From 26df6d13406d1a53b0bda08bd712f1924affd7cd Mon Sep 17 00:00:00 2001 From: "hyc@symas.com" Date: Tue, 22 Jun 2010 10:14:49 -0700 Subject: tty: Add EXTPROC support for LINEMODE This patch is against the 2.6.34 source. Paraphrased from the 1989 BSD patch by David Borman @ cray.com: These are the changes needed for the kernel to support LINEMODE in the server. There is a new bit in the termios local flag word, EXTPROC. When this bit is set, several aspects of the terminal driver are disabled. Input line editing, character echo, and mapping of signals are all disabled. This allows the telnetd to turn off these functions when in linemode, but still keep track of what state the user wants the terminal to be in. New ioctl: TIOCSIG Generate a signal to processes in the current process group of the pty. There is a new mode for packet driver, the TIOCPKT_IOCTL bit. When packet mode is turned on in the pty, and the EXTPROC bit is set, then whenever the state of the pty is changed, the next read on the master side of the pty will have the TIOCPKT_IOCTL bit set. This allows the process on the server side of the pty to know when the state of the terminal has changed; it can then issue the appropriate ioctl to retrieve the new state. Since the original BSD patches accompanied the source code for telnet I've left that reference here, but obviously the feature is useful for any remote terminal protocol, including ssh. The corresponding feature has existed in the BSD tty driver since 1989. For historical reference, a good copy of the relevant files can be found here: http://anonsvn.mit.edu/viewvc/krb5/trunk/src/appl/telnet/?pathrev=17741 Signed-off-by: Howard Chu Cc: Alan Cox Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 7802a243ee13..2df60e4ff40e 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -179,6 +179,7 @@ struct tty_bufhead { #define L_FLUSHO(tty) _L_FLAG((tty), FLUSHO) #define L_PENDIN(tty) _L_FLAG((tty), PENDIN) #define L_IEXTEN(tty) _L_FLAG((tty), IEXTEN) +#define L_EXTPROC(tty) _L_FLAG((tty), EXTPROC) struct device; struct signal_struct; -- cgit v1.2.3 From ec79d6056de58511d8e46d9ae59d3878f958dc3e Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 1 Jun 2010 22:53:01 +0200 Subject: tty: replace BKL with a new tty_lock As a preparation for replacing the big kernel lock in the TTY layer, wrap all the callers in new macros tty_lock, tty_lock_nested and tty_unlock. Signed-off-by: Arnd Bergmann Cc: Alan Cox Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 2df60e4ff40e..6ead6b60c743 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -13,6 +13,7 @@ #include #include #include +#include #include @@ -576,5 +577,35 @@ extern int vt_ioctl(struct tty_struct *tty, struct file *file, extern long vt_compat_ioctl(struct tty_struct *tty, struct file * file, unsigned int cmd, unsigned long arg); +/* functions for preparation of BKL removal */ + +/* + * tty_lock_nested get the tty_lock while potentially holding it + * + * The Big TTY Mutex is a recursive lock, meaning you can take it + * from a thread that is already holding it. + * This is bad for a number of reasons, so tty_lock_nested should + * really be used as rarely as possible. If a code location can + * be shown to never get called with this held already, it should + * use tty_lock() instead. + */ +static inline void __lockfunc tty_lock_nested(void) __acquires(kernel_lock) +{ + lock_kernel(); +} +static inline void tty_lock(void) __acquires(kernel_lock) +{ +#ifdef CONFIG_LOCK_KERNEL + /* kernel_locked is 1 for !CONFIG_LOCK_KERNEL */ + WARN_ON(kernel_locked()); +#endif + lock_kernel(); +} +static inline void tty_unlock(void) __releases(kernel_lock) +{ + unlock_kernel(); +} +#define tty_locked() (kernel_locked()) + #endif /* __KERNEL__ */ #endif -- cgit v1.2.3 From be1bc2889a4db4961ef69f47fb471ecae9f23ade Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 1 Jun 2010 22:53:05 +0200 Subject: tty: introduce wait_event_interruptible_tty Calling wait_event_interruptible implicitly releases the BKL when it sleeps, but we need to do this explcitly when we have converted it to