diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2013-06-15 15:36:13 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-07-24 01:47:09 +0200 |
| commit | 0f56bd2f6a97d8b0eb5c8f9bc04b83a6c16d1d48 (patch) | |
| tree | 70337a7fd95f71d5f39aa9d168c09be2ff3465a1 | |
| parent | tty: Avoid false-sharing flip buffer ptrs (diff) | |
| download | linux-0f56bd2f6a97d8b0eb5c8f9bc04b83a6c16d1d48.tar.xz linux-0f56bd2f6a97d8b0eb5c8f9bc04b83a6c16d1d48.zip | |
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 <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/tty_buffer.c | 7 | ||||
| -rw-r--r-- | 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 39cae611fe59..fb042b9a8d68 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 b8e8adf95bf3..991575fe3451 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 */ |