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spi: ar934x: Don't leak SPI master in probe error path 

If the call to devm_spi_register_controller() fails on probe of the
Qualcomm Atheros AR934x/QCA95xx SPI driver, the spi_controller struct is
erroneously not freed.  Fix by switching over to the new
devm_spi_alloc_master() helper.

Moreover, the controller's clock is enabled on probe but not disabled if
any of the subsequent probe steps fail.

Finally, there's an ordering issue in ar934x_spi_remove() wherein the
clock is disabled even though the controller is not yet unregistered.
It is unregistered after ar934x_spi_remove() by the devres framework.
As long as it is not unregistered, SPI transfers may still be ongoing
and disabling the clock may break them.  It is not possible to use
devm_spi_register_controller() in this case, so move to the non-devm
variant.

All of these bugs have existed since the driver was first introduced,
so it seems fair to fix them together in a single commit.

Fixes: 047980c582 ("spi: add driver for ar934x spi controller")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v5.7+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v5.7+
Cc: Chuanhong Guo <gch981213@gmail.com>
Link: https://lore.kernel.org/r/1d58367d74d55741e0c2730a51a2b65012c8ab33.1607286887.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Lukas Wunner 2020-12-07 09:17:15 +01:00 committed by Mark Brown
parent 46b5c4fb87
commit 236924ee53
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GPG Key ID: 24D68B725D5487D0
1 changed files with 11 additions and 3 deletions
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14
drivers/spi/spi-ar934x.c
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@ -176,10 +176,11 @@ static int ar934x_spi_probe(struct platform_device *pdev)
if (ret)
return ret;
ctlr = spi_alloc_master(&pdev->dev, sizeof(*sp));
ctlr = devm_spi_alloc_master(&pdev->dev, sizeof(*sp));
if (!ctlr) {
dev_info(&pdev->dev, "failed to allocate spi controller\n");
return -ENOMEM;
ret = -ENOMEM;
goto err_clk_disable;
}
/* disable flash mapping and expose spi controller registers */
@ -202,7 +203,13 @@ static int ar934x_spi_probe(struct platform_device *pdev)
sp->clk_freq = clk_get_rate(clk);
sp->ctlr = ctlr;
return devm_spi_register_controller(&pdev->dev, ctlr);
ret = spi_register_controller(ctlr);
if (!ret)
return 0;
err_clk_disable:
clk_disable_unprepare(clk);
return ret;
}
static int ar934x_spi_remove(struct platform_device *pdev)
@ -213,6 +220,7 @@ static int ar934x_spi_remove(struct platform_device *pdev)
ctlr = dev_get_drvdata(&pdev->dev);
sp = spi_controller_get_devdata(ctlr);
spi_unregister_controller(ctlr);
clk_disable_unprepare(sp->clk);
return 0;