[PATCH 00/52] serial: Convert to platform remove callback returning void

[PATCH 00/52] serial: Convert to platform remove callback returning void

[Uwe Kleine-König]

Hello,

this series starts with two fixes. The first one fixes a resource leak
and use after free. The second only improves error reporting. I added a
Fixes: marker to these. I let you decide if you want to drop them (or
the second only) or add a Cc: stable (to both or only the first one).

After that all drivers below drivers/tty/serial are converted to struct
platform_driver::remove_new. See commit 5c5a7680e67b ("platform: Provide
a remove callback that returns no value") for an extended explanation
and the eventual goal. The TL;DR; is to prevent bugs like the two fixed
here.

After these two fixes all conversations are trivial, because all
.remove() callbacks returned zero unconditionally.

The conversion patches are merge window material. The two fixes might go
in also before v6.7, but given the fixed problems are already old
(v6.1-rc6 + v3.10-rc1) there is probably no urge.

Best regards
Uwe

Uwe Kleine-König (52):
  serial: 8250: omap: Don't skip resource freeing if
    pm_runtime_resume_and_get() failed
  serial: sccnxp: Improve error message if regulator_disable() fails
  serial: 8250: Convert to platform remove callback returning void
  serial: altera_jtaguart: Convert to platform remove callback returning
    void
  serial: altera: Convert to platform remove callback returning void
  serial: amba-pl011: Convert to platform remove callback returning void
  serial: ar933x: Convert to platform remove callback returning void
  serial: atmel: Convert to platform remove callback returning void
  serial: bcm63xx: Convert to platform remove callback returning void
  serial: clps711x: Convert to platform remove callback returning void
  serial: cpm: Convert to platform remove callback returning void
  serial: digicolor: Convert to platform remove callback returning void
  serial: esp32_acm: Convert to platform remove callback returning void
  serial: esp32: Convert to platform remove callback returning void
  serial: fsl_linflexuart: Convert to platform remove callback returning
    void
  serial: fsl_lpuart: Convert to platform remove callback returning void
  serial: imx: Convert to platform remove callback returning void
  serial: lantiq: Convert to platform remove callback returning void
  serial: liteuart: Convert to platform remove callback returning void
  serial: lpc32xx_hs: Convert to platform remove callback returning void
  serial: ma35d1: Convert to platform remove callback returning void
  serial: mcf: Convert to platform remove callback returning void
  serial: meson: Convert to platform remove callback returning void
  serial: milbeaut_usio: Convert to platform remove callback returning
    void
  serial: mpc52xx: Convert to platform remove callback returning void
  serial: msm: Convert to platform remove callback returning void
  serial: mxs-auart: Convert to platform remove callback returning void
  serial: omap: Convert to platform remove callback returning void
  serial: owl: Convert to platform remove callback returning void
  serial: pic32: Convert to platform remove callback returning void
  serial: qcom_geni: Convert to platform remove callback returning void
  serial: rda: Convert to platform remove callback returning void
  serial: sa1100: Convert to platform remove callback returning void
  serial: samsung: Convert to platform remove callback returning void
  serial: sccnxp: Convert to platform remove callback returning void
  serial: tegra: Convert to platform remove callback returning void
  serial: txx9: Convert to platform remove callback returning void
  serial: sh-sci: Convert to platform remove callback returning void
  serial: sifive: Convert to platform remove callback returning void
  serial: sprd: Convert to platform remove callback returning void
  serial: st-asc: Convert to platform remove callback returning void
  serial: stm32: Convert to platform remove callback returning void
  serial: sunhv: Convert to platform remove callback returning void
  serial: sunplus: Convert to platform remove callback returning void
  serial: sunsab: Convert to platform remove callback returning void
  serial: sunsu: Convert to platform remove callback returning void
  serial: sunzilog: Convert to platform remove callback returning void
  serial: tegra-tcu: Convert to platform remove callback returning void
  serial: timbuart: Convert to platform remove callback returning void
  serial: uartlite: Convert to platform remove callback returning void
  serial: ucc: Convert to platform remove callback returning void
  serial: xilinx_uartps: Convert to platform remove callback returning
    void

