struct_pipe_inode_info (9)

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;
#ifndef __GENKSYMS__
  struct user_struct * user;
#endif
};

mutex

mutex protecting the whole thing

wait

reader/writer wait point in case of empty/full pipe

nrbufs

the number of non-empty pipe buffers in this pipe

curbuf

the current pipe buffer entry

buffers

total number of buffers (should be a power of 2)

readers

number of current readers of this pipe

writers

number of current writers of this pipe

files

number of struct file referring this pipe (protected by ->i_lock)

waiting_writers

number of writers blocked waiting for room

r_counter

reader counter

w_counter

writer counter

tmp_page

cached released page

fasync_readers

reader side fasync

fasync_writers

writer side fasync

bufs

the circular array of pipe buffers

user

the user who created this pipe