TTY loosing data with u_serial gadget
Subsystems (6)
Hi all
I'm facing a problem with TTY loosing data using u_serial gadget.
I have a MPC8247 based system running 2.6.33. Data transfer is done bidirectional to see the problem more often. I use tty in raw mode and do some delayed reads on the receiver side to stress the throttling / un-throttling.
I tracked down the problem and was able to see that n_tty_receive_buf() is not able to store all data in the read queue.
The function flush_to_ldisc() use the values of tty->receive_room to schedule_delayed_work()or to pass data to receive_buf() and finally n_tty_receive_buf(). Also the number of passed bytes rely on variable receive_room.
I added debug code to re-calculate the real free space.
left_space = N_TTY_BUF_SIZE - tty->read_cnt - 1;
Comparing receive_room and left_space showed in some cases big differences up to 1600 bytes. left_space was always smaller and sometimes zero.
receive_room is calculated in n_tty_set_room() without read locking. There are various "FIXME does n_tty_set_room need locking ?" My test showed, adding a read looking solves the problem.
I asked me why is the locking not done? How big is the risk for dead-locks? To minimize this risk, I reduced the changes to a minimum (see the patch below). The code in the patch only re-calculates the receive_room for raw mode right before it is used in flush_to_ldisc().
Can somebody give me an advice, what is the best way to solve this problem?
Thanks for your help.
Regards Stefan
From 91b04c875cecc890139ccdd101cfff6b02b5f22c Mon Sep 17 00:00:00 2001
From: Stefan Bigler <[email protected]>
Date: Wed, 16 Mar 2011 15:20:03 +0100
Subject: [PATCH 1/1] n_tty: fix race condition with receive_room
Do an additional update of receive_room with locking for raw tty. The n_tty_set_room is done without locking what is known as a potential problem.
In case of heavy load and raw tty and flush_to_ldisc() determine the number of char to send with receive_buf(). If there is not enough space available in receive_buf() the data is lost. This additional update of receive_room should reduce the risk of have invalid receive_room. It is not a clean fix but the risk of risk a dead-lock with clean protection is too high
--- drivers/char/tty_buffer.c | 16 ++++++++++++++++ 1 files changed, 16 insertions(+), 0 deletions(-)
drivers/char/tty_buffer.c +16 -0
@@ -431,6 +431,22 @@ static void flush_to_ldisc(struct work_struct *work)line discipline as we want to empty the queue */ if (test_bit (TTY_FLUSHPENDING , &tty->flags))break ; + +/* Take read_lock to update receive_room. +This avoids invalid free space information. +To limit the risk of introducing problems +only do it for raw tty */ +if (tty->raw) { +unsigned long flags_r; +spin_lock_irqsave (&tty->read_lock, + flags_r); + tty->receive_room = +N_TTY_BUF_SIZE - + tty->read_cnt -1 ; +spin_unlock_irqrestore (&tty->read_lock, + flags_r); + } +if (!tty->receive_room) {schedule_delayed_work (&tty->buf.work,1 );break ;
Signature · 1 line
1.7.0.5
Quoted 5 lines · Stefan Bigler
Hi all
I'm facing a problem with TTY loosing data using
u_serialgadget.I have a MPC8247 based system running 2.6.33.
Oh, that's an old kernel, lots of work on the tty layer has happened since then that would fix issues like this.
If you are stuck using this kernel, please go ask your vendor for support for it.
If not, can you try out 2.6.38 and let us, and the [email protected] list know if you still have problems with it?
thanks,
greg k-h
Hi Greg
Thanks for your quick answer. Meanwhile we ported our board to 2.6.38. We recognize the same problem again.
I had also a look at the relevant fixes, a lot is done but I could not find the required protection of the attribute receive_room.
I added a printk in case of failure were receive_room shows more space that is really available in the queue and also used.
The printk is attached below and also the log.
Regards
Stefan
Log:flush_to_ldisc, receive_room to small count=201, receive_room=287, real_room=0 flush_to_ldisc, receive_room to small count=225, receive_room=1031, real_room=0 flush_to_ldisc, receive_room to small count=33, receive_room=4095, real_room=0
drivers/tty/tty_buffer.c +15 -0
@@ -442,6 +442,21 @@ static void flush_to_ldisc(struct work_struct *work)line discipline as we want to empty the queue */ if (test_bit (TTY_FLUSHPENDING , &tty->flags))break ; + +/* add printk in case of inconsistante size */ +if (tty->raw) { +unsigned long flags_r; +int real_room; +spin_lock_irqsave (&tty->read_lock, flags_r); + real_room =N_TTY_BUF_SIZE -tty->read_cnt -1 ; +if (real_room <min (count, tty->receive_room)) { +printk (KERN_ERR "flush_to_ldisc, receive_room to small count=%d," +" receive_room=%d, real_room=%d\n" , + count, tty->receive_room, real_room); + } +spin_unlock_irqrestore (&tty->read_lock, flags_r); + } +if (!tty->receive_room || seen_tail) {schedule_delayed_work (&tty->buf.work,1 );break ;
Am 03/17/2011 01:04 AM, wrote Greg KH:
Quoted 18 lines · Stefan Bigler
Quoted 5 lines
Hi all
I'm facing a problem with TTY loosing data using
u_serialgadget.I have a MPC8247 based system running 2.6.33.
Oh, that's an old kernel, lots of work on the tty layer has happened since then that would fix issues like this.
If you are stuck using this kernel, please go ask your vendor for support for it.
If not, can you try out 2.6.38 and let us, and the [email protected] list know if you still have problems with it?
thanks,
greg k-h
Hi,
(please don't top-post)
Quoted 14 lines · Stefan Bigler
Thanks for your quick answer. Meanwhile we ported our board to 2.6.38. We recognize the same problem again.
I had also a look at the relevant fixes, a lot is done but I could not find the required protection of the attributereceive_room.I added a printk in case of failure were
receive_roomshows more space that is really available in the queue and also used.The printk is attached below and also the log.
Regards
Stefan
Quoted 7 lines
Log:
flush_to_ldisc,receive_roomto small count=201, receive_room=287, real_room=0flush_to_ldisc,receive_roomto small count=225, receive_room=1031, real_room=0flush_to_ldisc,receive_roomto small count=33, receive_room=4095, real_room=0
I had the same problem while I was working at Nokia developing the N900. I even sent a patch (twice) with Alan Cox on the loop but nothing has happened. The patch might still be floating on the archives but essentially it would make ->receive_buf() return the amount of received bytes (as IMHO it should be done).
Signature · 1 line
balbi
Quoted 3 lines
I had the same problem while I was working at Nokia developing the N900. I even sent a patch (twice) with Alan Cox on the loop but nothing has happened.
http://lkml.indiana.edu/hypermail/linux/kernel/0910.0/02347.html
is I assume the thread you are talking about - which ground to a halt without actually figuring out what you were seeing and what was really going on.
http://permalink.gmane.org/gmane.linux.usb.general/28976
would be the second generation one which was somewhat longer after I ceased to be tty maintainer so I can't really say it never got upstream.
I still think its the right thing to do, so perhaps it's worth reposting it, especially if it fixes this case too.
Alan
Quoted 10 lines · Alan Cox
Quoted 3 lines
I had the same problem while I was working at Nokia developing the N900. I even sent a patch (twice) with Alan Cox on the loop but nothing has happened.
http://lkml.indiana.edu/hypermail/linux/kernel/0910.0/02347.html
is I assume the thread you are talking about - which ground to a halt without actually figuring out what you were seeing and what was really going on.
Quoted 7 lines
http://permalink.gmane.org/gmane.linux.usb.general/28976
would be the second generation one which was somewhat longer after I ceased to be tty maintainer so I can't really say it never got upstream.
I still think its the right thing to do, so perhaps it's worth reposting it, especially if it fixes this case too.
Ok, I'll update that patch and re-send. I'll compile test on x86 and boot test on an ARM box, so it would be cool to have Acks from several people before applying, just in case.
Signature · 1 line
balbi
Quoted 16 lines · Felipe Balbi
Quoted 15 lines · Alan Cox
Quoted 3 lines
I had the same problem while I was working at Nokia developing the N900. I even sent a patch (twice) with Alan Cox on the loop but nothing has happened.
http://lkml.indiana.edu/hypermail/linux/kernel/0910.0/02347.html
is I assume the thread you are talking about - which ground to a halt without actually figuring out what you were seeing and what was really going on.
http://permalink.gmane.org/gmane.linux.usb.general/28976
would be the second generation one which was somewhat longer after I ceased to be tty maintainer so I can't really say it never got upstream.
Quoted 6 lines
Quoted 2 lines
I still think its the right thing to do, so perhaps it's worth reposting it, especially if it fixes this case too.
Ok, I'll update that patch and re-send. I'll compile test on x86 and boot test on an ARM box, so it would be cool to have Acks from several people before applying, just in case.
Patch attached, please give it a good round of test as I don't have how to exercise all line disciplines. I ran 100 randconfigs over night and no warnings or erros on that area, at least not that I could see (so many warning while compiling the kernel :-( )
Signature · 1 line
balbi
Quoted 1 line
From
3d099a44deb26c10e0e51be0432d6dcc107d3358Mon Sep 17 00:00:00 2001
From: Felipe Balbi <[email protected]>
Date: Mon, 21 Mar 2011 12:25:08 +0200
Subject: [PATCH] ty: make receive_buf() return the amout of bytes received
Organization: Texas Instruments\n
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.