a mutex. Signed-off-by: Arnd Bergmann Cc: Alan Cox Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 6ead6b60c743..955d72ea71c0 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -607,5 +607,47 @@ static inline void tty_unlock(void) __releases(kernel_lock) } #define tty_locked() (kernel_locked()) +/* + * wait_event_interruptible_tty -- wait for a condition with the tty lock held + * + * The condition we are waiting for might take a long time to + * become true, or might depend on another thread taking the + * BTM. In either case, we need to drop the BTM to guarantee + * forward progress. This is a leftover from the conversion + * from the BKL and should eventually get removed as the BTM + * falls out of use. + * + * Do not use in new code. + */ +#define wait_event_interruptible_tty(wq, condition) \ +({ \ + int __ret = 0; \ + if (!(condition)) { \ + __wait_event_interruptible_tty(wq, condition, __ret); \ + } \ + __ret; \ +}) + +#define __wait_event_interruptible_tty(wq, condition, ret) \ +do { \ + DEFINE_WAIT(__wait); \ + \ + for (;;) { \ + prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \ + if (condition) \ + break; \ + if (!signal_pending(current)) { \ + tty_unlock(); \ + schedule(); \ + tty_lock(); \ + continue; \ + } \ + ret = -ERESTARTSYS; \ + break; \ + } \ + finish_wait(&wq, &__wait); \ +} while (0) + + #endif /* __KERNEL__ */ #endif -- cgit v1.2.3 From ddcd9fb66ae7f448b517242c10a31d4e17bcad45 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 1 Jun 2010 22:53:08 +0200 Subject: tty: remove tty_lock_nested This changes all remaining users of tty_lock_nested to be non-recursive, which lets us kill this function. As a consequence, we won't need to keep the lock count any more, which allows more simplifications later. Signed-off-by: Arnd Bergmann Cc: Alan Cox Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 16 +--------------- 1 file changed, 1 insertion(+), 15 deletions(-) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 955d72ea71c0..0fbafb0b69bf 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -417,6 +417,7 @@ extern int is_ignored(int sig); extern int tty_signal(int sig, struct tty_struct *tty); extern void tty_hangup(struct tty_struct *tty); extern void tty_vhangup(struct tty_struct *tty); +extern void tty_vhangup_locked(struct tty_struct *tty); extern void tty_vhangup_self(void); extern void tty_unhangup(struct file *filp); extern int tty_hung_up_p(struct file *filp); @@ -578,21 +579,6 @@ extern long vt_compat_ioctl(struct tty_struct *tty, struct file * file, unsigned int cmd, unsigned long arg); /* functions for preparation of BKL removal */ - -/* - * tty_lock_nested get the tty_lock while potentially holding it - * - * The Big TTY Mutex is a recursive lock, meaning you can take it - * from a thread that is already holding it. - * This is bad for a number of reasons, so tty_lock_nested should - * really be used as rarely as possible. If a code location can - * be shown to never get called with this held already, it should - * use tty_lock() instead. - */ -static inline void __lockfunc tty_lock_nested(void) __acquires(kernel_lock) -{ - lock_kernel(); -} static inline void tty_lock(void) __acquires(kernel_lock) { #ifdef CONFIG_LOCK_KERNEL -- cgit v1.2.3 From b07471fa51358ce64cc25e1501544502362e4404 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 6 Aug 2010 21:40:30 +0200 Subject: tty: implement BTM as mutex instead of BKL The tty locking now follows the rules for mutexes, so we can replace the BKL usage with a new subsystem wide mutex. Using a regular mutex here will change the behaviour when blocked on the BTM from spinning to sleeping, but that should not be visible to the user. Using the mutex also means that all the BTM is now covered by lockdep. Signed-off-by: Arnd Bergmann Cc: Alan Cox Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 18 +++++------------- 1 file changed, 5 insertions(+), 13 deletions(-) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 0fbafb0b69bf..1437da3ddc62 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -578,20 +578,12 @@ extern int