[PATCH v2 tty-next 1/5] tty: Always handle NULL flag ptr

From: Peter Hurley
Date: Mon Dec 02 2013 - 13:56:37 EST


Most line disciplines already handle the undocumented NULL flag
ptr in their .receive_buf method; however, several don't.

Document the NULL flag ptr, and correct handling in the
N_MOUSE, N_GSM0710 and N_R394 line disciplines.

Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---

v2 - Uses 0 for no flags to serio layer per Dmitry.

drivers/input/serio/serport.c | 28 +++++++++++++++-------------
drivers/tty/n_gsm.c | 5 +++--
drivers/tty/n_r3964.c | 2 +-
include/linux/tty_ldisc.h | 6 ++++--
4 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/drivers/input/serio/serport.c b/drivers/input/serio/serport.c
index 8755f5f..0cb7ef5 100644
--- a/drivers/input/serio/serport.c
+++ b/drivers/input/serio/serport.c
@@ -124,7 +124,7 @@ static void serport_ldisc_receive(struct tty_struct *tty, const unsigned char *c
{
struct serport *serport = (struct serport*) tty->disc_data;
unsigned long flags;
- unsigned int ch_flags;
+ unsigned int ch_flags = 0;
int i;

spin_lock_irqsave(&serport->lock, flags);
@@ -133,18 +133,20 @@ static void serport_ldisc_receive(struct tty_struct *tty, const unsigned char *c
goto out;

for (i = 0; i < count; i++) {
- switch (fp[i]) {
- case TTY_FRAME:
- ch_flags = SERIO_FRAME;
- break;
-
- case TTY_PARITY:
- ch_flags = SERIO_PARITY;
- break;
-
- default:
- ch_flags = 0;
- break;
+ if (fp) {
+ switch (fp[i]) {
+ case TTY_FRAME:
+ ch_flags = SERIO_FRAME;
+ break;
+
+ case TTY_PARITY:
+ ch_flags = SERIO_PARITY;
+ break;
+
+ default:
+ ch_flags = 0;
+ break;
+ }
}

serio_interrupt(serport->serio, cp[i], ch_flags);
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index c0f76da..c09db11 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2269,14 +2269,15 @@ static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
char *f;
int i;
char buf[64];
- char flags;
+ char flags = TTY_NORMAL;

if (debug & 4)
print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
cp, count);

for (i = count, dp = cp, f = fp; i; i--, dp++) {
- flags = *f++;
+ if (f)
+ flags = *f++;
switch (flags) {
case TTY_NORMAL:
gsm->receive(gsm, *dp);
diff --git a/drivers/tty/n_r3964.c b/drivers/tty/n_r3964.c
index 1e64050..8b157d6 100644
--- a/drivers/tty/n_r3964.c
+++ b/drivers/tty/n_r3964.c
@@ -1244,7 +1244,7 @@ static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
{
struct r3964_info *pInfo = tty->disc_data;
const unsigned char *p;
- char *f, flags = 0;
+ char *f, flags = TTY_NORMAL;
int i;

for (i = count, p = cp, f = fp; i; i--, p++) {
diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h
index f15c898..b8347c2 100644
--- a/include/linux/tty_ldisc.h
+++ b/include/linux/tty_ldisc.h
@@ -84,7 +84,8 @@
* processing. <cp> is a pointer to the buffer of input
* character received by the device. <fp> is a pointer to a
* pointer of flag bytes which indicate whether a character was
- * received with a parity error, etc.
+ * received with a parity error, etc. <fp> may be NULL to indicate
+ * all data received is TTY_NORMAL.
*
* void (*write_wakeup)(struct tty_struct *);
*
@@ -118,7 +119,8 @@
* processing. <cp> is a pointer to the buffer of input
* character received by the device. <fp> is a pointer to a
* pointer of flag bytes which indicate whether a character was
- * received with a parity error, etc.
+ * received with a parity error, etc. <fp> may be NULL to indicate
+ * all data received is TTY_NORMAL.
* If assigned, prefer this function for automatic flow control.
*/

--
1.8.1.2

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