--- drivers/bluetooth/hci_ldisc.c | 12 +++++-- drivers/input/serio/serport.c | 10 +++++- drivers/isdn/gigaset/ser-gigaset.c | 8 +++-- drivers/misc/ti-st/st_core.c | 6 ++- drivers/net/caif/caif_serial.c | 6 ++- drivers/net/can/slcan.c | 9 ++++-- drivers/net/hamradio/6pack.c | 8 +++-- drivers/net/hamradio/mkiss.c | 11 ++++-- drivers/net/irda/irtty-sir.c | 16 ++++++---- drivers/net/ppp_async.c | 6 ++- drivers/net/ppp_synctty.c | 6 ++- drivers/net/slip.c | 11 ++++-- drivers/net/wan/x25_asy.c | 7 +++- drivers/tty/n_gsm.c | 6 ++- drivers/tty/n_hdlc.c | 18 ++++++----- drivers/tty/n_r3964.c | 10 ++++-- drivers/tty/n_tty.c | 54 ++++++++--------------------------- include/linux/tty_ldisc.h | 9 +++-- 18 files changed, 114 insertions(+), 99 deletions(-)
drivers/bluetooth/hci_ldisc.c +8 -4
@@ -357,22 +357,26 @@ static void hci_uart_tty_wakeup(struct tty_struct *tty)* * Return Value: None */ -static void hci_uart_tty_receive (struct tty_struct *tty,const u8 *data,char *flags,int count) +static unsigned int hci_uart_tty_receive (struct tty_struct *tty, +const u8 *data,char *flags,int count) {struct hci_uart *hu = (void *)tty->disc_data; +int received;if (!hu || tty != hu->tty) -return ; +return -ENODEV ;if (!test_bit (HCI_UART_PROTO_SET , &hu->flags)) -return ; +return -EINVAL ;spin_lock (&hu->rx_lock); - hu->proto->recv (hu, (void *) data, count); + received = hu->proto->recv (hu, (void *) data, count); hu->hdev->stat.byte_rx += count;spin_unlock (&hu->rx_lock);tty_unthrottle (tty); + +return received; }static int hci_uart_register_dev (struct hci_uart *hu)
drivers/input/serio/serport.c +8 -2
@@ -120,17 +120,21 @@ static void serport_ldisc_close(struct tty_struct *tty)* 'interrupt' routine. */ -static void serport_ldisc_receive (struct tty_struct *tty,const unsigned char *cp,char *fp,int count) +static unsigned int serport_ldisc_receive (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct serport *serport = (struct serport *) tty->disc_data;unsigned long flags;unsigned int ch_flags; +int ret =0 ;int i;spin_lock_irqsave (&serport->lock, flags); -if (!test_bit (SERPORT_ACTIVE , &serport->flags)) +if (!test_bit (SERPORT_ACTIVE , &serport->flags)) { + ret = -EINVAL ; goto out; + }for (i =0 ; i < count; i++) {switch (fp[i]) {
@@ -152,6 +156,8 @@ static void serport_ldisc_receive(struct tty_struct *tty, const unsigned char *c out:spin_unlock_irqrestore (&serport->lock, flags); + +return ret ==0 ? count : ret; }/*
drivers/isdn/gigaset/ser-gigaset.c +5 -3
@@ -674,7 +674,7 @@ gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,* cflags buffer containing error flags for received characters (ignored) * count number of received characters */ -static void +static unsigned int gigaset_tty_receive (struct tty_struct *tty,const unsigned char *buf,char *cflags,int count) {
@@ -683,12 +683,12 @@ gigaset_tty_receive(struct tty_struct *tty, const unsigned char *buf,struct inbuf_t *inbuf;if (!cs) -return ; +return -ENODEV ; inbuf = cs->inbuf;if (!inbuf) {dev_err (cs->dev,"%s: no inbuf\n" , __func__);cs_put (cs); -return ; +return -EINVAL ; } tail = inbuf->tail;
@@ -725,6 +725,8 @@ gigaset_tty_receive(struct tty_struct *tty, const unsigned char *buf,gig_dbg (DEBUG_INTR ,"%s-->BH" , __func__);gigaset_schedule_event (cs);cs_put (cs); + +return count; }/*
drivers/misc/ti-st/st_core.c +4 -2
@@ -866,8 +866,8 @@ static void st_tty_close(struct tty_struct *tty)pr_debug ("%s: done " , __func__); } -static void st_tty_receive (struct tty_struct *tty,const unsigned char *data, -char *tty_flags,int count) +static unsigned int st_tty_receive (struct tty_struct *tty, +const unsigned char *data,char *tty_flags,int count) {#ifdef VERBOSE
@@ -881,6 +881,8 @@ static void st_tty_receive(struct tty_struct *tty, const unsigned char *data,*/ st_recv (tty->disc_data, data, count);pr_debug ("done %s" , __func__); + +return count; }/* wake-up function called in from the TTY layer
drivers/net/caif/caif_serial.c +4 -2
@@ -167,8 +167,8 @@ static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)#endif -static void ldisc_receive (struct tty_struct *tty,const u8 *data, -char *flags,int count) +static unsigned int ldisc_receive (struct tty_struct *tty, +const u8 *data,char *flags,int count) {struct sk_buff *skb =NULL ;struct ser_device *ser;
@@ -215,6 +215,8 @@ static void ldisc_receive(struct tty_struct *tty, const u8 *data, }else ++ser->dev->stats.rx_dropped;update_tty_status (ser); + +return count; }static int handle_tx (struct ser_device *ser)
drivers/net/can/slcan.c +6 -3
@@ -425,16 +425,17 @@ static void slc_setup(struct net_device *dev)* in parallel */ -static void slcan_receive_buf (struct tty_struct *tty, +static unsigned int slcan_receive_buf (struct tty_struct *tty,const unsigned char *cp,char *fp,int count) {struct slcan *sl = (struct slcan *) tty->disc_data; +int bytes = count;if (!sl || sl->magic !=SLCAN_MAGIC || !netif_running (sl->dev)) -return ; +return -ENODEV ;/* Read the characters out of the buffer */ -while (count--) { +while (bytes--) {if (fp && *fp++) {if (!test_and_set_bit (SLF_ERROR , &sl->flags)) sl->dev->stats.rx_errors++;
@@ -443,6 +444,8 @@ static void slcan_receive_buf(struct tty_struct *tty, }slcan_unesc (sl, *cp++); } + +return count; }/************************************
drivers/net/hamradio/6pack.c +5 -3
@@ -456,7 +456,7 @@ out:* a block of 6pack data has been received, which can now be decapsulated * and sent on to some IP layer for further processing. */ -static void sixpack_receive_buf (struct tty_struct *tty, +static unsigned int sixpack_receive_buf (struct tty_struct *tty,const unsigned char *cp,char *fp,int count) {struct sixpack *sp;
@@ -464,11 +464,11 @@ static void sixpack_receive_buf(struct tty_struct *tty,int count1;if (!count) -return ; +return 0 ; sp =sp_get (tty);if (!sp) -return ; +return -ENODEV ;memcpy (buf, cp, count <sizeof (buf) ? count :sizeof (buf));
@@ -487,6 +487,8 @@ static void sixpack_receive_buf(struct tty_struct *tty,sp_put (sp);tty_unthrottle (tty); + +return count1; }/*
drivers/net/hamradio/mkiss.c +7 -4
@@ -923,13 +923,14 @@ static long mkiss_compat_ioctl(struct tty_struct *tty, struct file *file,* a block of data has been received, which can now be decapsulated * and sent on to the AX.25 layer for further processing. */ -static void mkiss_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int mkiss_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct mkiss *ax =mkiss_get (tty); +int bytes = count;if (!ax) -return ; +return -ENODEV ;/* * Argh! mtu change time! - costs us the packet part received
@@ -939,7 +940,7 @@ static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,ax_changedmtu (ax);/* Read the characters out of the buffer */ -while (count--) { +while (bytes--) {if (fp !=NULL && *fp++) {if (!test_and_set_bit (AXF_ERROR , &ax->flags)) ax->dev->stats.rx_errors++;
@@ -952,6 +953,8 @@ static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,mkiss_put (ax);tty_unthrottle (tty); + +return count; }/*
drivers/net/irda/irtty-sir.c +9 -7
@@ -216,23 +216,23 @@ static int irtty_do_write(struct sir_dev *dev, const unsigned char *ptr, size_t* usbserial: urb-complete-interrupt / softint */ -static void irtty_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int irtty_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct sir_dev *dev;struct sirtty_cb *priv = tty->disc_data;int i; - IRDA_ASSERT(priv != NULL, return;); - IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;); + IRDA_ASSERT(priv != NULL, return -ENODEV;); + IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -EINVAL;);if (unlikely (count==0 ))/* yes, this happens */ -return ; +return 0 ; dev = priv->dev;if (!dev) {IRDA_WARNING ("%s(), not ready yet!\n" , __func__); -return ; +return -ENODEV ; }for (i =0 ; i < count; i++) {
@@ -242,11 +242,13 @@ static void irtty_receive_buf(struct tty_struct *tty, const unsigned char *cp,if (fp && *fp++) {IRDA_DEBUG (0 ,"Framing or parity error!\n" );sirdev_receive (dev,NULL ,0 );/* notify sir_dev (updating stats) */ -return ; +return -EINVAL ; } }sirdev_receive (dev, cp, count); + +return count; }/*
drivers/net/ppp_async.c +4 -2
@@ -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
drivers/net/ppp_synctty.c +4 -2
@@ -381,7 +381,7 @@ ppp_sync_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_sync_receive (struct tty_struct *tty,const unsigned char *buf,char *cflags,int count) {
@@ -389,7 +389,7 @@ ppp_sync_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_sync_input (ap, buf, cflags, count);spin_unlock_irqrestore (&ap->recv_lock, flags);