 drivers/tty/serial/8250/8250_aspeed_vuart.c |  6 ++----
 drivers/tty/serial/8250/8250_bcm2835aux.c   |  6 ++----
 drivers/tty/serial/8250/8250_bcm7271.c      |  5 ++---
 drivers/tty/serial/8250/8250_core.c         |  5 ++---
 drivers/tty/serial/8250/8250_dw.c           |  6 ++----
 drivers/tty/serial/8250/8250_em.c           |  5 ++---
 drivers/tty/serial/8250/8250_fsl.c          |  5 ++---
 drivers/tty/serial/8250/8250_ingenic.c      |  5 ++---
 drivers/tty/serial/8250/8250_ioc3.c         |  5 ++---
 drivers/tty/serial/8250/8250_lpc18xx.c      |  6 ++----
 drivers/tty/serial/8250/8250_mtk.c          |  6 ++----
 drivers/tty/serial/8250/8250_of.c           |  5 ++---
 drivers/tty/serial/8250/8250_omap.c         |  7 +++----
 drivers/tty/serial/8250/8250_pxa.c          |  6 ++----
 drivers/tty/serial/8250/8250_tegra.c        |  6 ++----
 drivers/tty/serial/8250/8250_uniphier.c     |  6 ++----
 drivers/tty/serial/altera_jtaguart.c        |  6 ++----
 drivers/tty/serial/altera_uart.c            |  6 ++----
 drivers/tty/serial/amba-pl011.c             |  5 ++---
 drivers/tty/serial/ar933x_uart.c            |  6 ++----
 drivers/tty/serial/atmel_serial.c           |  6 ++----
 drivers/tty/serial/bcm63xx_uart.c           |  5 ++---
 drivers/tty/serial/clps711x.c               |  6 ++----
 drivers/tty/serial/cpm_uart.c               |  6 ++----
 drivers/tty/serial/digicolor-usart.c        |  6 ++----
 drivers/tty/serial/esp32_acm.c              |  5 ++---
 drivers/tty/serial/esp32_uart.c             |  6 ++----
 drivers/tty/serial/fsl_linflexuart.c        |  6 ++----
 drivers/tty/serial/fsl_lpuart.c             |  5 ++---
 drivers/tty/serial/imx.c                    |  6 ++----
 drivers/tty/serial/lantiq.c                 |  6 ++----
 drivers/tty/serial/liteuart.c               |  6 ++----
 drivers/tty/serial/lpc32xx_hs.c             |  6 ++----
 drivers/tty/serial/ma35d1_serial.c          |  5 ++---
 drivers/tty/serial/mcf.c                    |  6 ++----
 drivers/tty/serial/meson_uart.c             |  8 +++-----
 drivers/tty/serial/milbeaut_usio.c          |  6 ++----
 drivers/tty/serial/mpc52xx_uart.c           |  7 ++-----
 drivers/tty/serial/msm_serial.c             |  6 ++----
 drivers/tty/serial/mxs-auart.c              |  6 ++----
 drivers/tty/serial/omap-serial.c            |  6 ++----
 drivers/tty/serial/owl-uart.c               |  6 ++----
 drivers/tty/serial/pic32_uart.c             |  7 ++-----
 drivers/tty/serial/qcom_geni_serial.c       |  6 ++----
 drivers/tty/serial/rda-uart.c               |  6 ++----
 drivers/tty/serial/sa1100.c                 |  6 ++----
 drivers/tty/serial/samsung_tty.c            |  6 ++----
 drivers/tty/serial/sccnxp.c                 | 13 +++++++------
 drivers/tty/serial/serial-tegra.c           |  5 ++---
 drivers/tty/serial/serial_txx9.c            |  5 ++---
 drivers/tty/serial/sh-sci.c                 |  6 ++----
 drivers/tty/serial/sifive.c                 |  6 ++----
 drivers/tty/serial/sprd_serial.c            |  6 ++----
 drivers/tty/serial/st-asc.c                 |  6 ++----
 drivers/tty/serial/stm32-usart.c            |  6 ++----
 drivers/tty/serial/sunhv.c                  |  6 ++----
 drivers/tty/serial/sunplus-uart.c           |  6 ++----
 drivers/tty/serial/sunsab.c                 |  6 ++----
 drivers/tty/serial/sunsu.c                  |  6 ++----
 drivers/tty/serial/sunzilog.c               |  6 ++----
 drivers/tty/serial/tegra-tcu.c              |  6 ++----
 drivers/tty/serial/timbuart.c               |  6 ++----
 drivers/tty/serial/uartlite.c               |  5 ++---
 drivers/tty/serial/ucc_uart.c               |  6 ++----
 drivers/tty/serial/xilinx_uartps.c          |  5 ++---
 65 files changed, 137 insertions(+), 249 deletions(-)


