Messages in this thread | | | Date | Sat, 2 Aug 2014 03:54:32 +0530 | Subject | Re: [Question: Drivers/base/core.c] Why dev->init_name = NULL in device_add function ? | From | Aniroop Mathur <> |
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On Sat, Aug 2, 2014 at 12:53 AM, Greg KH <gregkh@linuxfoundation.org> wrote: > On Fri, Aug 01, 2014 at 10:43:23PM +0530, Aniroop Mathur wrote: >> Dear Mr. Greg Kroah-Hartman and Linux Community, >> Greetings of the day !! :) >> >> I am Aniroop Mathur working on Linux Kernel for last two years. >> I am stuck at one point and could not find the solution over internet. >> I posted on linuxquestions.org too. >> So I need your help and suggestion for it. >> >> Can you please help in answering my query as below: >> >> ===================================================== >> In function device_add of /drivers/base/core.c file, it is mentioned: >> /* >> * for statically allocated devices, which should all be converted >> * some day, we need to initialize the name. We prevent reading back >> * the name, and force the use of dev_name() >> */ >> if (dev->init_name) { >> dev_set_name(dev, "%s", dev->init_name); >> dev->init_name = NULL; >> } >> >> >> Except forcing the use of dev_name to read device name, >> Is there any other reason to make init_name as NULL ? > > Why would you want init_name to not be NULL? >
Currently in kernel, we cannot set name of event node.
If dev->init_name is not set as NULL in device_add(), then I can easily set name of event node in evdev_dev.c file as below:
if(dev->init_name) { sprintf(dev->init_name, "event_%s", dev->init_name); } error = device_add(&evdev->dev);
And in some input device driver code, I will use like below: dev->init_name = "accelerometer"; input_register_device(dev);
So, overall output will be /dev/input/event<x> --> /dev/input/event_accelerometer sys/class/input/input<x> --> sys/class/input/accelerometer
In short, input and event node names are set just by adding one line, which i found quite efficient. There is other way also to set name of event node but it involves using extra variable and little more code, So I am looking for best solution possible. :)
>> And if it is not made NULL, is there any problem or side-effect ? > > Yes, people would start to use it thinking it was the real name of the > device, when it might not be. >
As the name itself nicely suggests, it is just a initial name. It may not be the final name as developer can change the name using dev_set_name. Also dev_name api is available to get final/current name of the device.
Thanks and Regards, Aniroop Mathur
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