diff options
author | Peter Hurley <peter@hurleysoftware.com> | 2013-06-15 15:36:11 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-07-24 01:47:09 +0200 |
commit | d7a68be4f265be10e24be931c257af30ca55566b (patch) | |
tree | c60c359eb4398fae7687320fd2c89220916b9cb9 /drivers/tty/tty_buffer.c | |
parent | tty: Ensure single-threaded flip buffer consumer with mutex (diff) | |
download | linux-d7a68be4f265be10e24be931c257af30ca55566b.tar.xz linux-d7a68be4f265be10e24be931c257af30ca55566b.zip |
tty: Only perform flip buffer flush from tty_buffer_flush()
Now that dropping the buffer lock is not necessary (as result of
converting the spin lock to a mutex), the flip buffer flush no
longer needs to be handled by the buffer work.
Simply signal a flush is required; the buffer work will exit the
i/o loop, which allows tty_buffer_flush() to proceed.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_buffer.c')
-rw-r--r-- | drivers/tty/tty_buffer.c | 63 |
1 files changed, 21 insertions, 42 deletions
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index c3c606c52722..39cae611fe59 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -189,19 +189,11 @@ void tty_buffer_flush(struct tty_struct *tty) struct tty_port *port = tty->port; struct tty_bufhead *buf = &port->buf; - mutex_lock(&buf->flush_mutex); - /* 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(TTYP_FLUSHING, &port->iflags)) { - set_bit(TTYP_FLUSHPENDING, &port->iflags); - mutex_unlock(&buf->flush_mutex); - wait_event(tty->read_wait, - test_bit(TTYP_FLUSHPENDING, &port->iflags) == 0); - return; - } + set_bit(TTYP_FLUSHPENDING, &port->iflags); + mutex_lock(&buf->flush_mutex); __tty_buffer_flush(port); + clear_bit(TTYP_FLUSHPENDING, &port->iflags); mutex_unlock(&buf->flush_mutex); } @@ -429,39 +421,26 @@ static void flush_to_ldisc(struct work_struct *work) mutex_lock(&buf->flush_mutex); - if (!test_and_set_bit(TTYP_FLUSHING, &port->iflags)) { - while (1) { - struct tty_buffer *head = buf->head; - int count; - - count = head->commit - head->read; - if (!count) { - if (head->next == NULL) - break; - buf->head = head->next; - tty_buffer_free(port, head); - continue; - } - - mutex_unlock(&buf->flush_mutex); - - count = receive_buf(tty, head, count); - - mutex_lock(&buf->flush_mutex); - - /* Ldisc or user is trying to flush the buffers. - 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(TTYP_FLUSHPENDING, &port->iflags)) { - __tty_buffer_flush(port); - clear_bit(TTYP_FLUSHPENDING, &port->iflags); - wake_up(&tty->read_wait); - break; - } else if (!count) + while (1) { + struct tty_buffer *head = buf->head; + int count; + + /* Ldisc or user is trying to flush the buffers. */ + if (test_bit(TTYP_FLUSHPENDING, &port->iflags)) + break; + + count = head->commit - head->read; + if (!count) { + if (head->next == NULL) break; + buf->head = head->next; + tty_buffer_free(port, head); + continue; } - clear_bit(TTYP_FLUSHING, &port->iflags); + + count = receive_buf(tty, head, count); + if (!count) + break; } mutex_unlock(&buf->flush_mutex); |