From mboxrd@z Thu Jan  1 00:00:00 1970
From: tobias@gambas-buch.de (Tobias Boege)
Date: Thu, 27 Dec 2012 12:13:45 +0100
Subject: Regarding ioctl()
In-Reply-To: <CA+NV+V=5PCJqL47XArNV8RZYBdW--R3mhnPLfNKpG5usE4tmdQ@mail.gmail.com>
References: <CA+NV+V=5PCJqL47XArNV8RZYBdW--R3mhnPLfNKpG5usE4tmdQ@mail.gmail.com>
Message-ID: <20121227111345.GC663@aurora>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

On Thu, 27 Dec 2012, Rahul Bedarkar wrote:
> Hi,
> 
> When ioctl() is called from user space, how device driver related to it
> comes into picture ? What is flow from user space to kernel space ?
> 

You may want to just follow the calls down from the syscall handler in
fs/ioctl.c. For special devices and non-handled ioctls you will end up in
vfs_ioctl() which calls the ->f_op->unlocked_ioctl() method of the backing
struct file defined in the driver, supposedly.

Regards,
Tobi