From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755877Ab2EAQew (ORCPT ); Tue, 1 May 2012 12:34:52 -0400 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:54883 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753962Ab2EAQeu (ORCPT ); Tue, 1 May 2012 12:34:50 -0400 Date: Tue, 1 May 2012 17:37:39 +0100 From: Alan Cox To: linux-kernel@vger.kernel.org Subject: Killing the tty lock Message-ID: <20120501173739.4fe61fb5@pyramind.ukuu.org.uk> X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.8; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a first stab at it by making the lock per tty and using tty_mutex to cover the lookup for now. We ought to move to the lookup handing back ttys with a ref but thats a further step. It seems to mostly work but not quite reliably, so coul do with some more eyes and review for ideas. Alan commit 4a86662551c2b3f0b5e5119f7dd2623dd5fc2f7a Author: Alan Cox Date: Tue May 1 17:05:59 2012 +0100 tty_lock: Localise the lock In each remaining case the tty_lock is associated with a specific tty. This means we can now lock on a per tty basis. We do need tty_lock_pair() for the pty case. Uglier but still a step in the right direction. Signed-off-by: Alan Cox diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c index 24145c3..aa4f433 100644 --- a/drivers/tty/amiserial.c +++ b/drivers/tty/amiserial.c @@ -1033,7 +1033,7 @@ static int get_serial_info(struct tty_struct *tty, struct serial_state *state, if (!retinfo) return -EFAULT; memset(&tmp, 0, sizeof(tmp)); - tty_lock(); + tty_lock(tty); tmp.line = tty->index; tmp.port = state->port; tmp.flags = state->tport.flags; @@ -1042,7 +1042,7 @@ static int get_serial_info(struct tty_struct *tty, struct serial_state *state, tmp.close_delay = state->tport.close_delay; tmp.closing_wait = state->tport.closing_wait; tmp.custom_divisor = state->custom_divisor; - tty_unlock(); + tty_unlock(tty); if (copy_to_user(retinfo,&tmp,sizeof(*retinfo))) return -EFAULT; return 0; @@ -1059,12 +1059,12 @@ static int set_serial_info(struct tty_struct *tty, struct serial_state *state, if (copy_from_user(&new_serial,new_info,sizeof(new_serial))) return -EFAULT; - tty_lock(); + tty_lock(tty); change_spd = ((new_serial.flags ^ port->flags) & ASYNC_SPD_MASK) || new_serial.custom_divisor != state->custom_divisor; if (new_serial.irq || new_serial.port != state->port || new_serial.xmit_fifo_size != state->xmit_fifo_size) { - tty_unlock(); + tty_unlock(tty); return -EINVAL; } @@ -1082,7 +1082,7 @@ static int set_serial_info(struct tty_struct *tty, struct serial_state *state, } if (new_serial.baud_base < 9600) { - tty_unlock(); + tty_unlock(tty); return -EINVAL; } @@ -1114,7 +1114,7 @@ check_and_exit: } } else retval = startup(tty, state); - tty_unlock(); + tty_unlock(tty); return retval; } diff --git a/drivers/tty/cyclades.c b/drivers/tty/cyclades.c index e61cabd..6984e1a 100644 --- a/drivers/tty/cyclades.c +++ b/drivers/tty/cyclades.c @@ -1599,7 +1599,7 @@ static int cy_open(struct tty_struct *tty, struct file *filp) * If the port is the middle of closing, bail out now */ if (tty_hung_up_p(filp) || (info->port.flags & ASYNC_CLOSING)) { - wait_event_interruptible_tty(info->port.close_wait, + wait_event_interruptible_tty(tty, info->port.close_wait, !