Man page 9 : generic_pipe_buf_map

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 );

pipe
    the pipe that the buffer belongs to

buf
    the buffer that should be mapped

atomic
    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 calls kmap_atomic if atomic != 0.