base-commit: 8728c14129df7a6e29188a2e737b4774fb200953
-- 
2.42.0

[PATCH 34/52] serial: samsung: Convert to platform remove callback returning void

[Uwe Kleine-König]

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/tty/serial/samsung_tty.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 3bd552841cd2..1b0c2b467a30 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -2054,7 +2054,7 @@ static int s3c24xx_serial_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static int s3c24xx_serial_remove(struct platform_device *dev)
+static void s3c24xx_serial_remove(struct platform_device *dev)
 {
 	struct uart_port *port = s3c24xx_dev_to_port(&dev->dev);
 
@@ -2063,8 +2063,6 @@ static int s3c24xx_serial_remove(struct platform_device *dev)
 	}
 
 	uart_unregister_driver(&s3c24xx_uart_drv);
-
-	return 0;
 }
 
 /* UART power management code */
@@ -2611,7 +2609,7 @@ MODULE_DEVICE_TABLE(of, s3c24xx_uart_dt_match);
 
 static struct platform_driver samsung_serial_driver = {
 	.probe		= s3c24xx_serial_probe,
-	.remove		= s3c24xx_serial_remove,
+	.remove_new	= s3c24xx_serial_remove,
 	.id_table	= s3c24xx_serial_driver_ids,
 	.driver		= {
 		.name	= "samsung-uart",
-- 
2.42.0

Re: [PATCH 34/52] serial: samsung: Convert to platform remove callback returning void

[Krzysztof Kozlowski]

On 10/11/2023 16:30, Uwe Kleine-König wrote:
> The .remove() callback for a platform driver returns an int which makes
> many driver authors wrongly assume it's possible to do error handling by
> returning an error code. However the value returned is ignored (apart
> from emitting a warning) and this typically results in resource leaks.
> 
> To improve here there is a quest to make the remove callback return
> void. In the first step of this quest all drivers are converted to
> .remove_new(), which already returns void. Eventually after all drivers
> are converted, .remove_new() will be renamed to .remove().
> 
> Trivially convert this driver from always returning zero in the remove
> callback to the void returning variant.

Maybe let's trim the commit msg? Or convert all drivers at once if you
want to drop long explanation...

> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---


Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [PATCH 34/52] serial: samsung: Convert to platform remove callback returning void

[Uwe Kleine-König]

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On Sun, Nov 12, 2023 at 08:48:49AM +0100, Krzysztof Kozlowski wrote:
> On 10/11/2023 16:30, Uwe Kleine-König wrote:
> > The .remove() callback for a platform driver returns an int which makes
> > many driver authors wrongly assume it's possible to do error handling by
> > returning an error code. However the value returned is ignored (apart
> > from emitting a warning) and this typically results in resource leaks.
> > 
> > To improve here there is a quest to make the remove callback return
> > void. In the first step of this quest all drivers are converted to
> > .remove_new(), which already returns void. Eventually after all drivers
> > are converted, .remove_new() will be renamed to .remove().
> > 
> > Trivially convert this driver from always returning zero in the remove
> > callback to the void returning variant.
> 
> Maybe let's trim the commit msg? Or convert all drivers at once if you
> want to drop long explanation...

I like the verbosity of the commit log. This way you have a chance to
understand its motivation by only looking at that single commit.

IMHO doing one commit per driver is also right: It simplifies review,
allows me to send patches to only the respective maintainers and so
annoy less, the people reviewing the changes can send a tag for the
driver change they look at only.

But I'm not religious about that and if Greg wants to squash the patches
together that's ok for me.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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