(info->port.flags & ASYNC_CLOSING)); return (info->port.flags & ASYNC_HUP_NOTIFY) ? -EAGAIN: -ERESTARTSYS; } diff --git a/drivers/tty/n_r3964.c b/drivers/tty/n_r3964.c index 5c6c314..656ad93 100644 --- a/drivers/tty/n_r3964.c +++ b/drivers/tty/n_r3964.c @@ -1065,7 +1065,8 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file, TRACE_L("read()"); - tty_lock(); + /* FIXME: should use a private lock */ + tty_lock(tty); pClient = findClient(pInfo, task_pid(current)); if (pClient) { @@ -1077,7 +1078,7 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file, goto unlock; } /* block until there is a message: */ - wait_event_interruptible_tty(pInfo->read_wait, + wait_event_interruptible_tty(tty, pInfo->read_wait, (pMsg = remove_msg(pInfo, pClient))); } @@ -1107,7 +1108,7 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file, } ret = -EPERM; unlock: - tty_unlock(); + tty_unlock(tty); return ret; } @@ -1156,7 +1157,7 @@ static ssize_t r3964_write(struct tty_struct *tty, struct file *file, pHeader->locks = 0; pHeader->owner = NULL; - tty_lock(); + tty_lock(tty); pClient = findClient(pInfo, task_pid(current)); if (pClient) { @@ -1175,7 +1176,7 @@ static ssize_t r3964_write(struct tty_struct *tty, struct file *file, add_tx_queue(pInfo, pHeader); trigger_transmit(pInfo); - tty_unlock(); + tty_unlock(tty); return 0; } diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index 5505ffc..c2d938f 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -47,6 +47,7 @@ static void pty_close(struct tty_struct *tty, struct file *filp) wake_up_interruptible(&tty->read_wait); wake_up_interruptible(&tty->write_wait); tty->packet = 0; + /* Review - krefs on tty_link ?? */ if (!tty->link) return; tty->link->packet = 0; @@ -62,9 +63,7 @@ static void pty_close(struct tty_struct *tty, struct file *filp) mutex_unlock(&devpts_mutex); } #endif - tty_unlock(); tty_vhangup(tty->link); - tty_lock(); } } @@ -622,9 +621,9 @@ static int ptmx_open(struct inode *inode, struct file *filp) return retval; /* find a device that is not in use. */ - tty_lock(); + mutex_lock(&devpts_mutex); index = devpts_new_index(inode); - tty_unlock(); + mutex_unlock(&devpts_mutex); if (index < 0) { retval = index; goto err_file; @@ -634,7 +633,8 @@ static int ptmx_open(struct inode *inode, struct file *filp) mutex_lock(&devpts_mutex); tty = tty_init_dev(ptm_driver, index); mutex_unlock(&devpts_mutex); - tty_lock(); + /* Must take this under the tty_mutex until lookups keep a kref */ + tty_lock(tty); mutex_unlock(&tty_mutex); if (IS_ERR(tty)) { @@ -654,15 +654,17 @@ static int ptmx_open(struct inode *inode, struct file *filp) if (retval) goto err_release; - tty_unlock(); + tty_unlock(tty); return 0; err_release: - tty_unlock(); + tty_unlock(tty); tty_release(inode, filp); return retval; out: + mutex_lock(&devpts_mutex); devpts_kill_index(inode, index); - tty_unlock(); + mutex_unlock(&devpts_mutex); + tty_unlock(tty); err_file: tty_free_file(filp); return retval; diff --git a/drivers/tty/synclink.c b/drivers/tty/synclink.c index 593d40a..5ed0daa 100644 --- a/drivers/tty/synclink.c +++ b/drivers/tty/synclink.c @@ -3338,9 +3338,9 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp, printk("%s(%d):block_til_ready blocking on %s count=%d\n", __FILE__,__LINE__, tty->driver->name, port->count ); - tty_unlock(); + tty_unlock(tty); schedule(); - tty_lock(); + tty_lock(tty); } set_current_state(TASK_RUNNING); diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c index aa1debf..45b43f1 100644 --- a/drivers/tty/synclink_gt.c +++ b/drivers/tty/synclink_gt.c @@ -3336,9 +3336,9 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp, } DBGINFO(("%s block_til_ready