From 0f56bd2f6a97d8b0eb5c8f9bc04b83a6c16d1d48 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 15 Jun 2013 09:36:13 -0400 Subject: [PATCH] tty: Use non-atomic state to signal flip buffer flush pending Atomic bit ops are no longer required to indicate a flip buffer flush is pending, as the flush_mutex is sufficient barrier. Remove the unnecessary port .iflags field and localize flip buffer state to struct tty_bufhead. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_buffer.c | 7 ++++--- include/linux/tty.h | 3 +-- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 39cae61..fb042b9 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -189,11 +189,11 @@ void tty_buffer_flush(struct tty_struct *tty) struct tty_port *port = tty->port; struct tty_bufhead *buf = &port->buf; - set_bit(TTYP_FLUSHPENDING, &port->iflags); + buf->flushpending = 1; mutex_lock(&buf->flush_mutex); __tty_buffer_flush(port); - clear_bit(TTYP_FLUSHPENDING, &port->iflags); + buf->flushpending = 0; mutex_unlock(&buf->flush_mutex); } @@ -426,7 +426,7 @@ static void flush_to_ldisc(struct work_struct *work) int count; /* Ldisc or user is trying to flush the buffers. */ - if (test_bit(TTYP_FLUSHPENDING, &port->iflags)) + if (buf->flushpending) break; count = head->commit - head->read; @@ -505,6 +505,7 @@ void tty_buffer_init(struct tty_port *port) buf->tail = &buf->sentinel; init_llist_head(&buf->free); atomic_set(&buf->memory_used, 0); + buf->flushpending = 0; INIT_WORK(&buf->work, flush_to_ldisc); } diff --git a/include/linux/tty.h b/include/linux/tty.h index b8e8adf..991575f 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -68,6 +68,7 @@ struct tty_bufhead { struct tty_buffer *head; /* Queue head */ struct work_struct work; struct mutex flush_mutex; + unsigned int flushpending:1; struct tty_buffer sentinel; struct llist_head free; /* Free queue head */ atomic_t memory_used; /* In-use buffers excluding free list */ @@ -212,8 +213,6 @@ struct tty_port { wait_queue_head_t close_wait; /* Close waiters */ wait_queue_head_t delta_msr_wait; /* Modem status change */ unsigned long flags; /* TTY flags ASY_*/ - unsigned long iflags; /* TTYP_ internal flags */ -#define TTYP_FLUSHPENDING 2 /* Queued buffer flush pending */ unsigned char console:1, /* port is a console */ low_latency:1; /* direct buffer flush */ struct mutex mutex; /* Locking */ -- 2.7.4