vt_ioctl(struct tty_struct *tty, struct file *file, extern long vt_compat_ioctl(struct tty_struct *tty, struct file * file, unsigned int cmd, unsigned long arg); +/* tty_mutex.c */ /* functions for preparation of BKL removal */ -static inline void tty_lock(void) __acquires(kernel_lock) -{ -#ifdef CONFIG_LOCK_KERNEL - /* kernel_locked is 1 for !CONFIG_LOCK_KERNEL */ - WARN_ON(kernel_locked()); -#endif - lock_kernel(); -} -static inline void tty_unlock(void) __releases(kernel_lock) -{ - unlock_kernel(); -} -#define tty_locked() (kernel_locked()) +extern void __lockfunc tty_lock(void) __acquires(tty_lock); +extern void __lockfunc tty_unlock(void) __releases(tty_lock); +extern struct task_struct *__big_tty_mutex_owner; +#define tty_locked() (current == __big_tty_mutex_owner) /* * wait_event_interruptible_tty -- wait for a condition with the tty lock held -- cgit v1.2.3 From ee2ffa0dfdd2db19705f2ba1c6a4c0bfe8122dd8 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 18 Aug 2010 04:37:35 +1000 Subject: fs: cleanup files_lock locking fs: cleanup files_lock locking Lock tty_files with a new spinlock, tty_files_lock; provide helpers to manipulate the per-sb files list; unexport the files_lock spinlock. Cc: linux-kernel@vger.kernel.org Cc: Christoph Hellwig Cc: Alan Cox Acked-by: Andi Kleen Acked-by: Greg Kroah-Hartman Signed-off-by: Nick Piggin Signed-off-by: Al Viro --- include/linux/tty.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 1437da3ddc62..f6b371a2514e 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -470,6 +470,7 @@ extern struct tty_struct *tty_pair_get_tty(struct tty_struct *tty); extern struct tty_struct *tty_pair_get_pty(struct tty_struct *tty); extern struct mutex tty_mutex; +extern spinlock_t tty_files_lock; extern void tty_write_unlock(struct tty_struct *tty); extern int tty_write_lock(struct tty_struct *tty, int ndelay); -- cgit v1.2.3 From d996b62a8df1d935b01319bf8defb95b5709f7b8 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 18 Aug 2010 04:37:36 +1000 Subject: tty: fix fu_list abuse tty: fix fu_list abuse tty code abuses fu_list, which causes a bug in remount,ro handling. If a tty device node is opened on a filesystem, then the last link to the inode removed, the filesystem will be allowed to be remounted readonly. This is because fs_may_remount_ro does not find the 0 link tty inode on the file sb list (because the tty code incorrectly removed it to use for its own purpose). This can result in a filesystem with errors after it is marked "clean". Taking idea from Christoph's initial patch, allocate a tty private struct at file->private_data and put our required list fields in there, linking file and tty. This makes tty nodes behave the same way as other device nodes and avoid meddling with the vfs, and avoids this bug. The error handling is not trivial in the tty code, so for this bugfix, I take the simple approach of using __GFP_NOFAIL and don't worry about memory errors. This is not a problem because our allocator doesn't fail small allocs as a rule anyway. So proper error handling is left as an exercise for tty hackers. [ Arguably filesystem's device inode would ideally be divorced from the driver's pseudo inode when it is opened, but in practice it's not clear whether that will ever be worth implementing. ] Cc: linux-kernel@vger.kernel.org Cc: Christoph Hellwig Cc: Alan Cox Cc: Greg Kroah-Hartman Signed-off-by: Nick Piggin Signed-off-by: Al Viro --- include/linux/tty.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index f6b371a2514e..67d64e6efe7a 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -329,6 +329,13 @@ struct tty_struct { struct tty_port *port; }; +/* Each of a tty's open files has private_data pointing to tty_file_private */ +struct tty_file_private { + struct tty_struct *tty; + struct file *file; + struct list_head list; +}; + /* tty magic number */ #define TTY_MAGIC 0x5401 @@ -458,6 +465,7 @@ extern void proc_clear_tty(struct task_struct *p); extern struct tty_struct *get_current_tty(void); extern void tty_default_fops(struct file_operations *fops); extern struct tty_struct *alloc_tty_struct(void); +extern void tty_add_file(struct tty_struct *tty, struct file *file); extern void free_tty_struct(struct tty_struct *tty); extern void initialize_tty_struct(struct tty_struct *tty, struct tty_driver *driver, int idx); -- cgit v1.2.3 From 40fb29a777d23b1161271ec88fd21739835e4f6a Mon Sep 17 00:00:00 2001 From: Pavan Savoy Date: Thu, 30 Sep 2010 16:13:28 -0400 Subject: tty.h: new ldisc for TI WiLink ST Texas Instrument's WiLink7 connectivity devices pack wireless connectivity technologies like Bluetooth, FM Radio Receiver and Transmitter, GPS and WLAN into a single die. The BT, FM and GPS core on the chip are interfaced to application processors via a single UART. This line discipline driver allows such different technologies to be used simultaneous and independent of each other. Signed-off-by: Pavan Savoy Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 67d64e6efe7a..244bb8de2b92 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -50,6 +50,7 @@ #define N_V253 19 /* Codec control over voice modem */ #define N_CAIF 20 /* CAIF protocol for talking to modems */ #define N_GSM0710 21 /* GSM 0710 Mux */ +#define N_TI_WL 22 /* for TI's WL BT, FM, GPS combo chips */ /* * This character is the same as _POSIX_VDISABLE: it cannot be used as -- cgit v1.2.3 From 30004ac9c090dcdcca99556b4587b3bad828731a Mon Sep 17 00:00:00 2001 From: Dmitry Eremin-Solenikov Date: Mon, 9 Aug 2010 18:22:49 +0400 Subject: tty: add tty_struct->dev pointer to corresponding device instance Some device drivers (mostly tty line disciplines) would like to have way know a struct device instance corresponding to passed tty_struct. Add a struct device pointer to struct tty_struct and populate it during initialize_tty_struct(). Signed-off-by: Dmitry Eremin-Solenikov Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 67d64e6efe7a..d94eb86266c4 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -256,6 +256,7 @@ struct tty_operations; struct tty_struct { int magic; struct kref kref; + struct device *dev; struct tty_driver *driver; const struct tty_operations *ops; int index; -- cgit v1.2.3 From f573bd1764f0f3f47754ca1ae7b2eb2909798a60 Mon Sep 17 00:00:00 2001 From: Pekka Enberg Date: Tue, 24 Aug 2010 07:48:34 +0300 Subject: tty: Remove __GFP_NOFAIL from tty_add_file() This patch removes __GFP_NOFAIL use from tty_add_file() and adds proper error handling to the call-sites of the function. Cc: Andrew Morton Cc: Alan Cox Cc: Arnd Bergmann Signed-off-by: Pekka Enberg Acked-by: David Rientjes Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index d94eb86266c4..86be0cdeb11b 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -466,7 +466,7 @@ extern void proc_clear_tty(struct task_struct *p); extern struct tty_struct *get_current_tty(void); extern void tty_default_fops(struct file_operations *fops); extern struct tty_struct *alloc_tty_struct(void); -extern void tty_add_file(struct tty_struct *tty, struct file *file); +extern int tty_add_file(struct tty_struct *tty, struct file *file); extern void free_tty_struct(struct tty_struct *tty); extern void initialize_tty_struct(struct tty_struct *tty, struct tty_driver *driver, int idx); -- cgit v1.2.3 From 3c80fe4ac9cfb13b1bfa4edf1544e8b656716694 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 9 Dec 2009 14:19:31 +0000 Subject: audit: Call tty_audit_push_task() outside preempt disabled While auditing all tasklist_lock read_lock sites I stumbled over the following call chain: audit_prepare_user_tty() read_lock(&tasklist_lock); tty_audit_push_task(); mutex_lock(&buf->mutex); --> buf->mutex is locked with preemption disabled. Solve this by acquiring a reference to the task struct under rcu_read_lock and call tty_audit_push_task outside of the preempt disabled region. Move all code which needs to be protected by sighand lock into tty_audit_push_task() and use lock/unlock_sighand as we do not hold tasklist_lock. Signed-off-by: Thomas Gleixner Cc: Al Viro Cc: Eric Paris Cc: Oleg Nesterov Signed-off-by: Al Viro --- include/linux/tty.