Something went wrong. Try again.
Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Something went wrong. Try again.
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340/* SPDX-License-Identifier: GPL-2.0 */#ifndef _LINUX_PIPE_FS_I_H#define _LINUX_PIPE_FS_I_H
#define PIPE_DEF_BUFFERS 16
#define PIPE_BUF_FLAG_LRU 0x01 /* page is on the LRU */#define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */#define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */#define PIPE_BUF_FLAG_PACKET 0x08 /* read() as a packet */#define PIPE_BUF_FLAG_CAN_MERGE 0x10 /* can merge buffers */#define PIPE_BUF_FLAG_WHOLE 0x20 /* read() must return entire buffer or error */#ifdef CONFIG_WATCH_QUEUE#define PIPE_BUF_FLAG_LOSS 0x40 /* Message loss happened after this buffer */#endif
/** * struct pipe_buffer - a linux kernel pipe buffer * @page: the page containing the data for the pipe buffer * @offset: offset of data inside the @page * @len: length of data inside the @page * @ops: operations associated with this buffer. See @pipe_buf_operations. * @flags: pipe buffer flags. See above. * @private: private data owned by the ops. **/struct pipe_buffer { struct page *page; unsigned int offset, len; const struct pipe_buf_operations *ops; unsigned int flags; unsigned long private;};
/* * Really only alpha needs 32-bit fields, but * might as well do it for 64-bit architectures * since that's what we've historically done, * and it makes 'head_tail' always be a simple * 'unsigned long'. */#ifdef CONFIG_64BITtypedef unsigned int pipe_index_t;#elsetypedef unsigned short pipe_index_t;#endif
/** * struct pipe_index - pipe indeces * @head: The point of buffer production * @tail: The point of buffer consumption * @head_tail: unsigned long union of @head and @tail */union pipe_index { unsigned long head_tail; struct { pipe_index_t head; pipe_index_t tail; };};
/** * struct pipe_inode_info - a linux kernel pipe * @mutex: mutex protecting the whole thing * @rd_wait: reader wait point in case of empty pipe * @wr_wait: writer wait point in case of full pipe * @pipe_index: the pipe indeces * @note_loss: The next read() should insert a data-lost message * @max_usage: The maximum number of slots that may be used in the ring * @ring_size: total number of buffers (should be a power of 2) * @nr_accounted: The amount this pipe accounts for in user->pipe_bufs * @tmp_page: cached released page * @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) * @r_counter: reader counter * @w_counter: writer counter * @poll_usage: is this pipe used for epoll, which has crazy wakeups? * @fasync_readers: reader side fasync * @fasync_writers: writer side fasync * @bufs: the circular array of pipe buffers * @user: the user who created this pipe * @watch_queue: If this pipe is a watch_queue, this is the stuff for that **/struct pipe_inode_info { struct mutex mutex; wait_queue_head_t rd_wait, wr_wait;
union pipe_index;
unsigned int max_usage; unsigned int ring_size; unsigned int nr_accounted; unsigned int readers; unsigned int writers; unsigned int files; unsigned int r_counter; unsigned int w_counter; bool poll_usage;#ifdef CONFIG_WATCH_QUEUE bool note_loss;#endif struct page *tmp_page[2]; struct fasync_struct *fasync_readers; struct fasync_struct *fasync_writers; struct pipe_buffer *bufs; struct user_struct *user;#ifdef CONFIG_WATCH_QUEUE struct watch_queue *watch_queue;#endif};
/* * Note on the nesting of these functions: * * ->confirm() * ->try_steal() * * That is, ->try_steal() must be called on a confirmed buffer. See below for * the meaning of each operation. Also see the kerneldoc in fs/pipe.c for the * pipe and generic variants of these hooks. */struct pipe_buf_operations { /* * ->confirm() verifies that the data in the pipe buffer is there * and that the contents are good. If the pages in the pipe belong * to a file system, we may need to wait for IO completion in this * hook. Returns 0 for good, or a negative error value in case of * error. If not present all pages are considered good. */ int (*confirm)(struct pipe_inode_info *, struct pipe_buffer *);