@@ -397,6 +397,8 @@ ppp_sync_receive(struct tty_struct *tty, const unsigned char *buf,tasklet_schedule (&ap->tsk);sp_put (ap);tty_unthrottle (tty); + +return count; } static void
drivers/net/slip.c +7 -4
@@ -670,16 +670,17 @@ static void sl_setup(struct net_device *dev)* in parallel */ -static void slip_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int slip_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct slip *sl = tty->disc_data; +int bytes = count;if (!sl || sl->magic !=SLIP_MAGIC || !netif_running (sl->dev)) -return ; +return -ENODEV ;/* Read the characters out of the buffer */ -while (count--) { +while (bytes--) {if (fp && *fp++) {if (!test_and_set_bit (SLF_ERROR , &sl->flags)) sl->dev->stats.rx_errors++;
@@ -693,6 +694,8 @@ static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp,#endif slip_unesc (sl, *cp++); } + +return count; }/************************************
drivers/net/wan/x25_asy.c +5 -2
@@ -517,17 +517,18 @@ static int x25_asy_close(struct net_device *dev)* and sent on to some IP layer for further processing. */ -static void x25_asy_receive_buf (struct tty_struct *tty, +static unsigned int x25_asy_receive_buf (struct tty_struct *tty,const unsigned char *cp,char *fp,int count) {struct x25_asy *sl = tty->disc_data; +int bytes = count;if (!sl || sl->magic !=X25_ASY_MAGIC || !netif_running (sl->dev))return ;/* Read the characters out of the buffer */ -while (count--) { +while (bytes--) {if (fp && *fp++) {if (!test_and_set_bit (SLF_ERROR , &sl->flags)) sl->dev->stats.rx_errors++;
@@ -536,6 +537,8 @@ static void x25_asy_receive_buf(struct tty_struct *tty, }x25_asy_unesc (sl, *cp++); } + +return count; }/*
drivers/tty/n_gsm.c +4 -2
@@ -2139,8 +2139,8 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) gsm->tty =NULL ; } -static void gsmld_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int gsmld_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct gsm_mux *gsm = tty->disc_data;const unsigned char *dp;
@@ -2174,6 +2174,8 @@ static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, }/* FASYNC if needed ? */ /* If clogged call tty_throttle(tty); */ + +return count; }/**
drivers/tty/n_hdlc.c +10 -8
@@ -189,8 +189,8 @@ static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp, poll_table *wait);static int n_hdlc_tty_open (struct tty_struct *tty);static void n_hdlc_tty_close (struct tty_struct *tty); -static void n_hdlc_tty_receive (struct tty_struct *tty,const __u8 *cp, -char *fp,int count); +static unsigned int n_hdlc_tty_receive (struct tty_struct *tty, +const __u8 *cp,char *fp,int count);static void n_hdlc_tty_wakeup (struct tty_struct *tty);#define bset (p,b) ((p)[(b) >> 5] |= (1 << ((b) & 0x1f)))
@@ -510,8 +510,8 @@ static void n_hdlc_tty_wakeup(struct tty_struct *tty)* Called by tty low level driver when receive data is available. Data is * interpreted as one HDLC frame. */ -static void n_hdlc_tty_receive (struct tty_struct *tty,const __u8 *data, -char *flags,int count) +static unsigned int n_hdlc_tty_receive (struct tty_struct *tty, +const __u8 *data,char *flags,int count) { registerstruct n_hdlc *n_hdlc =tty2n_hdlc (tty); registerstruct n_hdlc_buf *buf;
@@ -522,20 +522,20 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,/* This can happen if stuff comes in on the backup tty */ if (!n_hdlc || tty != n_hdlc->tty) -return ; +return -ENODEV ;/* verify line is using HDLC discipline */ if (n_hdlc->magic !=HDLC_MAGIC ) {printk ("%s(%d) line not using HDLC discipline\n" , __FILE__,__LINE__); -return ; +return -EINVAL ; }if ( count>maxframe ) {if (debuglevel >=DEBUG_LEVEL_INFO )printk ("%s(%d) rx count>maxframesize, data discarded\n" , __FILE__,__LINE__); -return ; +return -EINVAL ; }/* get a free HDLC buffer */
@@ -551,7 +551,7 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,if (debuglevel >=DEBUG_LEVEL_INFO )printk ("%s(%d) no more rx buffers, data discarded\n" , __FILE__,__LINE__); -return ; +return -EINVAL ; }/* copy received data to HDLC buffer */
@@ -566,6 +566,8 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,if (n_hdlc->tty->fasync !=NULL )kill_fasync (&n_hdlc->tty->fasync,SIGIO ,POLL_IN ); +return count; + }/* end of n_hdlc_tty_receive() */ /**
drivers/tty/n_r3964.c +6 -4
@@ -140,8 +140,8 @@ static int r3964_ioctl(struct tty_struct *tty, struct file *file,static void r3964_set_termios (struct tty_struct *tty,struct ktermios *old);static unsigned int r3964_poll (struct tty_struct *tty,struct file *file,struct poll_table_struct *wait); -static void r3964_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count); +static unsigned int r3964_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count);static struct tty_ldisc_ops tty_ldisc_N_R3964 = { .owner =THIS_MODULE ,
@@ -1240,8 +1240,8 @@ static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,return result; } -static void r3964_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int r3964_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct r3964_info *pInfo = tty->disc_data;const unsigned char *p;
@@ -1258,6 +1258,8 @@ static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp, } } + +return count; }MODULE_LICENSE ("GPL" );
drivers/tty/n_tty.c +13 -41
136 lines not on this page · raw message
include/linux/tty_ldisc.h +5 -4
@@ -76,7 +76,7 @@* tty device. It is solely the responsibility of the line * discipline to handle poll requests. * -* void (*receive_buf)(struct tty_struct *, const unsigned char *cp, +* unsigned int (*receive_buf)(struct tty_struct *, const unsigned char *cp, * char *fp, int count); * * This function is called by the low-level tty driver to send
@@ -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. Returns the amount of bytes +* received. * * void (*write_wakeup)(struct tty_struct *); *
@@ -140,8 +141,8 @@ struct tty_ldisc_ops {/* * The following routines are called from below. */ -void (*receive_buf)(struct tty_struct *,const unsigned char *cp, -char *fp,int count); +unsigned int (*receive_buf)(struct tty_struct *, +const unsigned char *cp,char *fp,int count);void (*write_wakeup)(struct tty_struct *);void (*dcd_change)(struct tty_struct *,unsigned int ,struct pps_event_time *);
Signature · 1 line
1.7.4.1
Quoted 4 lines
Patch attached, please give it a good round of test as I don't have how to exercise all line disciplines. I ran 100 randconfigs over night and no warnings or erros on that area, at least not that I could see (so many warning while compiling the kernel :-( )
n_tty is I believe the only ldisc which assets throttling - the others actually prefer to lose data on an overflow not get further blockages.
Greg - can we get this into -next once -rc1 is out and see who screams ?
Quoted 10 lines · Alan Cox
Quoted 4 lines
Patch attached, please give it a good round of test as I don't have how to exercise all line disciplines. I ran 100 randconfigs over night and no warnings or erros on that area, at least not that I could see (so many warning while compiling the kernel :-( )
n_ttyis I believe the only ldisc which assets throttling - the others actually prefer to lose data on an overflow not get further blockages.Greg - can we get this into -next once -rc1 is out and see who screams ?
Yes, I will do that.
thanks,
greg k-h
Quoted 4 lines · Felipe Balbi
Patch attached, please give it a good round of test as I don't have how to exercise all line disciplines. I ran 100 randconfigs over night and no warnings or erros on that area, at least not that I could see (so many warning while compiling the kernel :-( )
Is this patch missing the changes to tty_buffer.c that were in http://permalink.gmane.org/gmane.linux.usb.general/28976
Without the changes to tty_buffer.c to use the value returned from the receive_buf call then doesn't this patch not work correctly?
Also with this patch, does the receive_room member of tty_struct have any use? As far as I can tell it's also referenced in paste_selection in drivers/tty/vt/selection.c. It's the case that past_selection uses receive_buf so shouldn't it be updated to use the new return value semantics for receive_buf?
Without modifying tty_buffer.c to not make use of receive_room I can't get console terminals to work with this patch. Although I have to admit that I've been applying the patch to 2.6.35.3 as that's the kernel my development board is currently using, but I can't see any immediate reason why the most recent kernel would be any different. However I'm still fairly new to the interactions between the various bits of tty code and drivers, so I could just be missing an important change that's in 2.6.38+.
