struct pipe_inode_info — a linux kernel pipe
struct pipe_inode_info {
wait_queue_head_t wait;
unsigned int nrbufs;
unsigned int curbuf;
unsigned int buffers;
unsigned int readers;
unsigned int writers;
unsigned int waiting_writers;
unsigned int r_counter;
unsigned int w_counter;
struct page * tmp_page;
struct fasync_struct * fasync_readers;
struct fasync_struct * fasync_writers;
struct inode * inode;
struct pipe_buffer * bufs;
}; reader/writer wait point in case of empty/full pipe
the number of non-empty pipe buffers in this pipe
the current pipe buffer entry
total number of buffers (should be a power of 2)
number of current readers of this pipe
number of current writers of this pipe
number of writers blocked waiting for room
reader counter
writer counter
cached released page
reader side fasync
writer side fasync
inode this pipe is attached to
the circular array of pipe buffers