[PATCH AUTOSEL 5.4 02/31] spi: Fix spi device unregister flow

[PATCH AUTOSEL 5.4 02/31] spi: Fix spi device unregister flow

[Sasha Levin]

From: Saravana Kannan <saravanak@google.com>

[ Upstream commit c7299fea67696db5bd09d924d1f1080d894f92ef ]

When an SPI device is unregistered, the spi->controller->cleanup() is
called in the device's release callback. That's wrong for a couple of
reasons:

1. spi_dev_put() can be called before spi_add_device() is called. And
   it's spi_add_device() that calls spi_setup(). This will cause clean()
   to get called without the spi device ever being setup.

2. There's no guarantee that the controller's driver would be present by
   the time the spi device's release function gets called.

3. It also causes "sleeping in atomic context" stack dump[1] when device
   link deletion code does a put_device() on the spi device.

Fix these issues by simply moving the cleanup from the device release
callback to the actual spi_unregister_device() function.

[1] - https://lore.kernel.org/lkml/CAHp75Vc=FCGcUyS0v6fnxme2YJ+qD+Y-hQDQLa2JhWNON9VmsQ@mail.gmail.com/

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210426235638.1285530-1-saravanak@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 7592d4de20c9..c4b80cf825b8 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -47,10 +47,6 @@ static void spidev_release(struct device *dev)
 {
 	struct spi_device	*spi = to_spi_device(dev);
 
-	/* spi controllers may cleanup for released devices */
-	if (spi->controller->cleanup)
-		spi->controller->cleanup(spi);
-
 	spi_controller_put(spi->controller);
 	kfree(spi->driver_override);
 	kfree(spi);
@@ -549,6 +545,12 @@ static int spi_dev_check(struct device *dev, void *data)
 	return 0;
 }
 
+static void spi_cleanup(struct spi_device *spi)
+{
+	if (spi->controller->cleanup)
+		spi->controller->cleanup(spi);
+}
+
 /**
  * spi_add_device - Add spi_device allocated with spi_alloc_device
  * @spi: spi_device to register
@@ -613,11 +615,13 @@ int spi_add_device(struct spi_device *spi)
 
 	/* Device may be bound to an active driver when this returns */
 	status = device_add(&spi->dev);
-	if (status < 0)
+	if (status < 0) {
 		dev_err(dev, "can't add %s, status %d\n",
 				dev_name(&spi->dev), status);
-	else
+		spi_cleanup(spi);
+	} else {
 		dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
+	}
 
 done:
 	mutex_unlock(&spi_add_lock);
@@ -704,6 +708,8 @@ void spi_unregister_device(struct spi_device *spi)
 	if (!spi)
 		return;
 
+	spi_cleanup(spi);
+
 	if (spi->dev.of_node) {
 		of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 		of_node_put(spi->dev.of_node);
-- 
2.30.2

[PATCH AUTOSEL 5.4 09/31] spi: sprd: Add missing MODULE_DEVICE_TABLE

[Sasha Levin]

From: Chunyan Zhang <chunyan.zhang@unisoc.com>

[ Upstream commit 7907cad7d07e0055789ec0c534452f19dfe1fc80 ]

MODULE_DEVICE_TABLE is used to extract the device information out of the
driver and builds a table when being compiled. If using this macro,
kernel can find the driver if available when the device is plugged in,
and then loads that driver and initializes the device.

Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Link: https://lore.kernel.org/r/20210512093534.243040-1-zhang.lyra@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-sprd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/spi/spi-sprd.c b/drivers/spi/spi-sprd.c
index c2bdf19ccdd2..44dc7b5b45ad 100644
--- a/drivers/spi/spi-sprd.c
+++ b/drivers/spi/spi-sprd.c
@@ -1066,6 +1066,7 @@ static const struct of_device_id sprd_spi_of_match[] = {
 	{ .compatible = "sprd,sc9860-spi", },
 	{ /* sentinel */ }
 };
+MODULE_DEVICE_TABLE(of, sprd_spi_of_match);
 
 static struct platform_driver sprd_spi_driver = {
 	.driver = {
-- 
2.30.2