Regards,
Toby
Hi,
Quoted 18 lines · Toby Gray
Quoted 4 lines · Felipe Balbi
Patch attached, please give it a good round of test as I don't have how to exercise all line disciplines. I ran 100 randconfigs over night and no warnings or erros on that area, at least not that I could see (so many warning while compiling the kernel :-( )
Is this patch missing the changes to
tty_buffer.cthat were in
http://permalink.gmane.org/gmane.linux.usb.general/28976Without the changes to
tty_buffer.cto use the value returned from thereceive_bufcall then doesn't this patch not work correctly?Also with this patch, does the
receive_roommember oftty_structhave any use? As far as I can tell it's also referenced inpaste_selectionindrivers/tty/vt/selection.c. It's the case thatpast_selectionusesreceive_bufso shouldn't it be updated to use the new return value semantics forreceive_buf?
Quoted 8 lines
Without modifying
tty_buffer.cto not make use ofreceive_roomI can't get console terminals to work with this patch. Although I have to admit that I've been applying the patch to 2.6.35.3 as that's the kernel my development board is currently using, but I can't see any immediate reason why the most recent kernel would be any different. However I'm still fairly new to the interactions between the various bits of tty code and drivers, so I could just be missing an important change that's in 2.6.38+.
you are right, thanks for noticing that. Attached is an updated patch. I left removal of receive_room out of this patch to prevent too invasive change, that can be done on a separate patch.
Signature · 1 line
balbi
Quoted 1 line
From
7f6e7b8bc6eed9ee1347d7555540801435a3cc43Mon Sep 17 00:00:00 2001
From: Felipe Balbi <[email protected]>
Date: Mon, 21 Mar 2011 12:25:08 +0200
Subject: [PATCH] tty: make receive_buf() return the amout of bytes received
Organization: Texas Instruments\n
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.
--- drivers/bluetooth/hci_ldisc.c | 12 +++++-- drivers/input/serio/serport.c | 10 +++++- drivers/isdn/gigaset/ser-gigaset.c | 8 +++-- drivers/misc/ti-st/st_core.c | 6 ++- drivers/net/caif/caif_serial.c | 6 ++- drivers/net/can/slcan.c | 9 ++++-- drivers/net/hamradio/6pack.c | 8 +++-- drivers/net/hamradio/mkiss.c | 11 ++++-- drivers/net/irda/irtty-sir.c | 16 ++++++---- drivers/net/ppp_async.c | 6 ++- drivers/net/ppp_synctty.c | 6 ++- drivers/net/slip.c | 11 ++++-- drivers/net/wan/x25_asy.c | 7 +++- drivers/tty/n_gsm.c | 6 ++- drivers/tty/n_hdlc.c | 18 ++++++----- drivers/tty/n_r3964.c | 10 ++++-- drivers/tty/n_tty.c | 54 ++++++++--------------------------- drivers/tty/tty_buffer.c | 7 ++-- drivers/tty/vt/selection.c | 3 +- include/linux/tty_ldisc.h | 9 +++-- 20 files changed, 118 insertions(+), 105 deletions(-)
drivers/bluetooth/hci_ldisc.c +8 -4
@@ -357,22 +357,26 @@ static void hci_uart_tty_wakeup(struct tty_struct *tty)* * Return Value: None */ -static void hci_uart_tty_receive (struct tty_struct *tty,const u8 *data,char *flags,int count) +static unsigned int hci_uart_tty_receive (struct tty_struct *tty, +const u8 *data,char *flags,int count) {struct hci_uart *hu = (void *)tty->disc_data; +int received;if (!hu || tty != hu->tty) -return ; +return -ENODEV ;if (!test_bit (HCI_UART_PROTO_SET , &hu->flags)) -return ; +return -EINVAL ;spin_lock (&hu->rx_lock); - hu->proto->recv (hu, (void *) data, count); + received = hu->proto->recv (hu, (void *) data, count); hu->hdev->stat.byte_rx += count;spin_unlock (&hu->rx_lock);tty_unthrottle (tty); + +return received; }static int hci_uart_register_dev (struct hci_uart *hu)
drivers/input/serio/serport.c +8 -2
@@ -120,17 +120,21 @@ static void serport_ldisc_close(struct tty_struct *tty)* 'interrupt' routine. */ -static void serport_ldisc_receive (struct tty_struct *tty,const unsigned char *cp,char *fp,int count) +static unsigned int serport_ldisc_receive (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct serport *serport = (struct serport *) tty->disc_data;unsigned long flags;unsigned int ch_flags; +int ret =0 ;int i;spin_lock_irqsave (&serport->lock, flags); -if (!test_bit (SERPORT_ACTIVE , &serport->flags)) +if (!test_bit (SERPORT_ACTIVE , &serport->flags)) { + ret = -EINVAL ; goto out; + }for (i =0 ; i < count; i++) {switch (fp[i]) {
@@ -152,6 +156,8 @@ static void serport_ldisc_receive(struct tty_struct *tty, const unsigned char *c out:spin_unlock_irqrestore (&serport->lock, flags); + +return ret ==0 ? count : ret; }/*
drivers/isdn/gigaset/ser-gigaset.c +5 -3
@@ -674,7 +674,7 @@ gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,* cflags buffer containing error flags for received characters (ignored) * count number of received characters */ -static void +static unsigned int gigaset_tty_receive (struct tty_struct *tty,const unsigned char *buf,char *cflags,int count) {
@@ -683,12 +683,12 @@ gigaset_tty_receive(struct tty_struct *tty, const unsigned char *buf,struct inbuf_t *inbuf;if (!cs) -return ; +return -ENODEV ; inbuf = cs->inbuf;if (!inbuf) {dev_err (cs->dev,"%s: no inbuf\n" , __func__);cs_put (cs); -return ; +return -EINVAL ; } tail = inbuf->tail;
@@ -725,6 +725,8 @@ gigaset_tty_receive(struct tty_struct *tty, const unsigned char *buf,gig_dbg (DEBUG_INTR ,"%s-->BH" , __func__);gigaset_schedule_event (cs);cs_put (cs); + +return count; }/*
drivers/misc/ti-st/st_core.c +4 -2
@@ -866,8 +866,8 @@ static void st_tty_close(struct tty_struct *tty)pr_debug ("%s: done " , __func__); } -static void st_tty_receive (struct tty_struct *tty,const unsigned char *data, -char *tty_flags,int count) +static unsigned int st_tty_receive (struct tty_struct *tty, +const unsigned char *data,char *tty_flags,int count) {#ifdef VERBOSE
@@ -881,6 +881,8 @@ static void st_tty_receive(struct tty_struct *tty, const unsigned char *data,*/ st_recv (tty->disc_data, data, count);pr_debug ("done %s" , __func__); + +return count; }/* wake-up function called in from the TTY layer
drivers/net/caif/caif_serial.c +4 -2
@@ -167,8 +167,8 @@ static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)#endif -static void ldisc_receive (struct tty_struct *tty,const u8 *data, -char *flags,int count) +static unsigned int ldisc_receive (struct tty_struct *tty, +const u8 *data,char *flags,int count) {struct sk_buff *skb =NULL ;struct ser_device *ser;
@@ -215,6 +215,8 @@ static void ldisc_receive(struct tty_struct *tty, const u8 *data, }else ++ser->dev->stats.rx_dropped;update_tty_status (ser); + +return count; }static int handle_tx (struct ser_device *ser)
drivers/net/can/slcan.c +6 -3
@@ -425,16 +425,17 @@ static void slc_setup(struct net_device *dev)* in parallel */ -static void slcan_receive_buf (struct tty_struct *tty, +static unsigned int slcan_receive_buf (struct tty_struct *tty,const unsigned char *cp,char *fp,int count) {struct slcan *sl = (struct slcan *) tty->disc_data; +int bytes = count;if (!sl || sl->magic !=SLCAN_MAGIC || !netif_running (sl->dev)) -return ; +return -ENODEV ;/* Read the characters out of the buffer */ -while (count--) { +while (bytes--) {if (fp && *fp++) {if (!test_and_set_bit (SLF_ERROR , &sl->flags)) sl->dev->stats.rx_errors++;
@@ -443,6 +444,8 @@ static void slcan_receive_buf(struct tty_struct *tty, }slcan_unesc (sl, *cp++); } + +return count; }/************************************
drivers/net/hamradio/6pack.c +5 -3
@@ -456,7 +456,7 @@ out:* a block of 6pack data has been received, which can now be decapsulated * and sent on to some IP layer for further processing. */ -static void sixpack_receive_buf (struct tty_struct *tty, +static unsigned int sixpack_receive_buf (struct tty_struct *tty,const unsigned char *cp,char *fp,int count) {struct sixpack *sp;
@@ -464,11 +464,11 @@ static void sixpack_receive_buf(struct tty_struct *tty,int count1;if (!count) -return ; +return 0 ; sp =sp_get (tty);if (!sp) -return ; +return -ENODEV ;memcpy (buf, cp, count <sizeof (buf) ? count :sizeof (buf));
@@ -487,6 +487,8 @@ static void sixpack_receive_buf(struct tty_struct *tty,sp_put (sp);tty_unthrottle (tty); + +return count1; }/*
drivers/net/hamradio/mkiss.c +7 -4
@@ -923,13 +923,14 @@ static long mkiss_compat_ioctl(struct tty_struct *tty, struct file *file,* a block of data has been received, which can now be decapsulated * and sent on to the AX.25 layer for further processing. */ -static void mkiss_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int mkiss_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct mkiss *ax =mkiss_get (tty); +int bytes = count;if (!ax) -return ; +return -ENODEV ;/* * Argh! mtu change time! - costs us the packet part received
@@ -939,7 +940,7 @@ static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,ax_changedmtu (ax);/* Read the characters out of the buffer */ -while (count--) { +while (bytes--) {if (fp !=NULL && *fp++) {if (!test_and_set_bit (AXF_ERROR , &ax->flags)) ax->dev->stats.rx_errors++;
@@ -952,6 +953,8 @@ static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,mkiss_put (ax);tty_unthrottle (tty); + +return count; }/*
drivers/net/irda/irtty-sir.c +9 -7
