[PATCH 00/13] fpga: Convert to platform remove callback returning void

[PATCH 00/13] fpga: Convert to platform remove callback returning void

[Uwe Kleine-König]

Hello,

this series converts all drivers below drivers/fpga to use
.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 make it harder for driver authors to
leak resources without noticing.

This is merge window material. All patches are pairwise independent of
each other, so they could be applied individually. Getting them all in
together would be nicer though :-)

Best regards
Uwe

Uwe Kleine-König (13):
  fpga: altera-fpga2sdram: Convert to platform remove callback returning void
  fpga: altera-freeze-bridge: Convert to platform remove callback returning void
  fpga: altera-hps2fpga: Convert to platform remove callback returning void
  fpga: dfl-afu-main: Convert to platform remove callback returning void
  fpga: dfl-fme-br: Convert to platform remove callback returning void
  fpga: dfl-fme-main: Convert to platform remove callback returning void
  fpga: dfl-fme-region: Convert to platform remove callback returning void
  fpga: intel-m10-bmc-sec-update: Convert to platform remove callback returning void
  fpga: of-fpga-region: Convert to platform remove callback returning void
  fpga: socfpga-a10: Convert to platform remove callback returning void
  fpga: stratix10-soc: Convert to platform remove callback returning void
  fpga: xilinx-pr-decoupler: Convert to platform remove callback returning void
  fpga: zynq-fpga: Convert to platform remove callback returning void

 drivers/fpga/altera-fpga2sdram.c        | 6 ++----
 drivers/fpga/altera-freeze-bridge.c     | 6 ++----
 drivers/fpga/altera-hps2fpga.c          | 6 ++----
 drivers/fpga/dfl-afu-main.c             | 6 ++----
 drivers/fpga/dfl-fme-br.c               | 6 ++----
 drivers/fpga/dfl-fme-main.c             | 6 ++----
 drivers/fpga/dfl-fme-region.c           | 6 ++----
 drivers/fpga/intel-m10-bmc-sec-update.c | 6 ++----
 drivers/fpga/of-fpga-region.c           | 6 ++----
 drivers/fpga/socfpga-a10.c              | 6 ++----
 drivers/fpga/stratix10-soc.c            | 6 ++----
 drivers/fpga/xilinx-pr-decoupler.c      | 6 ++----
 drivers/fpga/zynq-fpga.c                | 6 ++----
 13 files changed, 26 insertions(+), 52 deletions(-)

base-commit: aa4db8324c4d0e67aa4670356df4e9fae14b4d37
-- 
2.42.0


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[PATCH 12/13] fpga: xilinx-pr-decoupler: 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/fpga/xilinx-pr-decoupler.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/fpga/xilinx-pr-decoupler.c b/drivers/fpga/xilinx-pr-decoupler.c
index 68835896f180..788dd2f63a65 100644
--- a/drivers/fpga/xilinx-pr-decoupler.c
+++ b/drivers/fpga/xilinx-pr-decoupler.c
@@ -150,7 +150,7 @@ static int xlnx_pr_decoupler_probe(struct platform_device *pdev)
 	return err;
 }
 
-static int xlnx_pr_decoupler_remove(struct platform_device *pdev)
+static void xlnx_pr_decoupler_remove(struct platform_device *pdev)
 {
 	struct fpga_bridge *bridge = platform_get_drvdata(pdev);
 	struct xlnx_pr_decoupler_data *p = bridge->priv;
@@ -158,13 +158,11 @@ static int xlnx_pr_decoupler_remove(struct platform_device *pdev)
 	fpga_bridge_unregister(bridge);
 
 	clk_unprepare(p->clk);
-
-	return 0;
 }
 
 static struct platform_driver xlnx_pr_decoupler_driver = {
 	.probe = xlnx_pr_decoupler_probe,
-	.remove = xlnx_pr_decoupler_remove,
+	.remove_new = xlnx_pr_decoupler_remove,
 	.driver = {
 		.name = "xlnx_pr_decoupler",
 		.of_match_table = xlnx_pr_decoupler_of_match,
-- 
2.42.0


