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

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
Linus Torvalds
2 parents d0c15ad760 7deb39ed8d
Showing 6 changed files Side-by-side Diff
drivers/tty/serial/8250/8250_core.c
drivers/tty/serial/8250/8250_dma.c
drivers/tty/serial/samsung.c
drivers/tty/serial/serial_core.c
drivers/tty/tty_buffer.c
include/linux/tty.h
@@ -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);
@@ -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;
+	unsigned long	flags;
  
-	dma->tx_running = 0;
-
 	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)
@@ -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);
+	unsigned int ufcon = rd_regl(port, S3C2410_UFCON);
  
-	/* not possible to xmit on unconfigured port */
-	if (!s3c24xx_port_configured(ucon))
-		return;
-
 	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);
 }
  
@@ -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;
 		}
@@ -1569,12 +1578,6 @@
 		retval = -EAGAIN;
 		goto err_dec_count;
 	}
-
-	/*
-	 * 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.
@@ -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;
@@ -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 */
...	...	@@ -1520,7 +1520,7 @@
1520	1520	status = serial8250_rx_chars(up, status);
1521	1521	}
1522	1522	serial8250_modem_status(up);
1523		- if (status & UART_LSR_THRE)
	1523	+ if (!up->dma && (status & UART_LSR_THRE))
1524	1524	serial8250_tx_chars(up);
1525	1525
1526	1526	spin_unlock_irqrestore(&port->lock, flags);
...	...	@@ -20,12 +20,15 @@
20	20	struct uart_8250_port *p = param;
21	21	struct uart_8250_dma *dma = p->dma;
22	22	struct circ_buf *xmit = &p->port.state->xmit;
	23	+ unsigned long flags;
23	24
24		- dma->tx_running = 0;
25		-
26	25	dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr,
27	26	UART_XMIT_SIZE, DMA_TO_DEVICE);
28	27
	28	+ spin_lock_irqsave(&p->port.lock, flags);
	29	+
	30	+ dma->tx_running = 0;
	31	+
29	32	xmit->tail += dma->tx_size;
30	33	xmit->tail &= UART_XMIT_SIZE - 1;
31	34	p->port.icount.tx += dma->tx_size;
...	...	@@ -35,6 +38,8 @@
35	38
36	39	if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port))
37	40	serial8250_tx_dma(p);
	41	+
	42	+ spin_unlock_irqrestore(&p->port.lock, flags);
38	43	}
39	44
40	45	static void __dma_rx_complete(void *param)
...	...	@@ -1446,8 +1446,8 @@
1446	1446	static void s3c24xx_serial_put_poll_char(struct uart_port *port,
1447	1447	unsigned char c)
1448	1448	{
1449		- unsigned int ufcon = rd_regl(cons_uart, S3C2410_UFCON);
1450		- unsigned int ucon = rd_regl(cons_uart, S3C2410_UCON);
	1449	+ unsigned int ufcon = rd_regl(port, S3C2410_UFCON);
	1450	+ unsigned int ucon = rd_regl(port, S3C2410_UCON);
1451	1451
1452	1452	/* not possible to xmit on unconfigured port */
1453	1453	if (!s3c24xx_port_configured(ucon))
...	...	@@ -1455,7 +1455,7 @@
1455	1455
1456	1456	while (!s3c24xx_serial_console_txrdy(port, ufcon))
1457	1457	cpu_relax();
1458		- wr_regb(cons_uart, S3C2410_UTXH, c);
	1458	+ wr_regb(port, S3C2410_UTXH, c);
1459	1459	}
1460	1460
1461	1461	#endif /* CONFIG_CONSOLE_POLL */
1462	1462
1463	1463
1464	1464
...	...	@@ -1463,22 +1463,23 @@
1463	1463	static void
1464	1464	s3c24xx_serial_console_putchar(struct uart_port *port, int ch)
1465	1465	{
1466		- unsigned int ufcon = rd_regl(cons_uart, S3C2410_UFCON);
1467		- unsigned int ucon = rd_regl(cons_uart, S3C2410_UCON);
	1466	+ unsigned int ufcon = rd_regl(port, S3C2410_UFCON);
1468	1467
1469		- /* not possible to xmit on unconfigured port */
1470		- if (!s3c24xx_port_configured(ucon))
1471		- return;
1472		-
1473	1468	while (!s3c24xx_serial_console_txrdy(port, ufcon))
1474		- barrier();
1475		- wr_regb(cons_uart, S3C2410_UTXH, ch);
	1469	+ cpu_relax();
	1470	+ wr_regb(port, S3C2410_UTXH, ch);
1476	1471	}
1477	1472
1478	1473	static void
1479	1474	s3c24xx_serial_console_write(struct console co, const char s,
1480	1475	unsigned int count)
1481	1476	{