@@ -216,23 +216,23 @@ static int irtty_do_write(struct sir_dev *dev, const unsigned char *ptr, size_t* usbserial: urb-complete-interrupt / softint */ -static void irtty_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int irtty_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct sir_dev *dev;struct sirtty_cb *priv = tty->disc_data;int i; - IRDA_ASSERT(priv != NULL, return;); - IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;); + IRDA_ASSERT(priv != NULL, return -ENODEV;); + IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -EINVAL;);if (unlikely (count==0 ))/* yes, this happens */ -return ; +return 0 ; dev = priv->dev;if (!dev) {IRDA_WARNING ("%s(), not ready yet!\n" , __func__); -return ; +return -ENODEV ; }for (i =0 ; i < count; i++) {
@@ -242,11 +242,13 @@ static void irtty_receive_buf(struct tty_struct *tty, const unsigned char *cp,if (fp && *fp++) {IRDA_DEBUG (0 ,"Framing or parity error!\n" );sirdev_receive (dev,NULL ,0 );/* notify sir_dev (updating stats) */ -return ; +return -EINVAL ; } }sirdev_receive (dev, cp, count); + +return count; }/*
drivers/net/ppp_async.c +4 -2
@@ -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
drivers/net/ppp_synctty.c +4 -2
@@ -381,7 +381,7 @@ ppp_sync_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_sync_receive (struct tty_struct *tty,const unsigned char *buf,char *cflags,int count) {
@@ -389,7 +389,7 @@ ppp_sync_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_sync_input (ap, buf, cflags, count);spin_unlock_irqrestore (&ap->recv_lock, flags);
@@ -397,6 +397,8 @@ ppp_sync_receive(struct tty_struct *tty, const unsigned char *buf,tasklet_schedule (&ap->tsk);sp_put (ap);tty_unthrottle (tty); + +return count; } static void
drivers/net/slip.c +7 -4
@@ -670,16 +670,17 @@ static void sl_setup(struct net_device *dev)* in parallel */ -static void slip_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int slip_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct slip *sl = tty->disc_data; +int bytes = count;if (!sl || sl->magic !=SLIP_MAGIC || !netif_running (sl->dev)) -return ; +return -ENODEV ;/* Read the characters out of the buffer */ -while (count--) { +while (bytes--) {if (fp && *fp++) {if (!test_and_set_bit (SLF_ERROR , &sl->flags)) sl->dev->stats.rx_errors++;
@@ -693,6 +694,8 @@ static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp,#endif slip_unesc (sl, *cp++); } + +return count; }/************************************
drivers/net/wan/x25_asy.c +5 -2
@@ -517,17 +517,18 @@ static int x25_asy_close(struct net_device *dev)* and sent on to some IP layer for further processing. */ -static void x25_asy_receive_buf (struct tty_struct *tty, +static unsigned int x25_asy_receive_buf (struct tty_struct *tty,const unsigned char *cp,char *fp,int count) {struct x25_asy *sl = tty->disc_data; +int bytes = count;if (!sl || sl->magic !=X25_ASY_MAGIC || !netif_running (sl->dev))return ;/* Read the characters out of the buffer */ -while (count--) { +while (bytes--) {if (fp && *fp++) {if (!test_and_set_bit (SLF_ERROR , &sl->flags)) sl->dev->stats.rx_errors++;
@@ -536,6 +537,8 @@ static void x25_asy_receive_buf(struct tty_struct *tty, }x25_asy_unesc (sl, *cp++); } + +return count; }/*
drivers/tty/n_gsm.c +4 -2
@@ -2139,8 +2139,8 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) gsm->tty =NULL ; } -static void gsmld_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int gsmld_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct gsm_mux *gsm = tty->disc_data;const unsigned char *dp;
@@ -2174,6 +2174,8 @@ static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, }/* FASYNC if needed ? */ /* If clogged call tty_throttle(tty); */ + +return count; }/**
drivers/tty/n_hdlc.c +10 -8
@@ -189,8 +189,8 @@ static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp, poll_table *wait);static int n_hdlc_tty_open (struct tty_struct *tty);static void n_hdlc_tty_close (struct tty_struct *tty); -static void n_hdlc_tty_receive (struct tty_struct *tty,const __u8 *cp, -char *fp,int count); +static unsigned int n_hdlc_tty_receive (struct tty_struct *tty, +const __u8 *cp,char *fp,int count);static void n_hdlc_tty_wakeup (struct tty_struct *tty);#define bset (p,b) ((p)[(b) >> 5] |= (1 << ((b) & 0x1f)))
@@ -510,8 +510,8 @@ static void n_hdlc_tty_wakeup(struct tty_struct *tty)* Called by tty low level driver when receive data is available. Data is * interpreted as one HDLC frame. */ -static void n_hdlc_tty_receive (struct tty_struct *tty,const __u8 *data, -char *flags,int count) +static unsigned int n_hdlc_tty_receive (struct tty_struct *tty, +const __u8 *data,char *flags,int count) { registerstruct n_hdlc *n_hdlc =tty2n_hdlc (tty); registerstruct n_hdlc_buf *buf;
@@ -522,20 +522,20 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,/* This can happen if stuff comes in on the backup tty */ if (!n_hdlc || tty != n_hdlc->tty) -return ; +return -ENODEV ;/* verify line is using HDLC discipline */ if (n_hdlc->magic !=HDLC_MAGIC ) {printk ("%s(%d) line not using HDLC discipline\n" , __FILE__,__LINE__); -return ; +return -EINVAL ; }if ( count>maxframe ) {if (debuglevel >=DEBUG_LEVEL_INFO )printk ("%s(%d) rx count>maxframesize, data discarded\n" , __FILE__,__LINE__); -return ; +return -EINVAL ; }/* get a free HDLC buffer */
@@ -551,7 +551,7 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,if (debuglevel >=DEBUG_LEVEL_INFO )printk ("%s(%d) no more rx buffers, data discarded\n" , __FILE__,__LINE__); -return ; +return -EINVAL ; }/* copy received data to HDLC buffer */
@@ -566,6 +566,8 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,if (n_hdlc->tty->fasync !=NULL )kill_fasync (&n_hdlc->tty->fasync,SIGIO ,POLL_IN ); +return count; + }/* end of n_hdlc_tty_receive() */ /**
drivers/tty/n_r3964.c +6 -4
@@ -140,8 +140,8 @@ static int r3964_ioctl(struct tty_struct *tty, struct file *file,static void r3964_set_termios (struct tty_struct *tty,struct ktermios *old);static unsigned int r3964_poll (struct tty_struct *tty,struct file *file,struct poll_table_struct *wait); -static void r3964_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count); +static unsigned int r3964_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count);static struct tty_ldisc_ops tty_ldisc_N_R3964 = { .owner =THIS_MODULE ,
@@ -1240,8 +1240,8 @@ static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,return result; } -static void r3964_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int r3964_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct r3964_info *pInfo = tty->disc_data;const unsigned char *p;
@@ -1258,6 +1258,8 @@ static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp, } } + +return count; }MODULE_LICENSE ("GPL" );
drivers/tty/n_tty.c +13 -41
136 lines not on this page · raw message
drivers/tty/tty_buffer.c +3 -4
@@ -416,6 +416,7 @@ static void flush_to_ldisc(struct work_struct *work)struct tty_buffer *head, *tail = tty->buf.tail;int seen_tail =0 ;while ((head = tty->buf.head) !=NULL ) { +int copied;int count;char *char_buf;unsigned char *flag_buf;
@@ -446,15 +447,13 @@ static void flush_to_ldisc(struct work_struct *work)schedule_delayed_work (&tty->buf.work,1 );break ; } -if (count > tty->receive_room) - count = tty->receive_room; char_buf = head->char_buf_ptr + head->read; flag_buf = head->flag_buf_ptr + head->read; - head->read += count;spin_unlock_irqrestore (&tty->buf.lock, flags); - disc->ops->receive_buf (tty, char_buf, + copied = disc->ops->receive_buf (tty, char_buf, flag_buf, count);spin_lock_irqsave (&tty->buf.lock, flags); + head->read += copied; }clear_bit (TTY_FLUSHING , &tty->flags); }
drivers/tty/vt/selection.c +1 -2
@@ -335,8 +335,7 @@ int paste_selection(struct tty_struct *tty)continue ; } count = sel_buffer_lth - pasted; - count =min (count, tty->receive_room); - tty->ldisc->ops->receive_buf (tty, sel_buffer + pasted, + count = tty->ldisc->ops->receive_buf (tty, sel_buffer + pasted,NULL , count); pasted += count; }
include/linux/tty_ldisc.h +5 -4
@@ -76,7 +76,7 @@* tty device. It is solely the responsibility of the line * discipline to handle poll requests. * -* void (*receive_buf)(struct tty_struct *, const unsigned char *cp, +* unsigned int (*receive_buf)(struct tty_struct *, const unsigned char *cp, * char *fp, int count); * * This function is called by the low-level tty driver to send
@@ -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. Returns the amount of bytes +* received. * * void (*write_wakeup)(struct tty_struct *); *
@@ -140,8 +141,8 @@ struct tty_ldisc_ops {/* * The following routines are called from below. */ -void (*receive_buf)(struct tty_struct *,const unsigned char *cp, -char *fp,int count); +unsigned int (*receive_buf)(struct tty_struct *, +const unsigned char *cp,char *fp,int count);void (*write_wakeup)(struct tty_struct *);void (*dcd_change)(struct tty_struct *,unsigned int ,struct pps_event_time *);
Signature · 1 line
1.7.4.1.343.ga91df
Quoted 9 lines · Felipe Balbi
Hi,
Quoted 6 lines · Toby Gray
Is this patch missing the changes to
tty_buffer.cthat were in
http://permalink.gmane.org/gmane.linux.usb.general/28976Without the changes to
tty_buffer.cto use the value returned from thereceive_bufcall then doesn't this patch not work correctly?