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index e500171c745f..2a754748dd5f 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -541,8 +541,8 @@ extern void tty_audit_exit(void); extern void tty_audit_fork(struct signal_struct *sig); extern void tty_audit_tiocsti(struct tty_struct *tty, char ch); extern void tty_audit_push(struct tty_struct *tty); -extern void tty_audit_push_task(struct task_struct *tsk, - uid_t loginuid, u32 sessionid); +extern int tty_audit_push_task(struct task_struct *tsk, + uid_t loginuid, u32 sessionid); #else static inline void tty_audit_add_data(struct tty_struct *tty, unsigned char *data, size_t size) @@ -560,9 +560,10 @@ static inline void tty_audit_fork(struct signal_struct *sig) static inline void tty_audit_push(struct tty_struct *tty) { } -static inline void tty_audit_push_task(struct task_struct *tsk, - uid_t loginuid, u32 sessionid) +static inline int tty_audit_push_task(struct task_struct *tsk, + uid_t loginuid, u32 sessionid) { + return 0; } #endif -- cgit v1.2.3 From 65f8e441ed3c31c456aa70db1fbe50fb42079375 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Tue, 9 Nov 2010 10:48:25 +0000 Subject: tty: Fix formatting in tty.h Someone added a new ldisc number and messed up the tabbing. Fix it before anyone else copies it. Signed-off-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 2a754748dd5f..c7ea9bc8897c 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -50,7 +50,7 @@ #define N_V253 19 /* Codec control over voice modem */ #define N_CAIF 20 /* CAIF protocol for talking to modems */ #define N_GSM0710 21 /* GSM 0710 Mux */ -#define N_TI_WL 22 /* for TI's WL BT, FM, GPS combo chips */ +#define N_TI_WL 22 /* for TI's WL BT, FM, GPS combo chips */ /* * This character is the same as _POSIX_VDISABLE: it cannot be used as -- cgit v1.2.3 From 451a3c24b0135bce54542009b5fde43846c7cf67 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 17 Nov 2010 16:26:55 +0100 Subject: BKL: remove extraneous #include The big kernel lock has been removed from all these files at some point, leaving only the #include. Remove this too as a cleanup. Signed-off-by: Arnd Bergmann Signed-off-by: Linus Torvalds --- include/linux/tty.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index c7ea9bc8897c..032d79ff1d9d 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -13,7 +13,6 @@ #include #include #include -#include #include -- cgit v1.2.3 From acfa747baf73922021a047f2d87a2d866f5dbab5 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Mon, 29 Nov 2010 10:16:54 +0100 Subject: TTY: open/hangup race fixup Like in the "TTY: don't allow reopen when ldisc is changing" patch, this one fixes a TTY WARNING as described in the option 1) there: 1) __tty_hangup from tty_ldisc_hangup to tty_ldisc_enable. During this section tty_lock is held. However tty_lock is temporarily dropped in the middle of the function by tty_ldisc_hangup. The fix is to introduce a new flag which we set during the unlocked window and check it in tty_reopen too. The flag is TTY_HUPPING and is cleared after TTY_HUPPED is set. While at it, remove duplicate TTY_HUPPED set_bit. The one after calling ops->hangup seems to be more correct. But anyway, we hold tty_lock, so there should be no difference. Also document the function it does that kind of crap. Nicely reproducible with two forked children: static void do_work(const char *tty) { if (signal(SIGHUP, SIG_IGN) == SIG_ERR) exit(1); setsid(); while (1) { int fd = open(tty, O_RDWR|O_NOCTTY); if (fd < 0) continue; if (ioctl(fd, TIOCSCTTY)) continue; if (vhangup()) continue; close(fd); } exit(0); } Signed-off-by: Jiri Slaby Reported-by: Reported-by: Kyle McMartin Cc: Alan Cox Cc: stable Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index c7ea9bc8897c..021bfd2f0860 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -367,6 +367,7 @@ struct tty_file_private { #define TTY_HUPPED 18 /* Post driver->hangup() */ #define TTY_FLUSHING 19 /* Flushing to ldisc in progress */ #define TTY_FLUSHPENDING 20 /* Queued buffer flush pending */ +#define TTY_HUPPING 21 /* ->hangup() in progress */ #define TTY_WRITE_FLUSH(tty) tty_write_flush((tty)) -- cgit v1.2.3