payload_size, 4);
+               total_len = ALIGN(MUX_HEADER_SIZE + payload_size, 4);
 
                if (len - packet_size_sum <
-                       MUX_HEADER_SIZE + payload_size + dummy_cnt) {
+                       total_len) {
                        pr_err("invalid payload : %d %d %04x\n",
                               payload_size, len, packet_type);
                        break;
@@ -202,7 +202,7 @@ static int up_to_host(struct mux_rx *r)
                        break;
                }
 
-               packet_size_sum += MUX_HEADER_SIZE + payload_size + dummy_cnt;
+               packet_size_sum += total_len;
                if (len - packet_size_sum <= MUX_HEADER_SIZE + 2) {
                        ret = r->callback(NULL,
                                        0,
@@ -361,7 +361,6 @@ static int gdm_mux_send(void *priv_dev, void *data, int len, int tty_index,
        struct mux_pkt_header *mux_header;
        struct mux_tx *t = NULL;
        static u32 seq_num = 1;
-       int dummy_cnt;
        int total_len;
        int ret;
        unsigned long flags;
@@ -374,9 +373,7 @@ static int gdm_mux_send(void *priv_dev, void *data, int len, int tty_index,
 
        spin_lock_irqsave(&mux_dev->write_lock, flags);
 
-       dummy_cnt = ALIGN(MUX_HEADER_SIZE + len, 4);
-
-       total_len = len + MUX_HEADER_SIZE + dummy_cnt;
+       total_len = ALIGN(MUX_HEADER_SIZE + len, 4);
 
        t = alloc_mux_tx(total_len);
        if (!t) {
@@ -392,7 +389,8 @@ static int gdm_mux_send(void *priv_dev, void *data, int len, int tty_index,
        mux_header->packet_type = __cpu_to_le16(packet_type[tty_index]);
 
        memcpy(t->buf+MUX_HEADER_SIZE, data, len);
-       memset(t->buf+MUX_HEADER_SIZE+len, 0, dummy_cnt);
+       memset(t->buf+MUX_HEADER_SIZE+len, 0, total_len - MUX_HEADER_SIZE -
+              len);
 
        t->len = total_len;
        t->callback = cb;