From: Daniel Starke <daniel.starke@xxxxxxxxxxx> Replace the use of gsm_read_ea() with gsm_read_ea_val() where applicable to improve code readability and avoid errors like in the past. Reported-by: kernel test robot <lkp@xxxxxxxxx> Signed-off-by: Daniel Starke <daniel.starke@xxxxxxxxxxx> --- drivers/tty/n_gsm.c | 99 +++++++++++++++++++++++---------------------- 1 file changed, 51 insertions(+), 48 deletions(-) Changes since v1: Fixed use of wrong variable in debug output within gsm_dlci_data(). Link: https://lore.kernel.org/all/202208222147.WfFRmf1r-lkp@xxxxxxxxx/ diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index ed399d57b197..9535e84f3063 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1418,18 +1418,13 @@ static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen) unsigned int modem = 0; struct gsm_dlci *dlci; int len = clen; - int slen; + int cl = clen; const u8 *dp = data; struct tty_struct *tty; - while (gsm_read_ea(&addr, *dp++) == 0) { - len--; - if (len == 0) - return; - } - /* Must be at least one byte following the EA */ - len--; - if (len <= 0) + len = gsm_read_ea_val(&addr, data, cl); + + if (len < 1) return; addr >>= 1; @@ -1438,15 +1433,21 @@ static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen) return; dlci = gsm->dlci[addr]; - slen = len; - while (gsm_read_ea(&modem, *dp++) == 0) { - len--; - if (len == 0) - return; - } - len--; + /* Must be at least one byte following the EA */ + if ((cl - len) < 1) + return; + + dp += len; + cl -= len; + + /* get the modem status */ + len = gsm_read_ea_val(&modem, dp, cl); + + if (len < 1) + return; + tty = tty_port_tty_get(&dlci->port); - gsm_process_modem(tty, dlci, modem, slen - len); + gsm_process_modem(tty, dlci, modem, cl); if (tty) { tty_wakeup(tty); tty_kref_put(tty); @@ -1921,11 +1922,10 @@ static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen) struct tty_port *port = &dlci->port; struct tty_struct *tty; unsigned int modem = 0; - int len = clen; - int slen = 0; + int len; if (debug & 16) - pr_debug("%d bytes for tty\n", len); + pr_debug("%d bytes for tty\n", clen); switch (dlci->adaption) { /* Unsupported types */ case 4: /* Packetised interruptible data */ @@ -1933,24 +1933,22 @@ static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen) case 3: /* Packetised uininterruptible voice/data */ break; case 2: /* Asynchronous serial with line state in each frame */ - while (gsm_read_ea(&modem, *data++) == 0) { - len--; - slen++; - if (len == 0) - return; - } - len--; - slen++; + len = gsm_read_ea_val(&modem, data, clen); + if (len < 1) + return; tty = tty_port_tty_get(port); if (tty) { - gsm_process_modem(tty, dlci, modem, slen); + gsm_process_modem(tty, dlci, modem, len); tty_wakeup(tty); tty_kref_put(tty); } + /* Skip processed modem data */ + data += len; + clen -= len; fallthrough; case 1: /* Line state will go via DLCI 0 controls only */ default: - tty_insert_flip_string(port, data, len); + tty_insert_flip_string(port, data, clen); tty_flip_buffer_push(port); } } @@ -1971,24 +1969,29 @@ static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len) { /* See what command is involved */ unsigned int command = 0; - while (len-- > 0) { - if (gsm_read_ea(&command, *data++) == 1) { - int clen = *data++; - len--; - /* FIXME: this is properly an EA */ - clen >>= 1; - /* Malformed command ? */ - if (clen > len) - return; - if (command & 1) - gsm_control_message(dlci->gsm, command, - data, clen); - else - gsm_control_response(dlci->gsm, command, - data, clen); - return; - } - } + const u8 *dp = data; + int clen = 0; + int dlen; + + /* read the command */ + dlen = gsm_read_ea_val(&command, dp, len); + len -= dlen; + dp += dlen; + + /* read any control data */ + dlen = gsm_read_ea_val(&clen, dp, len); + len -= dlen; + dp += dlen; + + /* Malformed command? */ + if (clen > len) + return; + + if (command & 1) + gsm_control_message(dlci->gsm, command, dp, clen); + else + gsm_control_response(dlci->gsm, command, dp, clen); + return; } /** -- 2.34.1
