From b1c43f82c5aa265442f82dba31ce985ebb7aa71c Mon Sep 17 00:00:00 2001 From: Felipe Balbi Date: Mon, 21 Mar 2011 12:25:08 +0200 Subject: tty: make receive_buf() return the amout of bytes received it makes it simpler to keep track of the amount of bytes received and simplifies how flush_to_ldisc counts the remaining bytes. It also fixes a bug of lost bytes on n_tty when flushing too many bytes via the USB serial gadget driver. Tested-by: Stefan Bigler Tested-by: Toby Gray Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/net/ppp_async.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers/net/ppp_async.c') diff --git a/drivers/net/ppp_async.c b/drivers/net/ppp_async.c index a1b82c9c67d2..53872d7d7382 100644 --- a/drivers/net/ppp_async.c +++ b/drivers/net/ppp_async.c @@ -340,7 +340,7 @@ ppp_asynctty_poll(struct tty_struct *tty, struct file *file, poll_table *wait) } /* May sleep, don't call from interrupt level or with interrupts disabled */ -static void +static unsigned int ppp_asynctty_receive(struct tty_struct *tty, const unsigned char *buf, char *cflags, int count) { @@ -348,7 +348,7 @@ ppp_asynctty_receive(struct tty_struct *tty, const unsigned char *buf, unsigned long flags; if (!ap) - return; + return -ENODEV; spin_lock_irqsave(&ap->recv_lock, flags); ppp_async_input(ap, buf, cflags, count); spin_unlock_irqrestore(&ap->recv_lock, flags); @@ -356,6 +356,8 @@ ppp_asynctty_receive(struct tty_struct *tty, const unsigned char *buf, tasklet_schedule(&ap->tsk); ap_put(ap); tty_unthrottle(tty); + + return count; } static void -- cgit v1.2.3 From 55db4c64eddf37e31279ec15fe90314713bc9cfa Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 4 Jun 2011 06:33:24 +0900 Subject: Revert "tty: make receive_buf() return the amout of bytes received" This reverts commit b1c43f82c5aa265442f82dba31ce985ebb7aa71c. It was broken in so many ways, and results in random odd pty issues. It re-introduced the buggy schedule_work() in flush_to_ldisc() that can cause endless work-loops (see commit a5660b41af6a: "tty: fix endless work loop when the buffer fills up"). It also used an "unsigned int" return value fo the ->receive_buf() function, but then made multiple functions return a negative error code, and didn't actually check for the error in the caller. And it didn't actually work at all. BenH bisected down odd tty behavior to it: "It looks like the patch is causing some major malfunctions of the X server for me, possibly related to PTYs. For example, cat'ing a large file in a gnome terminal hangs the kernel for -minutes- in a loop of what looks like flush_to_ldisc/workqueue code, (some ftrace data in the quoted bits further down). ... Some more data: It -looks- like what happens is that the flush_to_ldisc work queue entry constantly re-queues itself (because the PTY is full ?) and the workqueue thread will basically loop forver calling it without ever scheduling, thus starving the consumer process that could have emptied the PTY." which is pretty much exactly the problem we fixed in a5660b41af6a. Milton Miller pointed out the 'unsigned int' issue. Reported-by: Benjamin Herrenschmidt Reported-by: Milton Miller Cc: Stefan Bigler Cc: Toby Gray Cc: Felipe Balbi Cc: Greg Kroah-Hartman Cc: Alan Cox Signed-off-by: Linus Torvalds --- drivers/net/ppp_async.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'drivers/net/ppp_async.c') diff --git a/drivers/net/ppp_async.c b/drivers/net/ppp_async.c index 53872d7d7382..a1b82c9c67d2 100644 --- a/drivers/net/ppp_async.c +++ b/drivers/net/ppp_async.c @@ -340,7 +340,7 @@ ppp_asynctty_poll(struct tty_struct *tty, struct file *file, poll_table *wait) } /* May sleep, don't call from interrupt level or with interrupts disabled */ -static unsigned int +static void ppp_asynctty_receive(struct tty_struct *tty, const unsigned char *buf, char *cflags, int count) { @@ -348,7 +348,7 @@ ppp_asynctty_receive(struct tty_struct *tty, const unsigned char *buf, unsigned long flags; if (!ap) - return -ENODEV; + return; spin_lock_irqsave(&ap->recv_lock, flags); ppp_async_input(ap, buf, cflags, count); spin_unlock_irqrestore(&ap->recv_lock, flags); @@ -356,8 +356,6 @@ ppp_asynctty_receive(struct tty_struct *tty, const unsigned char *buf, tasklet_schedule(&ap->tsk); ap_put(ap); tty_unthrottle(tty); - - return count; } static void -- cgit v1.2.3 From e6539e2b7aee117619153daaf61566dba1e04205 Mon Sep 17 00:00:00 2001 From: Changli Gao Date: Tue, 14 Jun 2011 21:58:13 +0000 Subject: ppp: use PPP_TRANS instead of the magic number 0x20 Signed-off-by: Changli Gao Signed-off-by: David S. Miller --- drivers/net/ppp_async.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/net/ppp_async.c') diff --git a/drivers/net/ppp_async.c b/drivers/net/ppp_async.c index a1b82c9c67d2..c554a397e558 100644 --- a/drivers/net/ppp_async.c +++ b/drivers/net/ppp_async.c @@ -523,7 +523,7 @@ static void ppp_async_process(unsigned long arg) #define PUT_BYTE(ap, buf, c, islcp) do { \ if ((islcp && c < 0x20) || (ap->xaccm[c >> 5] & (1 << (c & 0x1f)))) {\ *buf++ = PPP_ESCAPE; \ - *buf++ = c ^ 0x20; \ + *buf++ = c ^ PPP_TRANS; \ } else \ *buf++ = c; \ } while (0) @@ -896,7 +896,7 @@ ppp_async_input(struct asyncppp *ap, const unsigned char *buf, sp = skb_put(skb, n); memcpy(sp, buf, n); if (ap->state & SC_ESCAPE) { - sp[0] ^= 0x20; + sp[0] ^= PPP_TRANS; ap->state &= ~SC_ESCAPE; } } -- cgit v1.2.3