[PATCH] spi: fsl-dspi: use devm_spi_alloc_master()

From: Michael Walle
Date: Wed Nov 10 2021 - 11:18:04 EST


Commit 530b5affc675 ("spi: fsl-dspi: fix use-after-free in remove path")
fixed the use-after-free by manually allocating memory. Nowadays, since
commit 5e844cc37a5c ("spi: Introduce device-managed SPI controller
allocation"), there is a devres version of spi_alloc_master() for exactly
this purpose. Revert the commit which introduced the manual allocation
and use the new devm_spi_alloc_master().

Signed-off-by: Michael Walle <michael@xxxxxxxx>
---
Btw, using the devm_ version of spi_controller_register() doesn't seem to
be a good idea, see commit 8d559a64f00b ("spi: stm32: drop devres version
of spi_register_master").

drivers/spi/spi-fsl-dspi.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index fd004c9db9dc..29f8a596c8ee 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -1227,17 +1227,11 @@ static int dspi_probe(struct platform_device *pdev)
void __iomem *base;
bool big_endian;

- dspi = devm_kzalloc(&pdev->dev, sizeof(*dspi), GFP_KERNEL);
- if (!dspi)
- return -ENOMEM;
-
- ctlr = spi_alloc_master(&pdev->dev, 0);
+ ctlr = devm_spi_alloc_master(&pdev->dev, sizeof(struct fsl_dspi));
if (!ctlr)
return -ENOMEM;

- spi_controller_set_devdata(ctlr, dspi);
- platform_set_drvdata(pdev, dspi);
-
+ dspi = spi_controller_get_devdata(ctlr);
dspi->pdev = pdev;
dspi->ctlr = ctlr;

@@ -1373,6 +1367,8 @@ static int dspi_probe(struct platform_device *pdev)
if (dspi->devtype_data->trans_mode != DSPI_DMA_MODE)
ctlr->ptp_sts_supported = true;

+ platform_set_drvdata(pdev, ctlr);
+
ret = spi_register_controller(ctlr);
if (ret != 0) {
dev_err(&pdev->dev, "Problem registering DSPI ctlr\n");
@@ -1396,7 +1392,8 @@ static int dspi_probe(struct platform_device *pdev)

static int dspi_remove(struct platform_device *pdev)
{
- struct fsl_dspi *dspi = platform_get_drvdata(pdev);
+ struct spi_controller *ctlr = platform_get_drvdata(pdev);
+ struct fsl_dspi *dspi = spi_controller_get_devdata(ctlr);

/* Disconnect from the SPI framework */
spi_unregister_controller(dspi->ctlr);
--
2.30.2