]> err.no Git - linux-2.6/blobdiff - drivers/char/tty_io.c
[Blackfin] arch: Add proper SW System Reset delay sequence
[linux-2.6] / drivers / char / tty_io.c
index de37ebc3a4cf03fa9e94d68fbf7e0f70b9293337..f36fecd3fd264a67cf7d66b2fd8e74369a38f406 100644 (file)
 #include <linux/selection.h>
 
 #include <linux/kmod.h>
+#include <linux/nsproxy.h>
 
 #undef TTY_DEBUG_HANGUP
 
@@ -369,25 +370,54 @@ static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)
 }
 
 /**
- *     tty_buffer_flush                -       flush full tty buffers
+ *     __tty_buffer_flush              -       flush full tty buffers
  *     @tty: tty to flush
  *
- *     flush all the buffers containing receive data
+ *     flush all the buffers containing receive data. Caller must
+ *     hold the buffer lock and must have ensured no parallel flush to
+ *     ldisc is running.
  *
- *     Locking: none
+ *     Locking: Caller must hold tty->buf.lock
  */
 
-static void tty_buffer_flush(struct tty_struct *tty)
+static void __tty_buffer_flush(struct tty_struct *tty)
 {
        struct tty_buffer *thead;
-       unsigned long flags;
 
-       spin_lock_irqsave(&tty->buf.lock, flags);
        while((thead = tty->buf.head) != NULL) {
                tty->buf.head = thead->next;
                tty_buffer_free(tty, thead);
        }
        tty->buf.tail = NULL;
+}
+
+/**
+ *     tty_buffer_flush                -       flush full tty buffers
+ *     @tty: tty to flush
+ *
+ *     flush all the buffers containing receive data. If the buffer is
+ *     being processed by flush_to_ldisc then we defer the processing
+ *     to that function
+ *
+ *     Locking: none
+ */
+
+static void tty_buffer_flush(struct tty_struct *tty)
+{
+       unsigned long flags;
+       spin_lock_irqsave(&tty->buf.lock, flags);
+
+       /* If the data is being pushed to the tty layer then we can't
+          process it here. Instead set a flag and the flush_to_ldisc
+          path will process the flush request before it exits */
+       if (test_bit(TTY_FLUSHING, &tty->flags)) {
+               set_bit(TTY_FLUSHPENDING, &tty->flags);
+               spin_unlock_irqrestore(&tty->buf.lock, flags);
+               wait_event(tty->read_wait,
+                               test_bit(TTY_FLUSHPENDING, &tty->flags) == 0);
+               return;
+       } else
+               __tty_buffer_flush(tty);
        spin_unlock_irqrestore(&tty->buf.lock, flags);
 }
 
@@ -913,7 +943,7 @@ EXPORT_SYMBOL_GPL(tty_ldisc_deref);
  *     @tty: terminal to activate ldisc on
  *
  *     Set the TTY_LDISC flag when the line discipline can be called
- *     again. Do neccessary wakeups for existing sleepers.
+ *     again. Do necessary wakeups for existing sleepers.
  *
  *     Note: nobody should set this bit except via this function. Clearing
  *     directly is allowed.
@@ -1474,7 +1504,7 @@ EXPORT_SYMBOL(tty_hangup);
  *
  *     The user has asked via system call for the terminal to be hung up.
  *     We do this synchronously so that when the syscall returns the process
- *     is complete. That guarantee is neccessary for security reasons.
+ *     is complete. That guarantee is necessary for security reasons.
  */
 
 void tty_vhangup(struct tty_struct * tty)
@@ -1661,7 +1691,7 @@ EXPORT_SYMBOL(stop_tty);
  *     @tty: tty to start
  *
  *     Start a tty that has been stopped if at all possible. Perform
- *     any neccessary wakeups and propagate the TIOCPKT status. If this
+ *     any necessary wakeups and propagate the TIOCPKT status. If this
  *     is the tty was previous stopped and is being started then the
  *     driver start method is invoked and the line discipline woken.
  *
@@ -2034,8 +2064,7 @@ static int init_dev(struct tty_driver *driver, int idx,
        }
 
        if (!*tp_loc) {
-               tp = (struct ktermios *) kmalloc(sizeof(struct ktermios),
-                                               GFP_KERNEL);
+               tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
                if (!tp)
                        goto free_mem_out;
                *tp = driver->init_termios;
@@ -2065,8 +2094,7 @@ static int init_dev(struct tty_driver *driver, int idx,
                }
 
