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author | Nicolas Saenz Julienne <nsaenzjulienne@suse.de> | 2021-01-18 13:32:34 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-15 09:50:41 +0200 |
commit | 60831f5ae6c713afceb6d29f40899ed112f36059 (patch) | |
tree | 081d4dd0cc7bbf7e02a5667c9c87ab1f84faaae3 /drivers/firmware | |
parent | 5c68b7795b4c7bdbd54148c9343b5a5edeb476d7 (diff) | |
download | linux-stable-60831f5ae6c713afceb6d29f40899ed112f36059.tar.gz linux-stable-60831f5ae6c713afceb6d29f40899ed112f36059.tar.bz2 linux-stable-60831f5ae6c713afceb6d29f40899ed112f36059.zip |
firmware: raspberrypi: Keep count of all consumers
[ Upstream commit 1e7c57355a3bc617fc220234889e49fe722a6305 ]
When unbinding the firmware device we need to make sure it has no
consumers left. Otherwise we'd leave them with a firmware handle
pointing at freed memory.
Keep a reference count of all consumers and introduce rpi_firmware_put()
which will permit automatically decrease the reference count upon
unbinding consumer drivers.
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/firmware')
-rw-r--r-- | drivers/firmware/raspberrypi.c | 40 |
1 files changed, 37 insertions, 3 deletions
diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c index 2371d08bdd17..8996deadd79b 100644 --- a/drivers/firmware/raspberrypi.c +++ b/drivers/firmware/raspberrypi.c @@ -7,6 +7,7 @@ */ #include <linux/dma-mapping.h> +#include <linux/kref.h> #include <linux/mailbox_client.h> #include <linux/module.h> #include <linux/of_platform.h> @@ -27,6 +28,8 @@ struct rpi_firmware { struct mbox_chan *chan; /* The property channel. */ struct completion c; u32 enabled; + + struct kref consumers; }; static DEFINE_MUTEX(transaction_lock); @@ -225,12 +228,31 @@ static void rpi_register_clk_driver(struct device *dev) -1, NULL, 0); } +static void rpi_firmware_delete(struct kref *kref) +{ + struct rpi_firmware *fw = container_of(kref, struct rpi_firmware, + consumers); + + mbox_free_channel(fw->chan); + kfree(fw); +} + +void rpi_firmware_put(struct rpi_firmware *fw) +{ + kref_put(&fw->consumers, rpi_firmware_delete); +} +EXPORT_SYMBOL_GPL(rpi_firmware_put); + static int rpi_firmware_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct rpi_firmware *fw; - fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL); + /* + * Memory will be freed by rpi_firmware_delete() once all users have + * released their firmware handles. Don't use devm_kzalloc() here. + */ + fw = kzalloc(sizeof(*fw), GFP_KERNEL); if (!fw) return -ENOMEM; @@ -247,6 +269,7 @@ static int rpi_firmware_probe(struct platform_device *pdev) } init_completion(&fw->c); + kref_init(&fw->consumers); platform_set_drvdata(pdev, fw); @@ -275,7 +298,8 @@ static int rpi_firmware_remove(struct platform_device *pdev) rpi_hwmon = NULL; platform_device_unregister(rpi_clk); rpi_clk = NULL; - mbox_free_channel(fw->chan); + + rpi_firmware_put(fw); return 0; } @@ -284,16 +308,26 @@ static int rpi_firmware_remove(struct platform_device *pdev) * rpi_firmware_get - Get pointer to rpi_firmware structure. * @firmware_node: Pointer to the firmware Device Tree node. * + * The reference to rpi_firmware has to be released with rpi_firmware_put(). + * * Returns NULL is the firmware device is not ready. */ struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node) { struct platform_device *pdev = of_find_device_by_node(firmware_node); + struct rpi_firmware *fw; if (!pdev) return NULL; - return platform_get_drvdata(pdev); + fw = platform_get_drvdata(pdev); + if (!fw) + return NULL; + + if (!kref_get_unless_zero(&fw->consumers)) + return NULL; + + return fw; } EXPORT_SYMBOL_GPL(rpi_firmware_get); |