<snip>
Quoted 3 lines
you are right, thanks for noticing that. Attached is an updated patch. I left removal of
receive_roomout of this patch to prevent too invasive change, that can be done on a separate patch.
I've just tried removing receive_room myself and noticed that it is still used in flush_to_ldisc to decide if it needs to schedule work to be done later:
if (!tty->receive_room || seen_tail) {
schedule_work(&tty->buf.work);
break;
}If receive_room is no longer being updated then isn't this the wrong thing to do? Shouldn't it check if some data was copied after calling receive_buf, and if there wasn't any then it should schedule the work and break?
The other query I've got is about the return value from receive_buf. I noticed that you've modified some drivers (such as bluetooth/hci_ldisc.c) so that they can return error values, such as -ENODEV. Won't this cause things to go wrong when flush_to_ldisc and paste_selection use the return value without checking for it being negative?
Thank you for your quick reply to my first query, it's appreciated.
Regards,
Toby
Quoted 29 lines · Toby Gray
Quoted 9 lines · Felipe Balbi
Hi,
Quoted 6 lines · Toby Gray
Is this patch missing the changes to
tty_buffer.cthat were in
http://permalink.gmane.org/gmane.linux.usb.general/28976Without the changes to
tty_buffer.cto use the value returned from thereceive_bufcall then doesn't this patch not work correctly?<snip>
Quoted 3 lines
you are right, thanks for noticing that. Attached is an updated patch. I left removal of
receive_roomout of this patch to prevent too invasive change, that can be done on a separate patch.I've just tried removing
receive_roommyself and noticed that it is still used inflush_to_ldiscto decide if it needs to schedule work to be done later:if (!tty->receive_room || seen_tail) { schedule_work(&tty->buf.work); break; }If
receive_roomis no longer being updated then isn't this the wrong thing to do? Shouldn't it check if some data was copied after callingreceive_buf, and if there wasn't any then it should schedule the work and break?
Quoted 8 lines
The other query I've got is about the return value from
receive_buf. I noticed that you've modified some drivers (such asbluetooth/hci_ldisc.c) so that they can return error values, such as-ENODEV. Won't this cause things to go wrong whenflush_to_ldiscandpaste_selectionuse the return value without checking for it being negative?Thank you for your quick reply to my first query, it's appreciated.
Can you try this:
drivers/tty/tty_buffer.c +6 -4
@@ -443,17 +443,19 @@ static void flush_to_ldisc(struct work_struct *work)line discipline as we want to empty the queue */ if (test_bit (TTY_FLUSHPENDING , &tty->flags))break ; -if (!tty->receive_room || seen_tail) { -schedule_delayed_work (&tty->buf.work,1 ); -break ; - } char_buf = head->char_buf_ptr + head->read; flag_buf = head->flag_buf_ptr + head->read;spin_unlock_irqrestore (&tty->buf.lock, flags); copied = disc->ops->receive_buf (tty, char_buf, flag_buf, count);spin_lock_irqsave (&tty->buf.lock, flags); + head->read += copied; + +if (copied ==0 || seen_tail) { +schedule_delayed_work (&tty->buf.work,1 ); +break ; + } }clear_bit (TTY_FLUSHING , &tty->flags); }
if I read the code correctly, when we have no space to receive bytes, then we schedule work, that should be the same.
Signature · 1 line
balbi
Can you try this:
drivers/tty/tty_buffer.c
Quoted 4 lines
drivers/tty/tty_buffer.c +0
-0
I tried it and the console is working again.
There is still an problem on heavy load transfer from host to gadget. I attached the patch to fix also this problem.
drivers/tty/n_tty.c +1 -0
@@ -1359,6 +1359,7 @@ static unsigned int n_tty_receive_buf(struct tty_struct *tty,memcpy (tty->read_buf + tty->read_head, cp, i); tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE -1 ); tty->read_cnt += i; + ret += i;spin_unlock_irqrestore (&tty->read_lock, cpuflags); }else { ret = count;
With this patch I was able to transfer gigabytes without lost data.
Quoted 25 lines · Stefan Bigler
Can you try this:
drivers/tty/tty_buffer.c
Quoted 4 lines
drivers/tty/tty_buffer.c +0
-0I tried it and the console is working again.
There is still an problem on heavy load transfer from host to gadget. I attached the patch to fix also this problem.drivers/tty/n_tty.c +1
-0@@ -1359,6 +1359,7 @@ static unsigned int n_tty_receive_buf(struct tty_struct *tty,memcpy (tty->read_buf + tty->read_head, cp, i); tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE -1 ); tty->read_cnt += i; + ret += i;spin_unlock_irqrestore (&tty->read_lock, cpuflags);} else { ret = count;
Quoted 1 line
With this patch I was able to transfer gigabytes without lost data.
I can confirm that this combined with the last two patches from Felipe Balbi fix all the issues I've had as well and seems stable and without loss under fast data transfers.
Regards,
Toby
Quoted 26 lines · Toby Gray
Quoted 25 lines · Stefan Bigler
Can you try this:
drivers/tty/tty_buffer.c
Quoted 4 lines
drivers/tty/tty_buffer.c +0
-0I tried it and the console is working again.
There is still an problem on heavy load transfer from host to gadget. I attached the patch to fix also this problem.drivers/tty/n_tty.c +1
-0@@ -1359,6 +1359,7 @@ static unsigned int n_tty_receive_buf(struct tty_struct *tty,memcpy (tty->read_buf + tty->read_head, cp, i); tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE -1 ); tty->read_cnt += i; + ret += i;spin_unlock_irqrestore (&tty->read_lock, cpuflags);} else { ret = count;
Quoted 5 lines
Quoted 1 line
With this patch I was able to transfer gigabytes without lost data.
I can confirm that this combined with the last two patches from Felipe Balbi fix all the issues I've had as well and seems stable and without loss under fast data transfers.
Great guys, thanks a lot. Here's the final patch with your Tested-bys
Signature · 1 line
balbi
Quoted 1 line
From
706cb57d502b6c04b865f3a822ae1369e1e55dfaMon Sep 17 00:00:00 2001
From: Felipe Balbi <[email protected]>
Date: Mon, 21 Mar 2011 12:25:08 +0200
Subject: [PATCH] tty: make receive_buf() return the amout of bytes received
Organization: Texas Instruments\n
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.
