Hi Praveen, On Tue, Nov 15, 2011 at 4:23 AM, Praveen kumar <chatpravi@xxxxxxxxx> wrote: > The driver is opened by multiple processes, One such process is a > diagnostics. > Where I am checking sanity of some of the registers if I make ioctl open for > all the processes.It can screw > up my diagnostics check.(write some values to registers). This is basic > reason I am using lock to my ioctl. So "locking the data" means that you should create a lock for the data registers in question. You should acquire the lock around writing the values to the registers, and presumably around reading them. Acquiring the lock is about accessing the registers, not calling the ioctl, even if today the only place that you access the registers is from the ioctl. What happens if down the road you decide to add some type of monitoring thread and it needs to access the registers? It's not in an ioctl, so acquiring some type of ioctl lock is misleading. The data that the lock is tied to is the registers, so make the code work that way. Also, som paths through the ioctl might not need to access the registers, so you don't need or want to acquire the lock for those cases. -- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
