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Commit 28c0447d authored by Jiri Slaby's avatar Jiri Slaby Committed by Greg Kroah-Hartman
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TTY: hvsi, sanitize uses of tty 



- use tty, not hp->tty wherever possible
- pass tty down to some functions and go to step one
- do not defer tty_hangup calls -- it is as simple as schedule_work,
  so might be called with hp->lock held
- do not defer tty buffer flips -- since the driver does not use
  low_latency (it cannot actually), the flip is a simple tail move
  plus schedule_work. It will make our life easier in the next patch.

Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d73a4e79

drivers/tty/hvc/hvsi.c

+30 −58
Original line number Diff line number Diff line
@@ -237,7 +237,7 @@ static int hvsi_read(struct hvsi_struct *hp, char *buf, int count) 
}



static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,

	struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)

	struct tty_struct *tty, struct hvsi_struct **to_handshake)

{

	struct hvsi_control *header = (struct hvsi_control *)packet;
@@ -247,9 +247,8 @@ static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet, 
				/* CD went away; no more connection */

				pr_debug("hvsi%i: CD dropped\n", hp->index);

				hp->mctrl &= TIOCM_CD;

				/* If userland hasn't done an open(2) yet, hp->tty is NULL. */

				if (hp->tty && !C_CLOCAL(hp->tty))

					*to_hangup = hp->tty;

				if (tty && !C_CLOCAL(tty))

					tty_hangup(tty);

			}

			break;

		case VSV_CLOSE_PROTOCOL:
@@ -331,7 +330,8 @@ static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet) 
	}

}



static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)

static void hvsi_insert_chars(struct hvsi_struct *hp, struct tty_struct *tty,

		const char *buf, int len)

{

	int i;
@@ -347,7 +347,7 @@ static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len) 
			continue;

		}

#endif /* CONFIG_MAGIC_SYSRQ */

		tty_insert_flip_char(hp->tty, c, 0);

		tty_insert_flip_char(tty, c, 0);

	}

}
@@ -360,7 +360,7 @@ static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len) 
 * revisited.

 */

#define TTY_THRESHOLD_THROTTLE 128

static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,

static bool hvsi_recv_data(struct hvsi_struct *hp, struct tty_struct *tty,

		const uint8_t *packet)

{

	const struct hvsi_header *header = (const struct hvsi_header *)packet;
@@ -371,14 +371,14 @@ static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp, 
	pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);



	if (datalen == 0)

		return NULL;

		return false;



	if (overflow > 0) {

		pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __func__);

		datalen = TTY_THRESHOLD_THROTTLE;

	}



	hvsi_insert_chars(hp, data, datalen);

	hvsi_insert_chars(hp, tty, data, datalen);



	if (overflow > 0) {

		/*
@@ -390,7 +390,7 @@ static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp, 
		hp->n_throttle = overflow;

	}



	return hp->tty;

	return true;

}



/*
@@ -399,14 +399,13 @@ static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp, 
 * machine during console handshaking (in which case tty = NULL and we ignore

 * incoming data).

 */

static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,

		struct tty_struct **hangup, struct hvsi_struct **handshake)

static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct *tty,

		struct hvsi_struct **handshake)

{

	uint8_t *packet = hp->inbuf;

	int chunklen;

	bool flip = false;



	*flip = NULL;

	*hangup = NULL;

	*handshake = NULL;



	chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
@@ -440,12 +439,12 @@ static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip, 
			case VS_DATA_PACKET_HEADER:

				if (!is_open(hp))

					break;

				if (hp->tty == NULL)

				if (tty == NULL)

					break; /* no tty buffer to put data in */

				*flip = hvsi_recv_data(hp, packet);

				flip = hvsi_recv_data(hp, tty, packet);

				break;

			case VS_CONTROL_PACKET_HEADER:

				hvsi_recv_control(hp, packet, hangup, handshake);

				hvsi_recv_control(hp, packet, tty, handshake);

				break;

			case VS_QUERY_RESPONSE_PACKET_HEADER:

				hvsi_recv_response(hp, packet);
@@ -462,28 +461,26 @@ static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip, 


		packet += len_packet(packet);



		if (*hangup || *handshake) {

			pr_debug("%s: hangup or handshake\n", __func__);

			/*

			 * we need to send the hangup now before receiving any more data.

