diff options
Diffstat (limited to 'drivers/tty/tty_buffer.c')
| -rw-r--r-- | drivers/tty/tty_buffer.c | 31 |
1 files changed, 4 insertions, 27 deletions
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 5d5a56407aa8..685757c6ce87 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -62,8 +62,6 @@ static void tty_buffer_reset(struct tty_buffer *p, size_t size) * * Remove all the buffers pending on a tty whether queued with data * or in the free ring. Must be called when the tty is no longer in use - * - * Locking: none */ void tty_buffer_free_all(struct tty_port *port) @@ -216,29 +214,26 @@ void tty_buffer_flush(struct tty_struct *tty) * * Make at least size bytes of linear space available for the tty * buffer. If we fail return the size we managed to find. - * - * Locking: Takes port->buf.lock */ int tty_buffer_request_room(struct tty_port *port, size_t size) { struct tty_bufhead *buf = &port->buf; struct tty_buffer *b, *n; int left; - unsigned long flags; - spin_lock_irqsave(&buf->lock, flags); + b = buf->tail; left = b->size - b->used; if (left < size) { /* This is the slow path - looking for new buffers to use */ if ((n = tty_buffer_alloc(port, size)) != NULL) { - b->next = n; - b->commit = b->used; buf->tail = n; + b->commit = b->used; + smp_mb(); + b->next = n; } else size = left; } - spin_unlock_irqrestore(&buf->lock, flags); return size; } EXPORT_SYMBOL_GPL(tty_buffer_request_room); @@ -252,8 +247,6 @@ EXPORT_SYMBOL_GPL(tty_buffer_request_room); * * Queue a series of bytes to the tty buffering. All the characters * passed are marked with the supplied flag. Returns the number added. - * - * Locking: Called functions may take port->buf.lock */ int tty_insert_flip_string_fixed_flag(struct tty_port *port, @@ -288,8 +281,6 @@ EXPORT_SYMBOL(tty_insert_flip_string_fixed_flag); * Queue a series of bytes to the tty buffering. For each character * the flags array indicates the status of the character. Returns the * number added. - * - * Locking: Called functions may take port->buf.lock */ int tty_insert_flip_string_flags(struct tty_port *port, @@ -324,19 +315,14 @@ EXPORT_SYMBOL(tty_insert_flip_string_flags); * processing by the line discipline. * Note that this function can only be used when the low_latency flag * is unset. Otherwise the workqueue won't be flushed. - * - * Locking: Takes port->buf.lock */ void tty_schedule_flip(struct tty_port *port) { struct tty_bufhead *buf = &port->buf; - unsigned long flags; WARN_ON(port->low_latency); - spin_lock_irqsave(&buf->lock, flags); buf->tail->commit = buf->tail->used; - spin_unlock_irqrestore(&buf->lock, flags); schedule_work(&buf->work); } EXPORT_SYMBOL(tty_schedule_flip); @@ -352,8 +338,6 @@ EXPORT_SYMBOL(tty_schedule_flip); * accounted for as ready for normal characters. This is used for drivers * that need their own block copy routines into the buffer. There is no * guarantee the buffer is a DMA target! - * - * Locking: May call functions taking port->buf.lock */ int tty_prepare_flip_string(struct tty_port *port, unsigned char **chars, @@ -382,8 +366,6 @@ EXPORT_SYMBOL_GPL(tty_prepare_flip_string); * accounted for as ready for characters. This is used for drivers * that need their own block copy routines into the buffer. There is no * guarantee the buffer is a DMA target! - * - * Locking: May call functions taking port->buf.lock */ int tty_prepare_flip_string_flags(struct tty_port *port, @@ -511,18 +493,13 @@ void tty_flush_to_ldisc(struct tty_struct *tty) * * In the event of the queue being busy for flipping the work will be * held off and retried later. - * - * Locking: tty buffer lock. Driver locks in low latency mode. */ void tty_flip_buffer_push(struct tty_port *port) { struct tty_bufhead *buf = &port->buf; - unsigned long flags; - spin_lock_irqsave(&buf->lock, flags); buf->tail->commit = buf->tail->used; - spin_unlock_irqrestore(&buf->lock, flags); if (port->low_latency) flush_to_ldisc(&buf->work); |