Merge tag 'tty-3.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial fixes from Greg KH:
"Here are a few tty/serial fixes for 3.15-rc3 that resolve a number of
reported issues in the 8250 and samsung serial drivers, as well as a
character loss fix for the tty core that was caused by the lock
removal patches a release ago"
* tag 'tty-3.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
serial_core: fix uart PORT_UNKNOWN handling
serial: samsung: Change barrier() to cpu_relax() in console output
serial: samsung: don't check config for every character
serial: samsung: Use the passed in "port", fixing kgdb w/ no console
serial: 8250: Fix thread unsafe __dma_tx_complete function
8250_core: Fix unwanted TX chars write
tty: Fix race condition between __tty_buffer_request_room and flush_to_ldisc
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 81f909c..0e1bf88 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1520,7 +1520,7 @@
status = serial8250_rx_chars(up, status);
}
serial8250_modem_status(up);
- if (status & UART_LSR_THRE)
+ if (!up->dma && (status & UART_LSR_THRE))
serial8250_tx_chars(up);
spin_unlock_irqrestore(&port->lock, flags);
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index 7046769..ab9096d 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -20,12 +20,15 @@
struct uart_8250_port *p = param;
struct uart_8250_dma *dma = p->dma;
struct circ_buf *xmit = &p->port.state->xmit;
-
- dma->tx_running = 0;
+ unsigned long flags;
dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr,
UART_XMIT_SIZE, DMA_TO_DEVICE);
+ spin_lock_irqsave(&p->port.lock, flags);
+
+ dma->tx_running = 0;
+
xmit->tail += dma->tx_size;
xmit->tail &= UART_XMIT_SIZE - 1;
p->port.icount.tx += dma->tx_size;
@@ -35,6 +38,8 @@
if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port))
serial8250_tx_dma(p);
+
+ spin_unlock_irqrestore(&p->port.lock, flags);
}
static void __dma_rx_complete(void *param)
diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index 23f4596..1f5505e 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -1446,8 +1446,8 @@
static void s3c24xx_serial_put_poll_char(struct uart_port *port,
unsigned char c)
{
- unsigned int ufcon = rd_regl(cons_uart, S3C2410_UFCON);
- unsigned int ucon = rd_regl(cons_uart, S3C2410_UCON);
+ unsigned int ufcon = rd_regl(port, S3C2410_UFCON);
+ unsigned int ucon = rd_regl(port, S3C2410_UCON);
/* not possible to xmit on unconfigured port */
if (!s3c24xx_port_configured(ucon))
@@ -1455,7 +1455,7 @@
while (!s3c24xx_serial_console_txrdy(port, ufcon))
cpu_relax();
- wr_regb(cons_uart, S3C2410_UTXH, c);
+ wr_regb(port, S3C2410_UTXH, c);
}
#endif /* CONFIG_CONSOLE_POLL */
@@ -1463,22 +1463,23 @@
static void
s3c24xx_serial_console_putchar(struct uart_port *port, int ch)
{
- unsigned int ufcon = rd_regl(cons_uart, S3C2410_UFCON);
- unsigned int ucon = rd_regl(cons_uart, S3C2410_UCON);
-
- /* not possible to xmit on unconfigured port */
- if (!s3c24xx_port_configured(ucon))
- return;
+ unsigned int ufcon = rd_regl(port, S3C2410_UFCON);
while (!s3c24xx_serial_console_txrdy(port, ufcon))
- barrier();
- wr_regb(cons_uart, S3C2410_UTXH, ch);
+ cpu_relax();
+ wr_regb(port, S3C2410_UTXH, ch);
}
static void
s3c24xx_serial_console_write(struct console *co, const char *s,
unsigned int count)
{
+ unsigned int ucon = rd_regl(cons_uart, S3C2410_UCON);
+
+ /* not possible to xmit on unconfigured port */
+ if (!s3c24xx_port_configured(ucon))
+ return;
+
uart_console_write(cons_uart, s, count, s3c24xx_serial_console_putchar);
}
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index f26834d..b68550d 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -137,6 +137,11 @@
return 1;
/*
+ * Make sure the device is in D0 state.
+ */
+ uart_change_pm(state, UART_PM_STATE_ON);
+
+ /*
* Initialise and allocate the transmit and temporary
* buffer.
*/
@@ -825,25 +830,29 @@
* If we fail to request resources for the
* new port, try to restore the old settings.
*/
- if (retval && old_type != PORT_UNKNOWN) {
+ if (retval) {
uport->iobase = old_iobase;
uport->type = old_type;
uport->hub6 = old_hub6;
uport->iotype = old_iotype;
uport->regshift = old_shift;
uport->mapbase = old_mapbase;
- retval = uport->ops->request_port(uport);
- /*
- * If we failed to restore the old settings,
- * we fail like this.
- */
- if (retval)
- uport->type = PORT_UNKNOWN;
- /*
- * We failed anyway.
- */
- retval = -EBUSY;
+ if (old_type != PORT_UNKNOWN) {
+ retval = uport->ops->request_port(uport);
+ /*
+ * If we failed to restore the old settings,
+ * we fail like this.
+ */
+ if (retval)
+ uport->type = PORT_UNKNOWN;
+
+ /*
+ * We failed anyway.
+ */
+ retval = -EBUSY;
+ }
+
/* Added to return the correct error -Ram Gupta */
goto exit;
}
@@ -1571,12 +1580,6 @@
}
/*
- * Make sure the device is in D0 state.
- */
- if (port->count == 1)
- uart_change_pm(state, UART_PM_STATE_ON);
-
- /*
* Start up the serial port.
*/
retval = uart_startup(tty, state, 0);
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 8ebd9f8..f1d30f6 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -255,11 +255,16 @@
if (change || left < size) {
/* This is the slow path - looking for new buffers to use */
if ((n = tty_buffer_alloc(port, size)) != NULL) {
+ unsigned long iflags;
+
n->flags = flags;
buf->tail = n;
+
+ spin_lock_irqsave(&buf->flush_lock, iflags);
b->commit = b->used;
- smp_mb();
b->next = n;
+ spin_unlock_irqrestore(&buf->flush_lock, iflags);
+
} else if (change)
size = 0;
else
@@ -443,6 +448,7 @@
mutex_lock(&buf->lock);
while (1) {
+ unsigned long flags;
struct tty_buffer *head = buf->head;
int count;
@@ -450,14 +456,19 @@
if (atomic_read(&buf->priority))
break;
+ spin_lock_irqsave(&buf->flush_lock, flags);
count = head->commit - head->read;
if (!count) {
- if (head->next == NULL)
+ if (head->next == NULL) {
+ spin_unlock_irqrestore(&buf->flush_lock, flags);
break;
+ }
buf->head = head->next;
+ spin_unlock_irqrestore(&buf->flush_lock, flags);
tty_buffer_free(port, head);
continue;
}
+ spin_unlock_irqrestore(&buf->flush_lock, flags);
count = receive_buf(tty, head, count);
if (!count)
@@ -512,6 +523,7 @@
struct tty_bufhead *buf = &port->buf;
mutex_init(&buf->lock);
+ spin_lock_init(&buf->flush_lock);
tty_buffer_reset(&buf->sentinel, 0);
buf->head = &buf->sentinel;
buf->tail = &buf->sentinel;
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 1c3316a..036cccd 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -61,6 +61,7 @@
struct tty_buffer *head; /* Queue head */
struct work_struct work;
struct mutex lock;
+ spinlock_t flush_lock;
atomic_t priority;
struct tty_buffer sentinel;
struct llist_head free; /* Free queue head */
