flushing kernel space memory using sync/bdflush
 

We are using MPC8270 as processor an running linux 2.6.11. We are seeing unusual crashes/kernel panic in swapper, events/o and so on. We are calling IOCTL calls from the application continuously to read/write to the memory mapped FPGA Device. When printf/printk is given there is no problem but once they are removed i'm getting app/kernel crash. As of now I'm thinking if I could call sync/bdflush inside IOCTL function it could be useful. Could you help me how to include the header files for this? Is this supported for 2.6.x? Because in unistd.h sync function was not there ??? Kindly help me out and give some pointers on the Issue.If you need the source code pl mail me I'll send it across. Thanks in advance.