			 * If we get "data, hangup, data", we can't deliver the second

			 * data before the hangup.

			 */

		if (*handshake) {

			pr_debug("%s: handshake\n", __func__);

			break;

		}

	}



	compact_inbuf(hp, packet);



	if (flip)

		tty_flip_buffer_push(tty);



	return 1;

}



static void hvsi_send_overflow(struct hvsi_struct *hp)

static void hvsi_send_overflow(struct hvsi_struct *hp, struct tty_struct *tty)

{

	pr_debug("%s: delivering %i bytes overflow\n", __func__,

			hp->n_throttle);



	hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);

	hvsi_insert_chars(hp, tty, hp->throttle_buf, hp->n_throttle);

	hp->n_throttle = 0;

}
@@ -494,8 +491,6 @@ static void hvsi_send_overflow(struct hvsi_struct *hp) 
static irqreturn_t hvsi_interrupt(int irq, void *arg)

{

	struct hvsi_struct *hp = (struct hvsi_struct *)arg;

	struct tty_struct *flip;

	struct tty_struct *hangup;

	struct hvsi_struct *handshake;

	unsigned long flags;

	int again = 1;
@@ -504,25 +499,9 @@ static irqreturn_t hvsi_interrupt(int irq, void *arg) 


	while (again) {

		spin_lock_irqsave(&hp->lock, flags);

		again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);

		again = hvsi_load_chunk(hp, hp->tty, &handshake);

		spin_unlock_irqrestore(&hp->lock, flags);



		/*

		 * we have to call tty_flip_buffer_push() and tty_hangup() outside our

		 * spinlock. But we also have to keep going until we've read all the

		 * available data.

		 */



		if (flip) {

			/* there was data put in the tty flip buffer */

			tty_flip_buffer_push(flip);

			flip = NULL;

		}



		if (hangup) {

			tty_hangup(hangup);

		}



		if (handshake) {

			pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);

			schedule_work(&handshake->handshaker);
@@ -534,15 +513,11 @@ static irqreturn_t hvsi_interrupt(int irq, void *arg) 
			&& (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {

		/* we weren't hung up and we weren't throttled, so we can deliver the

		 * rest now */

		flip = hp->tty;

		hvsi_send_overflow(hp);

		hvsi_send_overflow(hp, hp->tty);

		tty_flip_buffer_push(hp->tty);

	}

	spin_unlock_irqrestore(&hp->lock, flags);



	if (flip) {

		tty_flip_buffer_push(flip);

	}



	return IRQ_HANDLED;

}
@@ -966,8 +941,8 @@ static int hvsi_write(struct tty_struct *tty, 
	 * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls

	 * will see there is no room in outbuf and return.

	 */

	while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {

		int chunksize = min(count, hvsi_write_room(hp->tty));

	while ((count > 0) && (hvsi_write_room(tty) > 0)) {

		int chunksize = min(count, hvsi_write_room(tty));



		BUG_ON(hp->n_outbuf < 0);

		memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
@@ -1014,19 +989,16 @@ static void hvsi_unthrottle(struct tty_struct *tty) 
{

	struct hvsi_struct *hp = tty->driver_data;

	unsigned long flags;

	int shouldflip = 0;



	pr_debug("%s\n", __func__);



	spin_lock_irqsave(&hp->lock, flags);

	if (hp->n_throttle) {

		hvsi_send_overflow(hp);

		shouldflip = 1;

		hvsi_send_overflow(hp, tty);

		tty_flip_buffer_push(tty);

	}

	spin_unlock_irqrestore(&hp->lock, flags);



	if (shouldflip)

		tty_flip_buffer_push(hp->tty);



	h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);

}