	1477	+ unsigned int ucon = rd_regl(cons_uart, S3C2410_UCON);
	1478	+
	1479	+ /* not possible to xmit on unconfigured port */
	1480	+ if (!s3c24xx_port_configured(ucon))
	1481	+ return;
	1482	+
1482	1483	uart_console_write(cons_uart, s, count, s3c24xx_serial_console_putchar);
1483	1484	}
1484	1485
...	...	@@ -137,6 +137,11 @@
137	137	return 1;
138	138
139	139	/*
	140	+ * Make sure the device is in D0 state.
	141	+ */
	142	+ uart_change_pm(state, UART_PM_STATE_ON);
	143	+
	144	+ /*
140	145	* Initialise and allocate the transmit and temporary
141	146	* buffer.
142	147	*/
143	148
144	149
...	...	@@ -825,25 +830,29 @@
825	830	* If we fail to request resources for the
826	831	* new port, try to restore the old settings.
827	832	*/
828		- if (retval && old_type != PORT_UNKNOWN) {
	833	+ if (retval) {
829	834	uport->iobase = old_iobase;
830	835	uport->type = old_type;
831	836	uport->hub6 = old_hub6;
832	837	uport->iotype = old_iotype;
833	838	uport->regshift = old_shift;
834	839	uport->mapbase = old_mapbase;
835		- retval = uport->ops->request_port(uport);
836		- /*
837		- * If we failed to restore the old settings,
838		- * we fail like this.
839		- */
840		- if (retval)
841		- uport->type = PORT_UNKNOWN;
842	840
843		- /*
844		- * We failed anyway.
845		- */
846		- retval = -EBUSY;
	841	+ if (old_type != PORT_UNKNOWN) {
	842	+ retval = uport->ops->request_port(uport);
	843	+ /*
	844	+ * If we failed to restore the old settings,
	845	+ * we fail like this.
	846	+ */
	847	+ if (retval)
	848	+ uport->type = PORT_UNKNOWN;
	849	+
	850	+ /*
	851	+ * We failed anyway.
	852	+ */
	853	+ retval = -EBUSY;
	854	+ }
	855	+
847	856	/* Added to return the correct error -Ram Gupta */
848	857	goto exit;
849	858	}
...	...	@@ -1569,12 +1578,6 @@
1569	1578	retval = -EAGAIN;
1570	1579	goto err_dec_count;
1571	1580	}
1572		-
1573		- /*
1574		- * Make sure the device is in D0 state.
1575		- */
1576		- if (port->count == 1)
1577		- uart_change_pm(state, UART_PM_STATE_ON);
1578	1581
1579	1582	/*
1580	1583	* Start up the serial port.
...	...	@@ -255,11 +255,16 @@
255	255	if (change \|\| left < size) {
256	256	/* This is the slow path - looking for new buffers to use */
257	257	if ((n = tty_buffer_alloc(port, size)) != NULL) {
	258	+ unsigned long iflags;
	259	+
258	260	n->flags = flags;
259	261	buf->tail = n;
	262	+
	263	+ spin_lock_irqsave(&buf->flush_lock, iflags);
260	264	b->commit = b->used;
261		- smp_mb();
262	265	b->next = n;
	266	+ spin_unlock_irqrestore(&buf->flush_lock, iflags);
	267	+
263	268	} else if (change)
264	269	size = 0;
265	270	else
...	...	@@ -443,6 +448,7 @@
443	448	mutex_lock(&buf->lock);
444	449
445	450	while (1) {
	451	+ unsigned long flags;
446	452	struct tty_buffer *head = buf->head;
447	453	int count;
448	454
449	455
450	456
451	457
452	458
...	...	@@ -450,14 +456,19 @@
450	456	if (atomic_read(&buf->priority))
451	457	break;
452	458
	459	+ spin_lock_irqsave(&buf->flush_lock, flags);
453	460	count = head->commit - head->read;
454	461	if (!count) {
455		- if (head->next == NULL)
	462	+ if (head->next == NULL) {
	463	+ spin_unlock_irqrestore(&buf->flush_lock, flags);
456	464	break;
	465	+ }
457	466	buf->head = head->next;
	467	+ spin_unlock_irqrestore(&buf->flush_lock, flags);
458	468	tty_buffer_free(port, head);
459	469	continue;
460	470	}
	471	+ spin_unlock_irqrestore(&buf->flush_lock, flags);
461	472
462	473	count = receive_buf(tty, head, count);
463	474	if (!count)
...	...	@@ -512,6 +523,7 @@
512	523	struct tty_bufhead *buf = &port->buf;
513	524
514	525	mutex_init(&buf->lock);
	526	+ spin_lock_init(&buf->flush_lock);
515	527	tty_buffer_reset(&buf->sentinel, 0);
516	528	buf->head = &buf->sentinel;
517	529	buf->tail = &buf->sentinel;
...	...	@@ -61,6 +61,7 @@
61	61	struct tty_buffer head; / Queue head */
62	62	struct work_struct work;
63	63	struct mutex lock;
	64	+ spinlock_t flush_lock;
64	65	atomic_t priority;
65	66	struct tty_buffer sentinel;
66	67	struct llist_head free; /* Free queue head */