wait\n", tty->driver->name)); - tty_unlock(); + tty_unlock(tty); schedule(); - tty_lock(); + tty_lock(tty); } set_current_state(TASK_RUNNING); diff --git a/drivers/tty/synclinkmp.c b/drivers/tty/synclinkmp.c index a3dddc1..4a1e4f0 100644 --- a/drivers/tty/synclinkmp.c +++ b/drivers/tty/synclinkmp.c @@ -3357,9 +3357,9 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp, printk("%s(%d):%s block_til_ready() count=%d\n", __FILE__,__LINE__, tty->driver->name, port->count ); - tty_unlock(); + tty_unlock(tty); schedule(); - tty_lock(); + tty_lock(tty); } set_current_state(TASK_RUNNING); diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index b425c79..1ca0629 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -573,7 +573,7 @@ void __tty_hangup(struct tty_struct *tty) } spin_unlock(&redirect_lock); - tty_lock(); + tty_lock(tty); /* some functions below drop BTM, so we need this bit */ set_bit(TTY_HUPPING, &tty->flags); @@ -666,7 +666,7 @@ void __tty_hangup(struct tty_struct *tty) clear_bit(TTY_HUPPING, &tty->flags); tty_ldisc_enable(tty); - tty_unlock(); + tty_unlock(tty); if (f) fput(f); @@ -1103,12 +1103,12 @@ void tty_write_message(struct tty_struct *tty, char *msg) { if (tty) { mutex_lock(&tty->atomic_write_lock); - tty_lock(); + tty_lock(tty); if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) { - tty_unlock(); + tty_unlock(tty); tty->ops->write(tty, msg, strlen(msg)); } else - tty_unlock(); + tty_unlock(tty); tty_write_unlock(tty); } return; @@ -1403,6 +1403,7 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx) } initialize_tty_struct(tty, driver, idx); + tty_lock(tty); retval = tty_driver_install_tty(driver, tty); if (retval < 0) goto err_deinit_tty; @@ -1418,6 +1419,7 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx) return tty; err_deinit_tty: + tty_unlock(tty); deinitialize_tty_struct(tty); free_tty_struct(tty); err_module_put: @@ -1426,6 +1428,7 @@ err_module_put: /* call the tty release_tty routine to clean out this slot */ err_release_tty: + tty_unlock(tty); printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, " "clearing slot %d\n", idx); release_tty(tty, idx); @@ -1628,7 +1631,7 @@ int tty_release(struct inode *inode, struct file *filp) if (tty_paranoia_check(tty, inode, __func__)) return 0; - tty_lock(); + tty_lock(tty); check_tty_count(tty, __func__); __tty_fasync(-1, filp, 0); @@ -1637,10 +1640,11 @@ int tty_release(struct inode *inode, struct file *filp) pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_MASTER); devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; + /* Review: parallel close */ o_tty = tty->link; if (tty_release_checks(tty, o_tty, idx)) { - tty_unlock(); + tty_unlock(tty); return 0; } @@ -1652,7 +1656,7 @@ int tty_release(struct inode *inode, struct file *filp) if (tty->ops->close) tty->ops->close(tty, filp); - tty_unlock(); + tty_unlock(tty); /* * Sanity check: if tty->count is going to zero, there shouldn't be * any waiters on tty->read_wait or tty->write_wait. We test the @@ -1675,7 +1679,7 @@ int tty_release(struct inode *inode, struct file *filp) opens on /dev/tty */ mutex_lock(&tty_mutex); - tty_lock(); + tty_lock_pair(tty, o_tty); tty_closing = tty->count <= 1; o_tty_closing = o_tty && (o_tty->count <= (pty_master ? 1 : 0)); @@ -1706,7 +1710,7 @@ int tty_release(struct inode *inode, struct file *filp) printk(KERN_WARNING "%s: %s: read/write wait queue active!