struct pipe_inode_info — a linux kernel pipe
struct pipe_inode_info {
struct mutex mutex;
wait_queue_head_t wait;
unsigned int nrbufs;
unsigned int curbuf;
unsigned int buffers;
unsigned int readers;
unsigned int writers;
unsigned int files;
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 pipe_buffer * bufs;
}; mutex protecting the whole thing
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 struct file referring this pipe (protected by ->i_lock)
number of writers blocked waiting for room
reader counter
writer counter
cached released page
reader side fasync
writer side fasync
the circular array of pipe buffers