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[PATCH 13/13] fpga: zynq-fpga: 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/fpga/zynq-fpga.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/fpga/zynq-fpga.c b/drivers/fpga/zynq-fpga.c
index 96611d424a10..0ac93183d201 100644
--- a/drivers/fpga/zynq-fpga.c
+++ b/drivers/fpga/zynq-fpga.c
@@ -618,7 +618,7 @@ static int zynq_fpga_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static int zynq_fpga_remove(struct platform_device *pdev)
+static void zynq_fpga_remove(struct platform_device *pdev)
 {
 	struct zynq_fpga_priv *priv;
 	struct fpga_manager *mgr;
@@ -629,8 +629,6 @@ static int zynq_fpga_remove(struct platform_device *pdev)
 	fpga_mgr_unregister(mgr);
 
 	clk_unprepare(priv->clk);
-
-	return 0;
 }
 
 #ifdef CONFIG_OF
@@ -644,7 +642,7 @@ MODULE_DEVICE_TABLE(of, zynq_fpga_of_match);
 
 static struct platform_driver zynq_fpga_driver = {
 	.probe = zynq_fpga_probe,
-	.remove = zynq_fpga_remove,
+	.remove_new = zynq_fpga_remove,
 	.driver = {
 		.name = "zynq_fpga_manager",
 		.of_match_table = of_match_ptr(zynq_fpga_of_match),
-- 
2.42.0


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Re: [PATCH 00/13] fpga: Convert to platform remove callback returning void

[Xu Yilun]

On Tue, Dec 19, 2023 at 06:31:58PM +0100, Uwe Kleine-König wrote:
> Hello,
> 
> this series converts all drivers below drivers/fpga to use
> .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 make it harder for driver authors to
> leak resources without noticing.
> 
> This is merge window material. All patches are pairwise independent of
> each other, so they could be applied individually. Getting them all in
> together would be nicer though :-)
> 
> Best regards
> Uwe
> 
> Uwe Kleine-König (13):
>   fpga: altera-fpga2sdram: Convert to platform remove callback returning void
>   fpga: altera-freeze-bridge: Convert to platform remove callback returning void
>   fpga: altera-hps2fpga: Convert to platform remove callback returning void
>   fpga: dfl-afu-main: Convert to platform remove callback returning void
>   fpga: dfl-fme-br: Convert to platform remove callback returning void
>   fpga: dfl-fme-main: Convert to platform remove callback returning void
>   fpga: dfl-fme-region: Convert to platform remove callback returning void
>   fpga: intel-m10-bmc-sec-update: Convert to platform remove callback returning void
>   fpga: of-fpga-region: Convert to platform remove callback returning void
>   fpga: socfpga-a10: Convert to platform remove callback returning void
>   fpga: stratix10-soc: Convert to platform remove callback returning void
>   fpga: xilinx-pr-decoupler: Convert to platform remove callback returning void
>   fpga: zynq-fpga: Convert to platform remove callback returning void
> 
>  drivers/fpga/altera-fpga2sdram.c        | 6 ++----
>  drivers/fpga/altera-freeze-bridge.c     | 6 ++----
>  drivers/fpga/altera-hps2fpga.c          | 6 ++----
>  drivers/fpga/dfl-afu-main.c             | 6 ++----
>  drivers/fpga/dfl-fme-br.c               | 6 ++----
>  drivers/fpga/dfl-fme-main.c             | 6 ++----
>  drivers/fpga/dfl-fme-region.c           | 6 ++----
>  drivers/fpga/intel-m10-bmc-sec-update.c | 6 ++----
>  drivers/fpga/of-fpga-region.c           | 6 ++----
>  drivers/fpga/socfpga-a10.c              | 6 ++----
>  drivers/fpga/stratix10-soc.c            | 6 ++----
>  drivers/fpga/xilinx-pr-decoupler.c      | 6 ++----
>  drivers/fpga/zynq-fpga.c                | 6 ++----
>  13 files changed, 26 insertions(+), 52 deletions(-)

Acked-by: Xu Yilun <yilun.xu@intel.com>

And applied this series to for-next for 6.8-rc1.

> 
> base-commit: aa4db8324c4d0e67aa4670356df4e9fae14b4d37
> -- 
> 2.42.0
> 
> 

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