\n", __func__, tty_name(tty, buf)); - tty_unlock(); + tty_unlock_pair(tty, o_tty); mutex_unlock(&tty_mutex); schedule(); } @@ -1769,7 +1773,7 @@ int tty_release(struct inode *inode, struct file *filp) /* check whether both sides are closing ... */ if (!tty_closing || (o_tty && !o_tty_closing)) { - tty_unlock(); + tty_unlock_pair(tty, o_tty); return 0; } @@ -1789,7 +1793,7 @@ int tty_release(struct inode *inode, struct file *filp) /* Make this pty number available for reallocation */ if (devpts) devpts_kill_index(inode, idx); - tty_unlock(); + tty_unlock_pair(tty, o_tty); return 0; } @@ -1893,6 +1897,9 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp, * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev. * tty->count should protect the rest. * ->siglock protects ->signal/->sighand + * + * Note: the tty_unlock/lock cases without a ref are only safe due to + * tty_mutex */ static int tty_open(struct inode *inode, struct file *filp) @@ -1916,8 +1923,7 @@ retry_open: retval = 0; mutex_lock(&tty_mutex); - tty_lock(); - + /* This is protected by the tty_mutex */ tty = tty_open_current_tty(device, filp); if (IS_ERR(tty)) { retval = PTR_ERR(tty); @@ -1938,17 +1944,19 @@ retry_open: } if (tty) { + tty_lock(tty); retval = tty_reopen(tty); - if (retval) + if (retval < 0) { + tty_unlock(tty); tty = ERR_PTR(retval); - } else + } + } else /* Returns with the tty_lock held for now */ tty = tty_init_dev(driver, index); mutex_unlock(&tty_mutex); if (driver) tty_driver_kref_put(driver); if (IS_ERR(tty)) { - tty_unlock(); retval = PTR_ERR(tty); goto err_file; } @@ -1977,7 +1985,7 @@ retry_open: printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__, retval, tty->name); #endif - tty_unlock(); /* need to call tty_release without BTM */ + tty_unlock(tty); /* need to call tty_release without BTM */ tty_release(inode, filp); if (retval != -ERESTARTSYS) return retval; @@ -1989,17 +1997,17 @@ retry_open: /* * Need to reset f_op in case a hangup happened. */ - tty_lock(); + tty_lock(tty); if (filp->f_op == &hung_up_tty_fops) filp->f_op = &tty_fops; - tty_unlock(); + tty_unlock(tty); goto retry_open; } - tty_unlock(); + tty_unlock(tty); mutex_lock(&tty_mutex); - tty_lock(); + tty_lock(tty); spin_lock_irq(¤t->sighand->siglock); if (!noctty && current->signal->leader && @@ -2007,11 +2015,10 @@ retry_open: tty->session == NULL) __proc_set_tty(current, tty); spin_unlock_irq(¤t->sighand->siglock); - tty_unlock(); + tty_unlock(tty); mutex_unlock(&tty_mutex); return 0; err_unlock: - tty_unlock(); mutex_unlock(&tty_mutex); /* after locks to avoid deadlock */ if (!IS_ERR_OR_NULL(driver)) @@ -2094,10 +2101,13 @@ out: static int tty_fasync(int fd, struct file *filp, int on) { + struct tty_struct *tty = file_tty(filp); int retval; - tty_lock(); + + tty_lock(tty); retval = __tty_fasync(fd, filp, on); - tty_unlock(); + tty_unlock(tty); + return retval; } @@ -2934,6 +2944,7 @@ void initialize_tty_struct(struct tty_struct *tty, tty->pgrp = NULL; tty->overrun_time = jiffies; tty_buffer_init(tty); + mutex_init(&tty->legacy_mutex); mutex_init(&tty->termios_mutex); mutex_init(&tty->ldisc_mutex); init_waitqueue_head(&tty->write_wait); diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index 24b95db..fa65cde 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -567,7 +567,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) if (IS_ERR(new_ldisc)) return PTR_ERR(new_ldisc); - tty_lock(); + tty_lock(tty); /* * We need to look at the tty locking here for pty/tty pairs * when both sides try to change in parallel. @@ -581,12 +581,12 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) */ if (tty->ldisc->ops->num == ldisc) { - tty_unlock(); + tty_unlock(tty); tty_ldisc_put(new_ldisc); return 0; } - tty_unlock(); + tty_unlock(tty); /* * Problem: What do we do if this blocks ? * We could deadlock here @@ -594,7 +594,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) tty_wait_until_sent(tty, 0); - tty_lock(); + tty_lock(tty); mutex_lock(&tty->ldisc_mutex); /* @@ -604,10 +604,10 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) while (test_bit(TTY_LDISC_CHANGING, &tty->flags)) { mutex_unlock(&tty->ldisc_mutex); - tty_unlock(); + tty_unlock(tty); wait_event(tty_ldisc_wait, test_bit(TTY_LDISC_CHANGING, &tty->flags) == 0); - tty_lock(); + tty_lock(tty); mutex_lock(&tty->ldisc_mutex); } @@ -622,7 +622,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) o_ldisc = tty->ldisc; - tty_unlock(); + tty_unlock(tty); /* * Make sure we don't change while someone holds a * reference to the line discipline. The TTY_LDISC bit @@ -649,7 +649,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) retval = tty_ldisc_wait_idle(tty, 5 * HZ); - tty_lock(); + tty_lock(tty); mutex_lock(&tty->ldisc_mutex); /* handle wait idle failure locked */ @@ -664,7 +664,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) clear_bit(TTY_LDISC_CHANGING, &tty->flags); mutex_unlock(&tty->ldisc_mutex); tty_ldisc_put(new_ldisc); - tty_unlock(); + tty_unlock(tty); return -EIO; } @@ -707,7 +707,7 @@ enable: if (o_work) schedule_work(&o_tty->buf.work); mutex_unlock(&tty->ldisc_mutex); - tty_unlock(); + tty_unlock(tty); return retval; } @@ -815,11 +815,11 @@ void tty_ldisc_hangup(struct tty_struct *tty) * need to wait for another function taking the BTM */ clear_bit(TTY_LDISC, &tty->flags); - tty_unlock(); + tty_unlock(tty); cancel_work_sync(&tty->buf.work); mutex_unlock(&tty->ldisc_mutex); retry: - tty_lock(); + tty_lock(tty); mutex_lock(&tty->ldisc_mutex); /* At this point we have a closed ldisc and we want to @@ -830,7 +830,7 @@ retry: if (atomic_read(&tty->ldisc->users) != 1) { char cur_n[TASK_COMM_LEN], tty_n[64]; long timeout = 3 * HZ; - tty_unlock(); + tty_unlock(tty); while (tty_ldisc_wait_idle(tty, timeout) == -EBUSY) { timeout = MAX_SCHEDULE_TIMEOUT; @@ -911,10 +911,10 @@ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty) * race with the set_ldisc code path. */ - tty_unlock(); + tty_unlock(tty); tty_ldisc_halt(tty); tty_ldisc_flush_works(tty); - tty_lock(); + tty_lock(tty); mutex_lock(&tty->ldisc_mutex); /* diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c index 9ff986c..7664b10 100644 --- a/drivers/tty/tty_mutex.c +++ b/drivers/tty/tty_mutex.c @@ -4,29 +4,56 @@ #include #include -/* - * The 'big tty mutex' - * - * This mutex is taken and released by tty_lock() and tty_unlock(), - * replacing the older big kernel lock. - * It can no longer be taken recursively, and does not get - * released implicitly while sleeping. - * - * Don't use in new code. - */ -static DEFINE_MUTEX(big_tty_mutex); +/* Legacy tty mutex glue */ /* * Getting the big tty mutex. */ -void __lockfunc tty_lock(void) + +void __lockfunc tty_lock(struct tty_struct *tty) { - mutex_lock(&big_tty_mutex); + if (mutex_is_locked(&tty->legacy_mutex)) { + WARN_ON(1); + return; + } + mutex_lock(&tty->legacy_mutex); } EXPORT_SYMBOL(tty_lock); -void __lockfunc tty_unlock(void) +void __lockfunc tty_unlock(struct tty_struct *tty) { - mutex_unlock(&big_tty_mutex); + if (!mutex_is_locked(&tty->legacy_mutex)) { + WARN_ON(1); + return; + } + mutex_unlock(&tty->legacy_mutex); } EXPORT_SYMBOL(tty_unlock); + +/* + * Getting