On 22/08/14 12:37, David Herrmann wrote:
Hi On Fri, Aug 22, 2014 at 1:29 PM, Sudeep Holla <sudeep.ho...@arm.com> wrote:From: Sudeep Holla <sudeep.ho...@arm.com> This patch adds a new function to create per-cpu devices. This helps in: 1. reusing the device infrastructure to create any cpu related attributes and corresponding sysfs instead of creating and dealing with raw kobjects directly 2. retaining the legacy path(/sys/devices/system/cpu/..) to support existing sysfs ABI 3. avoiding to create links in the bus directory pointing to the device as there would be per-cpu instance of these devices with the same name since dev->bus is not populated to cpu_sysbus on purpose Signed-off-by: Sudeep Holla <sudeep.ho...@arm.com> Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- drivers/base/cpu.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/cpu.h | 4 ++++ 2 files changed, 58 insertions(+) Hi Greg, Here is the alternate solution I could come up with instead of creating cpu class. cpu_device_create is very similar to device_create_groups_vargs w/o class support, but I could not reuse anything else to avoid creating similar function. Let me know your thoughts/suggestions on this. Regards, Sudeep diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 277a9cfa9040..53f0c4141d05 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -363,6 +363,60 @@ struct device *get_cpu_device(unsigned cpu) } EXPORT_SYMBOL_GPL(get_cpu_device); +static void device_create_release(struct device *dev) +{ + kfree(dev); +} + +static struct device * +__cpu_device_create(struct device *parent, void *drvdata, + const struct attribute_group **groups, + const char *fmt, va_list args) +{ + struct device *dev = NULL; + int retval = -ENODEV; + + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) { + retval = -ENOMEM; + goto error; + } + + device_initialize(dev); + dev->parent = parent; + dev->groups = groups; + dev->release = device_create_release; + dev_set_drvdata(dev, drvdata); + + retval = kobject_set_name_vargs(&dev->kobj, fmt, args); + if (retval) + goto error; + + retval = device_add(dev); + if (retval) + goto error;Exactly! As I said, simply setting dev->groups before calling device_add(). However, I really don't understand why we need this as global API.
Yes right now it's used only in cacheinfo. The main reason why I am exporting it is that we can reuse it in some places like cpuidle/freq which deals with raw kobjects directly and can be moved to device attributes.
Skimming over the other patches, you use cpu_device_create() only in one place. Why not hard-code this all there? It is totally OK to do device initialization in drivers. All the helpers (like device_create(), device_create_with_groups(), and so on) are just convenience functions. The driver-core API explicitly allows drivers to initialize devices manually. Nevertheless, this patch looks fine.
Thanks for having a look at this. Regards, Sudeep -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
