From 28c0447d743ba94562f981bf09dda61bc4cc6f3b Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Mon, 2 Apr 2012 13:54:29 +0200 Subject: [PATCH] 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: Jiri Slaby Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/hvc/hvsi.c | 88 ++++++++++++++---------------------------- 1 file changed, 30 insertions(+), 58 deletions(-) diff --git a/drivers/tty/hvc/hvsi.c b/drivers/tty/hvc/hvsi.c index 113a09abcf7b..68b729b8d1eb 100644 --- a/drivers/tty/hvc/hvsi.c +++ b/drivers/tty/hvc/hvsi.c @@ -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); } -- 2.20.1