linux-kernel - [PATCH 2/7] tty: serial: fsl_lpuart: free IDs allocated by IDA

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Date:   Thu, 20 Feb 2020 18:43:29 +0100
From:   Michael Walle <michael@...le.cc>
To:     linux-serial@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Shawn Guo <shawnguo@...nel.org>, Li Yang <leoyang.li@....com>,
        Jiri Slaby <jslaby@...e.com>, Peng Fan <peng.fan@....com>,
        Yuan Yao <yao.yuan@....com>,
        Vabhav Sharma <vabhav.sharma@....com>,
        Michael Walle <michael@...le.cc>
Subject: [PATCH 2/7] tty: serial: fsl_lpuart: free IDs allocated by IDA

Since commit 3bc3206e1c0f ("serial: fsl_lpuart: Remove the alias node
dependence") the port line number can also be allocated by IDA, but in
case of an error the ID will no be removed again. More importantly, any
ID will be freed in remove(), even if it wasn't allocated but instead
fetched by of_alias_get_id(). If it was not allocated by IDA there will
be a warning:
  WARN(1, "ida_free called for id=%d which is not allocated.\n", id);

Move the ID allocation more to the end of the probe() so that we still
can use plain return in the first error cases.

Fixes: 3bc3206e1c0f ("serial: fsl_lpuart: Remove the alias node dependence")
Signed-off-by: Michael Walle <michael@...le.cc>
---
 drivers/tty/serial/fsl_lpuart.c | 39 ++++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 27fdc131c352..c31b8f3db6bf 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -264,6 +264,7 @@ struct lpuart_port {
 	int			rx_dma_rng_buf_len;
 	unsigned int		dma_tx_nents;
 	wait_queue_head_t	dma_wait;
+	bool			id_allocated;
 };
 
 struct lpuart_soc_data {
@@ -2422,19 +2423,6 @@ static int lpuart_probe(struct platform_device *pdev)
 	if (!sport)
 		return -ENOMEM;
 
-	ret = of_alias_get_id(np, "serial");
-	if (ret < 0) {
-		ret = ida_simple_get(&fsl_lpuart_ida, 0, UART_NR, GFP_KERNEL);
-		if (ret < 0) {
-			dev_err(&pdev->dev, "port line is full, add device failed\n");
-			return ret;
-		}
-	}
-	if (ret >= ARRAY_SIZE(lpuart_ports)) {
-		dev_err(&pdev->dev, "serial%d out of range\n", ret);
-		return -EINVAL;
-	}
-	sport->port.line = ret;
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	sport->port.membase = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(sport->port.membase))
@@ -2479,9 +2467,25 @@ static int lpuart_probe(struct platform_device *pdev)
 		}
 	}
 
+	ret = of_alias_get_id(np, "serial");
+	if (ret < 0) {
+		ret = ida_simple_get(&fsl_lpuart_ida, 0, UART_NR, GFP_KERNEL);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "port line is full, add device failed\n");
+			return ret;
+		}
+		sport->id_allocated = true;
+	}
+	if (ret >= ARRAY_SIZE(lpuart_ports)) {
+		dev_err(&pdev->dev, "serial%d out of range\n", ret);
+		ret = -EINVAL;
+		goto failed_out_of_range;
+	}
+	sport->port.line = ret;
+
 	ret = lpuart_enable_clks(sport);
 	if (ret)
-		return ret;
+		goto failed_clock_enable;
 	sport->port.uartclk = lpuart_get_baud_clk_rate(sport);
 
 	lpuart_ports[sport->port.line] = sport;
@@ -2531,6 +2535,10 @@ static int lpuart_probe(struct platform_device *pdev)
 failed_attach_port:
 failed_irq_request:
 	lpuart_disable_clks(sport);
+failed_clock_enable:
+failed_out_of_range:
+	if (sport->id_allocated)
+		ida_simple_remove(&fsl_lpuart_ida, sport->port.line);
 	return ret;
 }
 
@@ -2540,7 +2548,8 @@ static int lpuart_remove(struct platform_device *pdev)
 
 	uart_remove_one_port(&lpuart_reg, &sport->port);
 
-	ida_simple_remove(&fsl_lpuart_ida, sport->port.line);
+	if (sport->id_allocated)
+		ida_simple_remove(&fsl_lpuart_ida, sport->port.line);
 
 	lpuart_disable_clks(sport);
 
-- 
2.20.1