--- drivers/bluetooth/hci_ldisc.c | 12 +++++-- drivers/input/serio/serport.c | 10 +++++- drivers/isdn/gigaset/ser-gigaset.c | 8 +++-- drivers/misc/ti-st/st_core.c | 6 ++- drivers/net/caif/caif_serial.c | 6 ++- drivers/net/can/slcan.c | 9 ++++-- drivers/net/hamradio/6pack.c | 8 +++-- drivers/net/hamradio/mkiss.c | 11 ++++-- drivers/net/irda/irtty-sir.c | 16 ++++++---- drivers/net/ppp_async.c | 6 ++- drivers/net/ppp_synctty.c | 6 ++- drivers/net/slip.c | 11 ++++-- drivers/net/wan/x25_asy.c | 7 +++- drivers/tty/n_gsm.c | 6 ++- drivers/tty/n_hdlc.c | 18 ++++++----- drivers/tty/n_r3964.c | 10 ++++-- drivers/tty/n_tty.c | 55 +++++++++-------------------------- drivers/tty/tty_buffer.c | 17 ++++++----- drivers/tty/vt/selection.c | 3 +- include/linux/tty_ldisc.h | 9 +++-- 20 files changed, 125 insertions(+), 109 deletions(-)
drivers/bluetooth/hci_ldisc.c +8 -4
@@ -357,22 +357,26 @@ static void hci_uart_tty_wakeup(struct tty_struct *tty)* * Return Value: None */ -static void hci_uart_tty_receive (struct tty_struct *tty,const u8 *data,char *flags,int count) +static unsigned int hci_uart_tty_receive (struct tty_struct *tty, +const u8 *data,char *flags,int count) {struct hci_uart *hu = (void *)tty->disc_data; +int received;if (!hu || tty != hu->tty) -return ; +return -ENODEV ;if (!test_bit (HCI_UART_PROTO_SET , &hu->flags)) -return ; +return -EINVAL ;spin_lock (&hu->rx_lock); - hu->proto->recv (hu, (void *) data, count); + received = hu->proto->recv (hu, (void *) data, count); hu->hdev->stat.byte_rx += count;spin_unlock (&hu->rx_lock);tty_unthrottle (tty); + +return received; }static int hci_uart_register_dev (struct hci_uart *hu)
drivers/input/serio/serport.c +8 -2
@@ -120,17 +120,21 @@ static void serport_ldisc_close(struct tty_struct *tty)* 'interrupt' routine. */ -static void serport_ldisc_receive (struct tty_struct *tty,const unsigned char *cp,char *fp,int count) +static unsigned int serport_ldisc_receive (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct serport *serport = (struct serport *) tty->disc_data;unsigned long flags;unsigned int ch_flags; +int ret =0 ;int i;spin_lock_irqsave (&serport->lock, flags); -if (!test_bit (SERPORT_ACTIVE , &serport->flags)) +if (!test_bit (SERPORT_ACTIVE , &serport->flags)) { + ret = -EINVAL ; goto out; + }for (i =0 ; i < count; i++) {switch (fp[i]) {
@@ -152,6 +156,8 @@ static void serport_ldisc_receive(struct tty_struct *tty, const unsigned char *c out:spin_unlock_irqrestore (&serport->lock, flags); + +return ret ==0 ? count : ret; }/*
drivers/isdn/gigaset/ser-gigaset.c +5 -3
@@ -674,7 +674,7 @@ gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,* cflags buffer containing error flags for received characters (ignored) * count number of received characters */ -static void +static unsigned int gigaset_tty_receive (struct tty_struct *tty,const unsigned char *buf,char *cflags,int count) {
@@ -683,12 +683,12 @@ gigaset_tty_receive(struct tty_struct *tty, const unsigned char *buf,struct inbuf_t *inbuf;if (!cs) -return ; +return -ENODEV ; inbuf = cs->inbuf;if (!inbuf) {dev_err (cs->dev,"%s: no inbuf\n" , __func__);cs_put (cs); -return ; +return -EINVAL ; } tail = inbuf->tail;
@@ -725,6 +725,8 @@ gigaset_tty_receive(struct tty_struct *tty, const unsigned char *buf,gig_dbg (DEBUG_INTR ,"%s-->BH" , __func__);gigaset_schedule_event (cs);cs_put (cs); + +return count; }/*
drivers/misc/ti-st/st_core.c +4 -2
@@ -866,8 +866,8 @@ static void st_tty_close(struct tty_struct *tty)pr_debug ("%s: done " , __func__); } -static void st_tty_receive (struct tty_struct *tty,const unsigned char *data, -char *tty_flags,int count) +static unsigned int st_tty_receive (struct tty_struct *tty, +const unsigned char *data,char *tty_flags,int count) {#ifdef VERBOSE
@@ -881,6 +881,8 @@ static void st_tty_receive(struct tty_struct *tty, const unsigned char *data,*/ st_recv (tty->disc_data, data, count);pr_debug ("done %s" , __func__); + +return count; }/* wake-up function called in from the TTY layer
drivers/net/caif/caif_serial.c +4 -2
@@ -167,8 +167,8 @@ static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)#endif -static void ldisc_receive (struct tty_struct *tty,const u8 *data, -char *flags,int count) +static unsigned int ldisc_receive (struct tty_struct *tty, +const u8 *data,char *flags,int count) {struct sk_buff *skb =NULL ;struct ser_device *ser;
@@ -215,6 +215,8 @@ static void ldisc_receive(struct tty_struct *tty, const u8 *data, }else ++ser->dev->stats.rx_dropped;update_tty_status (ser); + +return count; }static int handle_tx (struct ser_device *ser)
drivers/net/can/slcan.c +6 -3
@@ -425,16 +425,17 @@ static void slc_setup(struct net_device *dev)* in parallel */ -static void slcan_receive_buf (struct tty_struct *tty, +static unsigned int slcan_receive_buf (struct tty_struct *tty,const unsigned char *cp,char *fp,int count) {struct slcan *sl = (struct slcan *) tty->disc_data; +int bytes = count;if (!sl || sl->magic !=SLCAN_MAGIC || !netif_running (sl->dev)) -return ; +return -ENODEV ;/* Read the characters out of the buffer */ -while (count--) { +while (bytes--) {if (fp && *fp++) {if (!test_and_set_bit (SLF_ERROR , &sl->flags)) sl->dev->stats.rx_errors++;
@@ -443,6 +444,8 @@ static void slcan_receive_buf(struct tty_struct *tty, }slcan_unesc (sl, *cp++); } + +return count; }/************************************
drivers/net/hamradio/6pack.c +5 -3
@@ -456,7 +456,7 @@ out:* a block of 6pack data has been received, which can now be decapsulated * and sent on to some IP layer for further processing. */ -static void sixpack_receive_buf (struct tty_struct *tty, +static unsigned int sixpack_receive_buf (struct tty_struct *tty,const unsigned char *cp,char *fp,int count) {struct sixpack *sp;
@@ -464,11 +464,11 @@ static void sixpack_receive_buf(struct tty_struct *tty,int count1;if (!count) -return ; +return 0 ; sp =sp_get (tty);if (!sp) -return ; +return -ENODEV ;memcpy (buf, cp, count <sizeof (buf) ? count :sizeof (buf));
@@ -487,6 +487,8 @@ static void sixpack_receive_buf(struct tty_struct *tty,sp_put (sp);tty_unthrottle (tty); + +return count1; }/*
drivers/net/hamradio/mkiss.c +7 -4
@@ -923,13 +923,14 @@ static long mkiss_compat_ioctl(struct tty_struct *tty, struct file *file,* a block of data has been received, which can now be decapsulated * and sent on to the AX.25 layer for further processing. */ -static void mkiss_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int mkiss_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct mkiss *ax =mkiss_get (tty); +int bytes = count;if (!ax) -return ; +return -ENODEV ;/* * Argh! mtu change time! - costs us the packet part received
@@ -939,7 +940,7 @@ static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,ax_changedmtu (ax);/* Read the characters out of the buffer */ -while (count--) { +while (bytes--) {if (fp !=NULL && *fp++) {if (!test_and_set_bit (AXF_ERROR , &ax->flags)) ax->dev->stats.rx_errors++;
@@ -952,6 +953,8 @@ static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,mkiss_put (ax);tty_unthrottle (tty); + +return count; }/*
drivers/net/irda/irtty-sir.c +9 -7
@@ -216,23 +216,23 @@ static int irtty_do_write(struct sir_dev *dev, const unsigned char *ptr, size_t* usbserial: urb-complete-interrupt / softint */ -static void irtty_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int irtty_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct sir_dev *dev;struct sirtty_cb *priv = tty->disc_data;int i; - IRDA_ASSERT(priv != NULL, return;); - IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;); + IRDA_ASSERT(priv != NULL, return -ENODEV;); + IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -EINVAL;);if (unlikely (count==0 ))/* yes, this happens */ -return ; +return 0 ; dev = priv->dev;if (!dev) {IRDA_WARNING ("%s(), not ready yet!\n" , __func__); -return ; +return -ENODEV ; }for (i =0 ; i < count; i++) {
@@ -242,11 +242,13 @@ static void irtty_receive_buf(struct tty_struct *tty, const unsigned char *cp,if (fp && *fp++) {IRDA_DEBUG (0 ,"Framing or parity error!\n" );sirdev_receive (dev,NULL ,0 );/* notify sir_dev (updating stats) */ -return ; +return -EINVAL ; } }sirdev_receive (dev, cp, count); + +return count; }/*
drivers/net/ppp_async.c +4 -2
@@ -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
drivers/net/ppp_synctty.c +4 -2
@@ -381,7 +381,7 @@ ppp_sync_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_sync_receive (struct tty_struct *tty,const unsigned char *buf,char *cflags,int count) {
@@ -389,7 +389,7 @@ ppp_sync_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_sync_input (ap, buf, cflags, count);spin_unlock_irqrestore (&ap->recv_lock, flags);
@@ -397,6 +397,8 @@ ppp_sync_receive(struct tty_struct *tty, const unsigned char *buf,tasklet_schedule (&ap->tsk);sp_put (ap);tty_unthrottle (tty); + +return count; } static void
drivers/net/slip.c +7 -4