the big tty mutex for a pair of ttys with lock ordering + * On a non pty/tty pair tty2 can be NULL which is just fine. + */ +void __lockfunc tty_lock_pair(struct tty_struct *tty, + struct tty_struct *tty2) +{ + if (tty < tty2) { + tty_lock(tty); + tty_lock(tty2); + } else { + if (tty2 && tty2 != tty) + tty_lock(tty2); + tty_lock(tty); + } +} +EXPORT_SYMBOL(tty_lock_pair); + +void __lockfunc tty_unlock_pair(struct tty_struct *tty, + struct tty_struct *tty2) +{ + tty_unlock(tty); + if (tty2 && tty2 != tty) + tty_unlock(tty2); +} +EXPORT_SYMBOL(tty_unlock_pair); + diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c index bf6e238..d9cca95 100644 --- a/drivers/tty/tty_port.c +++ b/drivers/tty/tty_port.c @@ -230,7 +230,7 @@ int tty_port_block_til_ready(struct tty_port *port, /* block if port is in the process of being closed */ if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) { - wait_event_interruptible_tty(port->close_wait, + wait_event_interruptible_tty(tty, port->close_wait, !(port->flags & ASYNC_CLOSING)); if (port->flags & ASYNC_HUP_NOTIFY) return -EAGAIN; @@ -296,9 +296,9 @@ int tty_port_block_til_ready(struct tty_port *port, retval = -ERESTARTSYS; break; } - tty_unlock(); + tty_unlock(tty); schedule(); - tty_lock(); + tty_lock(tty); } finish_wait(&port->open_wait, &wait); diff --git a/include/linux/tty.h b/include/linux/tty.h index 9f47ab5..4990ef2 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -268,6 +268,7 @@ struct tty_struct { struct mutex ldisc_mutex; struct tty_ldisc *ldisc; + struct mutex legacy_mutex; struct mutex termios_mutex; spinlock_t ctrl_lock; /* Termios values are protected by the termios mutex */ @@ -605,8 +606,12 @@ extern long vt_compat_ioctl(struct tty_struct *tty, /* tty_mutex.c */ /* functions for preparation of BKL removal */ -extern void __lockfunc tty_lock(void) __acquires(tty_lock); -extern void __lockfunc tty_unlock(void) __releases(tty_lock); +extern void __lockfunc tty_lock(struct tty_struct *tty); +extern void __lockfunc tty_unlock(struct tty_struct *tty); +extern void __lockfunc tty_lock_pair(struct tty_struct *tty, + struct tty_struct *tty2); +extern void __lockfunc tty_unlock_pair(struct tty_struct *tty, + struct tty_struct *tty2); /* * this shall be called only from where BTM is held (like close) @@ -621,9 +626,9 @@ extern void __lockfunc tty_unlock(void) __releases(tty_lock); static inline void tty_wait_until_sent_from_close(struct tty_struct *tty, long timeout) { - tty_unlock(); /* tty->ops->close holds the BTM, drop it while waiting */ + tty_unlock(tty); /* tty->ops->close holds the BTM, drop it while waiting */ tty_wait_until_sent(tty, timeout); - tty_lock(); + tty_lock(tty); } /* @@ -638,16 +643,16 @@ static inline void tty_wait_until_sent_from_close(struct tty_struct *tty, * * Do not use in new code. */ -#define wait_event_interruptible_tty(wq, condition) \ +#define wait_event_interruptible_tty(tty, wq, condition) \ ({ \ int __ret = 0; \ if (!(condition)) { \ - __wait_event_interruptible_tty(wq, condition, __ret); \ + __wait_event_interruptible_tty(tty, wq, condition, __ret); \ } \ __ret; \ }) -#define __wait_event_interruptible_tty(wq, condition, ret) \ +#define __wait_event_interruptible_tty(tty, wq, condition, ret) \ do { \ DEFINE_WAIT(__wait); \ \ @@ -656,9 +661,9 @@ do { \ if (condition) \ break; \ if (!signal_pending(current)) { \ - tty_unlock(); \ + tty_unlock(tty); \ schedule(); \ - tty_lock(); \ + tty_lock(tty); \ continue; \ } \ ret = -ERESTARTSYS; \