generic_pipe_buf_map — virtually map a pipe buffer
void * generic_pipe_buf_map
(struct pipe_inode_info * pipe, struct pipe_buffer * buf, int atomic);
the pipe that the buffer belongs to
the buffer that should be mapped
whether to use an atomic map
This function returns a kernel virtual address mapping for the pipe_buffer passed in buf. If atomic is set, an atomic map is provided and the caller has to be careful not to fault before calling the unmap function.
Note that this function occupies KM_USER0 if atomic != 0.