[ Upstream commit 5e844cc37a5cbaa460e68f9a989d321d63088a89 ]
SPI driver probing currently comprises two steps, whereas removal comprises only one step:
spi_alloc_master() spi_register_master()
spi_unregister_master()
That's because spi_unregister_master() calls device_unregister() instead of device_del(), thereby releasing the reference on the spi_master which was obtained by spi_alloc_master().
An SPI driver's private data is contained in the same memory allocation as the spi_master struct. Thus, once spi_unregister_master() has been called, the private data is inaccessible. But some drivers need to access it after spi_unregister_master() to perform further teardown steps.
Introduce devm_spi_alloc_master(), which releases a reference on the spi_master struct only after the driver has unbound, thereby keeping the memory allocation accessible. Change spi_unregister_master() to not release a reference if the spi_master was allocated by the new devm function.
The present commit is small enough to be backportable to stable. It allows fixing drivers which use the private data in their ->remove() hook after it's been freed. It also allows fixing drivers which neglect to release a reference on the spi_master in the probe error path.
Long-term, most SPI drivers shall be moved over to the devm function introduced herein. The few that can't shall be changed in a treewide commit to explicitly release the last reference on the master. That commit shall amend spi_unregister_master() to no longer release a reference, thereby completing the migration.
As a result, the behaviour will be less surprising and more consistent with subsystems such as IIO, which also includes the private data in the allocation of the generic iio_dev struct, but calls device_del() in iio_device_unregister().
Signed-off-by: Lukas Wunner lukas@wunner.de Link: https://lore.kernel.org/r/272bae2ef08abd21388c98e23729886663d19192.160512103... Signed-off-by: Mark Brown broonie@kernel.org --- drivers/spi/spi.c | 54 ++++++++++++++++++++++++++++++++++++++++- include/linux/spi/spi.h | 2 ++ 2 files changed, 55 insertions(+), 1 deletion(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 6ed2959ce4dc..ed87f71a428d 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1720,6 +1720,46 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size) } EXPORT_SYMBOL_GPL(spi_alloc_master);
+static void devm_spi_release_master(struct device *dev, void *master) +{ + spi_master_put(*(struct spi_master **)master); +} + +/** + * devm_spi_alloc_master - resource-managed spi_alloc_master() + * @dev: physical device of SPI master + * @size: how much zeroed driver-private data to allocate + * Context: can sleep + * + * Allocate an SPI master and automatically release a reference on it + * when @dev is unbound from its driver. Drivers are thus relieved from + * having to call spi_master_put(). + * + * The arguments to this function are identical to spi_alloc_master(). + * + * Return: the SPI master structure on success, else NULL. + */ +struct spi_master *devm_spi_alloc_master(struct device *dev, unsigned int size) +{ + struct spi_master **ptr, *master; + + ptr = devres_alloc(devm_spi_release_master, sizeof(*ptr), + GFP_KERNEL); + if (!ptr) + return NULL; + + master = spi_alloc_master(dev, size); + if (master) { + *ptr = master; + devres_add(dev, ptr); + } else { + devres_free(ptr); + } + + return master; +} +EXPORT_SYMBOL_GPL(devm_spi_alloc_master); + #ifdef CONFIG_OF static int of_spi_register_master(struct spi_master *master) { @@ -1899,6 +1939,11 @@ int devm_spi_register_master(struct device *dev, struct spi_master *master) } EXPORT_SYMBOL_GPL(devm_spi_register_master);
+static int devm_spi_match_master(struct device *dev, void *res, void *master) +{ + return *(struct spi_master **)res == master; +} + static int __unregister(struct device *dev, void *null) { spi_unregister_device(to_spi_device(dev)); @@ -1928,7 +1973,14 @@ void spi_unregister_master(struct spi_master *master) list_del(&master->list); mutex_unlock(&board_lock);
- device_unregister(&master->dev); + device_del(&master->dev); + + /* Release the last reference on the master if its driver + * has not yet been converted to devm_spi_alloc_master(). + */ + if (!devres_find(master->dev.parent, devm_spi_release_master, + devm_spi_match_master, master)) + put_device(&master->dev); } EXPORT_SYMBOL_GPL(spi_unregister_master);
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index cce80e6dc7d1..f5d387140c46 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -568,6 +568,8 @@ extern void spi_finalize_current_transfer(struct spi_master *master); /* the spi driver core manages memory for the spi_master classdev */ extern struct spi_master * spi_alloc_master(struct device *host, unsigned size); +extern struct spi_master * +devm_spi_alloc_master(struct device *dev, unsigned int size);
extern int spi_register_master(struct spi_master *master); extern int devm_spi_register_master(struct device *dev,
[ Upstream commit e1483ac030fb4c57734289742f1c1d38dca61e22 ]
bcm2835_spi_remove() accesses the driver's private data after calling spi_unregister_controller() even though that function releases the last reference on the spi_controller and thereby frees the private data.
Fix by switching over to the new devm_spi_alloc_master() helper which keeps the private data accessible until the driver has unbound.