                if (!*o_tp_loc) {
-                       o_tp = (struct ktermios *)
-                               kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+                       o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
                        if (!o_tp)
                                goto free_mem_out;
                        *o_tp = driver->other->init_termios;
@@ -2849,7 +2877,7 @@ static int tty_fasync(int fd, struct file * filp, int on)
  *     @tty: tty to fake input into
  *     @p: pointer to character
  *
- *     Fake input to a tty device. Does the neccessary locking and
+ *     Fake input to a tty device. Does the necessary locking and
  *     input management.
  *
  *     FIXME: does not honour flow control ??
@@ -3080,7 +3108,7 @@ static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
         */
        if (tty == real_tty && current->signal->tty != real_tty)
                return -ENOTTY;
-       return put_user(pid_nr(real_tty->pgrp), p);
+       return put_user(pid_vnr(real_tty->pgrp), p);
 }
 
 /**
@@ -3114,7 +3142,7 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
        if (pgrp_nr < 0)
                return -EINVAL;
        rcu_read_lock();
-       pgrp = find_pid(pgrp_nr);
+       pgrp = find_vpid(pgrp_nr);
        retval = -ESRCH;
        if (!pgrp)
                goto out_unlock;
@@ -3151,7 +3179,7 @@ static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t _
                return -ENOTTY;
        if (!real_tty->session)
                return -ENOTTY;
-       return put_user(pid_nr(real_tty->session), p);
+       return put_user(pid_vnr(real_tty->session), p);
 }
 
 /**
@@ -3501,8 +3529,8 @@ void __do_SAK(struct tty_struct *tty)
        /* Kill the entire session */
        do_each_pid_task(session, PIDTYPE_SID, p) {
                printk(KERN_NOTICE "SAK: killed process %d"
-                       " (%s): process_session(p)==tty->session\n",
-                       p->pid, p->comm);
+                       " (%s): task_session_nr(p)==tty->session\n",
+                       task_pid_nr(p), p->comm);
                send_sig(SIGKILL, p, 1);
        } while_each_pid_task(session, PIDTYPE_SID, p);
        /* Now kill any processes that happen to have the
@@ -3511,8 +3539,8 @@ void __do_SAK(struct tty_struct *tty)
        do_each_thread(g, p) {
                if (p->signal->tty == tty) {
                        printk(KERN_NOTICE "SAK: killed process %d"
-                           " (%s): process_session(p)==tty->session\n",
-                           p->pid, p->comm);
+                           " (%s): task_session_nr(p)==tty->session\n",
+                           task_pid_nr(p), p->comm);
                        send_sig(SIGKILL, p, 1);
                        continue;
                }
@@ -3532,7 +3560,7 @@ void __do_SAK(struct tty_struct *tty)
                                    filp->private_data == tty) {
                                        printk(KERN_NOTICE "SAK: killed process %d"
                                            " (%s): fd#%d opened to the tty\n",
-                                           p->pid, p->comm, i);
+                                           task_pid_nr(p), p->comm, i);
                                        force_sig(SIGKILL, p);
                                        break;
                                }
@@ -3594,6 +3622,7 @@ static void flush_to_ldisc(struct work_struct *work)
                return;
 
        spin_lock_irqsave(&tty->buf.lock, flags);
+       set_bit(TTY_FLUSHING, &tty->flags);     /* So we know a flush is running */
        head = tty->buf.head;
        if (head != NULL) {
                tty->buf.head = NULL;
@@ -3607,6 +3636,11 @@ static void flush_to_ldisc(struct work_struct *work)
                                tty_buffer_free(tty, tbuf);
                                continue;
                        }
+                       /* Ldisc or user is trying to flush the buffers
+                          we are feeding to the ldisc, stop feeding the
+                          line discipline as we want to empty the queue */
+                       if (test_bit(TTY_FLUSHPENDING, &tty->flags))
+                               break;
                        if (!tty->receive_room) {
                                schedule_delayed_work(&tty->buf.work, 1);
                                break;
@@ -3620,8 +3654,17 @@ static void flush_to_ldisc(struct work_struct *work)
                        disc->receive_buf(tty, char_buf, flag_buf, count);
                        spin_lock_irqsave(&tty->buf.lock, flags);
                }
+               /* Restore the queue head */
                tty->buf.head = head;
        }
+       /* We may have a deferred request to flush the input buffer,
+          if so pull the chain under the lock and empty the queue */
+       if (test_bit(TTY_FLUSHPENDING, &tty->flags)) {
+               __tty_buffer_flush(tty);
+               clear_bit(TTY_FLUSHPENDING, &tty->flags);
+               wake_up(&tty->read_wait);
+       }
+       clear_bit(TTY_FLUSHING, &tty->flags);
        spin_unlock_irqrestore(&tty->buf.lock, flags);
 
        tty_ldisc_deref(disc);