Messages in this thread Patch in this message | | | Date | Mon, 7 Apr 2014 10:53:22 +0200 | From | Jean Delvare <> | Subject | [PATCH] driver core: Move driver_data back to struct device |
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Having to allocate memory as part of dev_set_drvdata() is a problem because that memory may never get freed if the device itself is not created. So move driver_data back to struct device.
This is a partial revert of commit b4028437.
Signed-off-by: Jean Delvare <jdelvare@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- Greg, we discussed that back in January (in a thread named "Freeing of dev->p") but I did not hear back from you and I can't see this fix in your driver-core tree.
As discussed in that thread, really reverting b4028437 might be an even better option, performance-wise. If we do that, we'll first have to update drivers/iommu/exynos-iommu.c and drivers/vfio/vfio.c to no longer check for the return value of dev_set_drvdata(). I can provide the patches, if you're fine with that.
drivers/base/base.h | 3 --- drivers/base/dd.c | 13 +++---------- include/linux/device.h | 4 ++++ 3 files changed, 7 insertions(+), 13 deletions(-)
--- linux-3.15-rc0.orig/drivers/base/base.h 2014-04-07 10:32:56.429667887 +0200 +++ linux-3.15-rc0/drivers/base/base.h 2014-04-07 10:32:59.598734941 +0200 @@ -63,8 +63,6 @@ struct driver_private { * binding of drivers which were unable to get all the resources needed by * the device; typically because it depends on another driver getting * probed first. - * @driver_data - private pointer for driver specific info. Will turn into a - * list soon. * @device - pointer back to the struct class that this structure is * associated with. * @@ -76,7 +74,6 @@ struct device_private { struct klist_node knode_driver; struct klist_node knode_bus; struct list_head deferred_probe; - void *driver_data; struct device *device; }; #define to_device_private_parent(obj) \ --- linux-3.15-rc0.orig/drivers/base/dd.c 2014-04-07 10:32:56.429667887 +0200 +++ linux-3.15-rc0/drivers/base/dd.c 2014-04-07 10:32:59.599734962 +0200 @@ -577,22 +577,15 @@ void driver_detach(struct device_driver */ void *dev_get_drvdata(const struct device *dev) { - if (dev && dev->p) - return dev->p->driver_data; + if (dev) + return dev->driver_data; return NULL; } EXPORT_SYMBOL(dev_get_drvdata); int dev_set_drvdata(struct device *dev, void *data) { - int error; - - if (!dev->p) { - error = device_private_init(dev); - if (error) - return error; - } - dev->p->driver_data = data; + dev->driver_data = data; return 0; } EXPORT_SYMBOL(dev_set_drvdata); --- linux-3.15-rc0.orig/include/linux/device.h 2014-04-07 10:32:56.429667887 +0200 +++ linux-3.15-rc0/include/linux/device.h 2014-04-07 10:32:59.599734962 +0200 @@ -679,6 +679,8 @@ struct acpi_dev_node { * variants, which GPIO pins act in what additional roles, and so * on. This shrinks the "Board Support Packages" (BSPs) and * minimizes board-specific #ifdefs in drivers. + * @driver_data: Private pointer for driver specific info. Will turn into a + * list soon. * @power: For device power management. * See Documentation/power/devices.txt for details. * @pm_domain: Provide callbacks that are executed during system suspend, @@ -740,6 +742,8 @@ struct device { device */ void *platform_data; /* Platform specific data, device core doesn't touch it */ + void *driver_data; /* Driver data, set and get with + dev_set/get_drvdata */ struct dev_pm_info power; struct dev_pm_domain *pm_domain;
-- Jean Delvare SUSE L3 Support
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