Fixes: f8043872e796 ("spi: add driver for BCM2835") Reported-by: Sascha Hauer s.hauer@pengutronix.de Reported-by: Florian Fainelli f.fainelli@gmail.com Signed-off-by: Lukas Wunner lukas@wunner.de Cc: stable@vger.kernel.org # v3.10+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation Cc: stable@vger.kernel.org # v3.10+ Cc: Vladimir Oltean olteanv@gmail.com Tested-by: Florian Fainelli f.fainelli@gmail.com Acked-by: Florian Fainelli f.fainelli@gmail.com Link: https://lore.kernel.org/r/ad66e0a0ad96feb848814842ecf5b6a4539ef35c.160512103... Signed-off-by: Mark Brown broonie@kernel.org --- drivers/spi/spi-bcm2835.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-)
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 27680b336454..d09a93257d65 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -742,7 +742,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev) struct resource *res; int err;
- master = spi_alloc_master(&pdev->dev, sizeof(*bs)); + master = devm_spi_alloc_master(&pdev->dev, sizeof(*bs)); if (!master) { dev_err(&pdev->dev, "spi_alloc_master() failed\n"); return -ENOMEM; @@ -764,23 +764,20 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
res = platform_get_resource(pdev, IORESOURCE_MEM, 0); bs->regs = devm_ioremap_resource(&pdev->dev, res); - if (IS_ERR(bs->regs)) { - err = PTR_ERR(bs->regs); - goto out_master_put; - } + if (IS_ERR(bs->regs)) + return PTR_ERR(bs->regs);
bs->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(bs->clk)) { err = PTR_ERR(bs->clk); dev_err(&pdev->dev, "could not get clk: %d\n", err); - goto out_master_put; + return err; }
bs->irq = platform_get_irq(pdev, 0); if (bs->irq <= 0) { dev_err(&pdev->dev, "could not get IRQ: %d\n", bs->irq); - err = bs->irq ? bs->irq : -ENODEV; - goto out_master_put; + return bs->irq ? bs->irq : -ENODEV; }
clk_prepare_enable(bs->clk); @@ -808,8 +805,6 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
out_clk_disable: clk_disable_unprepare(bs->clk); -out_master_put: - spi_master_put(master); return err; }
[ Upstream commit e13ee6cc4781edaf8c7321bee19217e3702ed481 ]
bcm2835aux_spi_remove() accesses the driver's private data after calling spi_unregister_master() even though that function releases the last reference on the spi_master and thereby frees the private data.
Fix by switching over to the new devm_spi_alloc_master() helper which keeps the private data accessible until the driver has unbound.
Fixes: b9dd3f6d4172 ("spi: bcm2835aux: Fix controller unregister order") Signed-off-by: Lukas Wunner lukas@wunner.de Cc: stable@vger.kernel.org # v4.4+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation Cc: stable@vger.kernel.org # v4.4+: b9dd3f6d4172: spi: bcm2835aux: Fix controller unregister order Cc: stable@vger.kernel.org # v4.4+ Link: https://lore.kernel.org/r/b290b06357d0c0bdee9cecc539b840a90630f101.160512103... Signed-off-by: Mark Brown broonie@kernel.org --- drivers/spi/spi-bcm2835aux.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-)
diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index 5ffc2765a8dd..0b5aff090b2e 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -381,7 +381,7 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev) unsigned long clk_hz; int err;
- master = spi_alloc_master(&pdev->dev, sizeof(*bs)); + master = devm_spi_alloc_master(&pdev->dev, sizeof(*bs)); if (!master) { dev_err(&pdev->dev, "spi_alloc_master() failed\n"); return -ENOMEM; @@ -411,30 +411,27 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev) /* the main area */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); bs->regs = devm_ioremap_resource(&pdev->dev, res); - if (IS_ERR(bs->regs)) { - err = PTR_ERR(bs->regs); - goto out_master_put; - } + if (IS_ERR(bs->regs)) + return PTR_ERR(bs->regs);
bs->clk = devm_clk_get(&pdev->dev, NULL); if ((!bs->clk) || (IS_ERR(bs->clk))) { err = PTR_ERR(bs->clk); dev_err(&pdev->dev, "could not get clk: %d\n", err); - goto out_master_put; + return err; }
bs->irq = platform_get_irq(pdev, 0); if (bs->irq <= 0) { dev_err(&pdev->dev, "could not get IRQ: %d\n", bs->irq); - err = bs->irq ? bs->irq : -ENODEV; - goto out_master_put; + return bs->irq ? bs->irq : -ENODEV; }
/* this also enables the HW block */ err = clk_prepare_enable(bs->clk); if (err) { dev_err(&pdev->dev, "could not prepare clock: %d\n", err); - goto out_master_put; + return err; }
/* just checking if the clock returns a sane value */ @@ -467,8 +464,6 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev)
out_clk_disable: clk_disable_unprepare(bs->clk); -out_master_put: - spi_master_put(master); return err; }
From: Peter Ujfalusi peter.ujfalusi@ti.com
[ Upstream commit 666224b43b4bd4612ce3b758c038f9bc5c5e3fcb ]
The DMA channel was not released if either devm_request_irq() or devm_spi_register_controller() failed.
Signed-off-by: Peter Ujfalusi peter.ujfalusi@ti.com Reviewed-by: Nicolas Saenz Julienne nsaenzjulienne@suse.de Link: https://lore.kernel.org/r/20191212135550.4634-3-peter.ujfalusi@ti.com Signed-off-by: Mark Brown broonie@kernel.org [lukas: backport to 4.19-stable] Signed-off-by: Lukas Wunner lukas@wunner.de --- drivers/spi/spi-bcm2835.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index d09a93257d65..dfbcaaaee66f 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -792,18 +792,19 @@ static int bcm2835_spi_probe(struct platform_device *pdev) dev_name(&pdev->dev), master); if (err) { dev_err(&pdev->dev, "could not request IRQ: %d\n", err); - goto out_clk_disable; + goto out_dma_release; }
err = spi_register_master(master); if (err) { dev_err(&pdev->dev, "could not register SPI master: %d\n", err); - goto out_clk_disable; + goto out_dma_release; }
return 0;
-out_clk_disable: +out_dma_release: + bcm2835_dma_release(master); clk_disable_unprepare(bs->clk); return err; }
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