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authorPeter Hurley <peter@hurleysoftware.com>2013-06-15 09:36:13 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-23 16:47:09 -0700
commit0f56bd2f6a97d8b0eb5c8f9bc04b83a6c16d1d48 (patch)
tree70337a7fd95f71d5f39aa9d168c09be2ff3465a1
parent8c1fb49ba107c7db9441ef6ec0ab5830d112cc2a (diff)
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op-kernel-dev-0f56bd2f6a97d8b0eb5c8f9bc04b83a6c16d1d48.tar.gz
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.c7
-rw-r--r--include/linux/tty.h3
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 */
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