@@ -670,16 +670,17 @@ static void sl_setup(struct net_device *dev)* in parallel */ -static void slip_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int slip_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct slip *sl = tty->disc_data; +int bytes = count;if (!sl || sl->magic !=SLIP_MAGIC || !netif_running (sl->dev)) -return ; +return -ENODEV ;/* Read the characters out of the buffer */ -while (count--) { +while (bytes--) {if (fp && *fp++) {if (!test_and_set_bit (SLF_ERROR , &sl->flags)) sl->dev->stats.rx_errors++;
@@ -693,6 +694,8 @@ static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp,#endif slip_unesc (sl, *cp++); } + +return count; }/************************************
drivers/net/wan/x25_asy.c +5 -2
@@ -517,17 +517,18 @@ static int x25_asy_close(struct net_device *dev)* and sent on to some IP layer for further processing. */ -static void x25_asy_receive_buf (struct tty_struct *tty, +static unsigned int x25_asy_receive_buf (struct tty_struct *tty,const unsigned char *cp,char *fp,int count) {struct x25_asy *sl = tty->disc_data; +int bytes = count;if (!sl || sl->magic !=X25_ASY_MAGIC || !netif_running (sl->dev))return ;/* Read the characters out of the buffer */ -while (count--) { +while (bytes--) {if (fp && *fp++) {if (!test_and_set_bit (SLF_ERROR , &sl->flags)) sl->dev->stats.rx_errors++;
@@ -536,6 +537,8 @@ static void x25_asy_receive_buf(struct tty_struct *tty, }x25_asy_unesc (sl, *cp++); } + +return count; }/*
drivers/tty/n_gsm.c +4 -2
@@ -2139,8 +2139,8 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) gsm->tty =NULL ; } -static void gsmld_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int gsmld_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct gsm_mux *gsm = tty->disc_data;const unsigned char *dp;
@@ -2174,6 +2174,8 @@ static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, }/* FASYNC if needed ? */ /* If clogged call tty_throttle(tty); */ + +return count; }/**
drivers/tty/n_hdlc.c +10 -8
@@ -189,8 +189,8 @@ static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp, poll_table *wait);static int n_hdlc_tty_open (struct tty_struct *tty);static void n_hdlc_tty_close (struct tty_struct *tty); -static void n_hdlc_tty_receive (struct tty_struct *tty,const __u8 *cp, -char *fp,int count); +static unsigned int n_hdlc_tty_receive (struct tty_struct *tty, +const __u8 *cp,char *fp,int count);static void n_hdlc_tty_wakeup (struct tty_struct *tty);#define bset (p,b) ((p)[(b) >> 5] |= (1 << ((b) & 0x1f)))
@@ -510,8 +510,8 @@ static void n_hdlc_tty_wakeup(struct tty_struct *tty)* Called by tty low level driver when receive data is available. Data is * interpreted as one HDLC frame. */ -static void n_hdlc_tty_receive (struct tty_struct *tty,const __u8 *data, -char *flags,int count) +static unsigned int n_hdlc_tty_receive (struct tty_struct *tty, +const __u8 *data,char *flags,int count) { registerstruct n_hdlc *n_hdlc =tty2n_hdlc (tty); registerstruct n_hdlc_buf *buf;
@@ -522,20 +522,20 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,/* This can happen if stuff comes in on the backup tty */ if (!n_hdlc || tty != n_hdlc->tty) -return ; +return -ENODEV ;/* verify line is using HDLC discipline */ if (n_hdlc->magic !=HDLC_MAGIC ) {printk ("%s(%d) line not using HDLC discipline\n" , __FILE__,__LINE__); -return ; +return -EINVAL ; }if ( count>maxframe ) {if (debuglevel >=DEBUG_LEVEL_INFO )printk ("%s(%d) rx count>maxframesize, data discarded\n" , __FILE__,__LINE__); -return ; +return -EINVAL ; }/* get a free HDLC buffer */
@@ -551,7 +551,7 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,if (debuglevel >=DEBUG_LEVEL_INFO )printk ("%s(%d) no more rx buffers, data discarded\n" , __FILE__,__LINE__); -return ; +return -EINVAL ; }/* copy received data to HDLC buffer */
@@ -566,6 +566,8 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,if (n_hdlc->tty->fasync !=NULL )kill_fasync (&n_hdlc->tty->fasync,SIGIO ,POLL_IN ); +return count; + }/* end of n_hdlc_tty_receive() */ /**
drivers/tty/n_r3964.c +6 -4
@@ -140,8 +140,8 @@ static int r3964_ioctl(struct tty_struct *tty, struct file *file,static void r3964_set_termios (struct tty_struct *tty,struct ktermios *old);static unsigned int r3964_poll (struct tty_struct *tty,struct file *file,struct poll_table_struct *wait); -static void r3964_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count); +static unsigned int r3964_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count);static struct tty_ldisc_ops tty_ldisc_N_R3964 = { .owner =THIS_MODULE ,
@@ -1240,8 +1240,8 @@ static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,return result; } -static void r3964_receive_buf (struct tty_struct *tty,const unsigned char *cp, -char *fp,int count) +static unsigned int r3964_receive_buf (struct tty_struct *tty, +const unsigned char *cp,char *fp,int count) {struct r3964_info *pInfo = tty->disc_data;const unsigned char *p;
@@ -1258,6 +1258,8 @@ static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp, } } + +return count; }MODULE_LICENSE ("GPL" );
drivers/tty/n_tty.c +14 -41
139 lines not on this page · raw message
drivers/tty/tty_buffer.c +9 -8
@@ -416,6 +416,7 @@ static void flush_to_ldisc(struct work_struct *work)struct tty_buffer *head, *tail = tty->buf.tail;int seen_tail =0 ;while ((head = tty->buf.head) !=NULL ) { +int copied;int count;char *char_buf;unsigned char *flag_buf;
@@ -442,19 +443,19 @@ static void flush_to_ldisc(struct work_struct *work)line discipline as we want to empty the queue */ if (test_bit (TTY_FLUSHPENDING , &tty->flags))break ; -if (!tty->receive_room || seen_tail) { -schedule_delayed_work (&tty->buf.work,1 ); -break ; - } -if (count > tty->receive_room) - count = tty->receive_room; char_buf = head->char_buf_ptr + head->read; flag_buf = head->flag_buf_ptr + head->read; - head->read += count;spin_unlock_irqrestore (&tty->buf.lock, flags); - disc->ops->receive_buf (tty, char_buf, + copied = disc->ops->receive_buf (tty, char_buf, flag_buf, count);spin_lock_irqsave (&tty->buf.lock, flags); + + head->read += copied; + +if (copied ==0 || seen_tail) { +schedule_delayed_work (&tty->buf.work,1 ); +break ; + } }clear_bit (TTY_FLUSHING , &tty->flags); }
drivers/tty/vt/selection.c +1 -2
@@ -335,8 +335,7 @@ int paste_selection(struct tty_struct *tty)continue ; } count = sel_buffer_lth - pasted; - count =min (count, tty->receive_room); - tty->ldisc->ops->receive_buf (tty, sel_buffer + pasted, + count = tty->ldisc->ops->receive_buf (tty, sel_buffer + pasted,NULL , count); pasted += count; }
include/linux/tty_ldisc.h +5 -4
@@ -76,7 +76,7 @@* tty device. It is solely the responsibility of the line * discipline to handle poll requests. * -* void (*receive_buf)(struct tty_struct *, const unsigned char *cp, +* unsigned int (*receive_buf)(struct tty_struct *, const unsigned char *cp, * char *fp, int count); * * This function is called by the low-level tty driver to send
@@ -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. Returns the amount of bytes +* received. * * void (*write_wakeup)(struct tty_struct *); *
@@ -140,8 +141,8 @@ struct tty_ldisc_ops {/* * The following routines are called from below. */ -void (*receive_buf)(struct tty_struct *,const unsigned char *cp, -char *fp,int count); +unsigned int (*receive_buf)(struct tty_struct *, +const unsigned char *cp,char *fp,int count);void (*write_wakeup)(struct tty_struct *);void (*dcd_change)(struct tty_struct *,unsigned int ,struct pps_event_time *);
Signature · 1 line
1.7.4.1.343.ga91df
Hi
Returning the size of queued data is a reasonable solution for this problem.
Stefan
Quoted 2 lines
I had also a look at the relevant fixes, a lot is done but I could not find the required protection of the attribute
receive_room.
receive_room isn't protected because it may only be shrunk by the amount of data sent to the ldisc or less. The ldisc is at liberty to grow the value as it sees fit.
In essence if you get a value from receive_room it's a guarantee you may send that many bytes, it is not a precise instantaneous perfect answer to the question "exactly what number of bytes could fit at this precise moment".
Which does of course mean you should never see the case where receive_room is bigger than the actual space available in tty raw mode.
Quoted 6 lines
In essence if you get a value from
receive_roomit's a guarantee you may send that many bytes, it is not a precise instantaneous perfect answer to the question "exactly what number of bytes could fit at this precise moment".
Hi
I have no problem with having more space available than guarantied by the value of receive_room. But what I see is that the value can be less! Data will be lost.
My test showed:
data to queue=201
receive_room (guarantied space) =287
real space in queue =0
In the last mail I attached the code for printing, the read_lock was only added to show a constistant view of all current values.
Stefan