Commit 0f56bd2f authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman

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: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8c1fb49b
...@@ -189,11 +189,11 @@ void tty_buffer_flush(struct tty_struct *tty) ...@@ -189,11 +189,11 @@ void tty_buffer_flush(struct tty_struct *tty)
struct tty_port *port = tty->port; struct tty_port *port = tty->port;
struct tty_bufhead *buf = &port->buf; struct tty_bufhead *buf = &port->buf;
set_bit(TTYP_FLUSHPENDING, &port->iflags); buf->flushpending = 1;
mutex_lock(&buf->flush_mutex); mutex_lock(&buf->flush_mutex);
__tty_buffer_flush(port); __tty_buffer_flush(port);
clear_bit(TTYP_FLUSHPENDING, &port->iflags); buf->flushpending = 0;
mutex_unlock(&buf->flush_mutex); mutex_unlock(&buf->flush_mutex);
} }
...@@ -426,7 +426,7 @@ static void flush_to_ldisc(struct work_struct *work) ...@@ -426,7 +426,7 @@ static void flush_to_ldisc(struct work_struct *work)
int count; int count;
/* Ldisc or user is trying to flush the buffers. */ /* Ldisc or user is trying to flush the buffers. */
if (test_bit(TTYP_FLUSHPENDING, &port->iflags)) if (buf->flushpending)
break; break;
count = head->commit - head->read; count = head->commit - head->read;
...@@ -505,6 +505,7 @@ void tty_buffer_init(struct tty_port *port) ...@@ -505,6 +505,7 @@ void tty_buffer_init(struct tty_port *port)
buf->tail = &buf->sentinel; buf->tail = &buf->sentinel;
init_llist_head(&buf->free); init_llist_head(&buf->free);
atomic_set(&buf->memory_used, 0); atomic_set(&buf->memory_used, 0);
buf->flushpending = 0;
INIT_WORK(&buf->work, flush_to_ldisc); INIT_WORK(&buf->work, flush_to_ldisc);
} }
...@@ -68,6 +68,7 @@ struct tty_bufhead { ...@@ -68,6 +68,7 @@ struct tty_bufhead {
struct tty_buffer *head; /* Queue head */ struct tty_buffer *head; /* Queue head */
struct work_struct work; struct work_struct work;
struct mutex flush_mutex; struct mutex flush_mutex;
unsigned int flushpending:1;
struct tty_buffer sentinel; struct tty_buffer sentinel;
struct llist_head free; /* Free queue head */ struct llist_head free; /* Free queue head */
atomic_t memory_used; /* In-use buffers excluding free list */ atomic_t memory_used; /* In-use buffers excluding free list */
...@@ -212,8 +213,6 @@ struct tty_port { ...@@ -212,8 +213,6 @@ struct tty_port {
wait_queue_head_t close_wait; /* Close waiters */ wait_queue_head_t close_wait; /* Close waiters */
wait_queue_head_t delta_msr_wait; /* Modem status change */ wait_queue_head_t delta_msr_wait; /* Modem status change */
unsigned long flags; /* TTY flags ASY_*/ 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 */ unsigned char console:1, /* port is a console */
low_latency:1; /* direct buffer flush */ low_latency:1; /* direct buffer flush */
struct mutex mutex; /* Locking */ struct mutex mutex; /* Locking */
......
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