/* * When the contents of this pipe buffer has been completely * consumed by a reader, ->release() is called. */ void (*release)(struct pipe_inode_info *, struct pipe_buffer *);
/* * Attempt to take ownership of the pipe buffer and its contents. * ->try_steal() returns %true for success, in which case the contents * of the pipe (the buf->page) is locked and now completely owned by the * caller. The page may then be transferred to a different mapping, the * most often used case is insertion into different file address space * cache. */ bool (*try_steal)(struct pipe_inode_info *, struct pipe_buffer *);
/* * Get a reference to the pipe buffer. */ bool (*get)(struct pipe_inode_info *, struct pipe_buffer *);};
/** * pipe_has_watch_queue - Check whether the pipe is a watch_queue, * i.e. it was created with O_NOTIFICATION_PIPE * @pipe: The pipe to check * * Return: true if pipe is a watch queue, false otherwise. */static inline bool pipe_has_watch_queue(const struct pipe_inode_info *pipe){#ifdef CONFIG_WATCH_QUEUE return pipe->watch_queue != NULL;#else return false;#endif}
/** * pipe_occupancy - Return number of slots used in the pipe * @head: The pipe ring head pointer * @tail: The pipe ring tail pointer */static inline unsigned int pipe_occupancy(unsigned int head, unsigned int tail){ return (pipe_index_t)(head - tail);}
/** * pipe_empty - Return true if the pipe is empty * @head: The pipe ring head pointer * @tail: The pipe ring tail pointer */static inline bool pipe_empty(unsigned int head, unsigned int tail){ return !pipe_occupancy(head, tail);}
/** * pipe_full - Return true if the pipe is full * @head: The pipe ring head pointer * @tail: The pipe ring tail pointer * @limit: The maximum amount of slots available. */static inline bool pipe_full(unsigned int head, unsigned int tail, unsigned int limit){ return pipe_occupancy(head, tail) >= limit;}
/** * pipe_is_full - Return true if the pipe is full * @pipe: the pipe */static inline bool pipe_is_full(const struct pipe_inode_info *pipe){ return pipe_full(pipe->head, pipe->tail, pipe->max_usage);}
/** * pipe_is_empty - Return true if the pipe is empty * @pipe: the pipe */static inline bool pipe_is_empty(const struct pipe_inode_info *pipe){ return pipe_empty(pipe->head, pipe->tail);}
/** * pipe_buf_usage - Return how many pipe buffers are in use * @pipe: the pipe */static inline unsigned int pipe_buf_usage(const struct pipe_inode_info *pipe){ return pipe_occupancy(pipe->head, pipe->tail);}
/** * pipe_buf - Return the pipe buffer for the specified slot in the pipe ring * @pipe: The pipe to access * @slot: The slot of interest */static inline struct pipe_buffer *pipe_buf(const struct pipe_inode_info *pipe, unsigned int slot){ return &pipe->bufs[slot & (pipe->ring_size - 1)];}
/** * pipe_head_buf - Return the pipe buffer at the head of the pipe ring * @pipe: The pipe to access */static inline struct pipe_buffer *pipe_head_buf(const struct pipe_inode_info *pipe){ return pipe_buf(pipe, pipe->head);}
/** * pipe_buf_get - get a reference to a pipe_buffer * @pipe: the pipe that the buffer belongs to * @buf: the buffer to get a reference to * * Return: %true if the reference was successfully obtained. */static inline __must_check bool pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf){ return buf->ops->get(pipe, buf);}
/** * pipe_buf_release - put a reference to a pipe_buffer * @pipe: the pipe that the buffer belongs to * @buf: the buffer to put a reference to */static inline void pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf){ const struct pipe_buf_operations *ops = buf->ops;
buf->ops = NULL; ops->release(pipe, buf);}
/** * pipe_buf_confirm - verify contents of the pipe buffer * @pipe: the pipe that the buffer belongs to * @buf: the buffer to confirm */static inline int pipe_buf_confirm(struct pipe_inode_info *pipe, struct pipe_buffer *buf){ if (!buf->ops->confirm) return 0; return buf->ops->confirm(pipe, buf);}
/** * pipe_buf_try_steal - attempt to take ownership of a pipe_buffer * @pipe: the pipe that the buffer belongs to * @buf: the buffer to attempt to steal */static inline bool pipe_buf_try_steal(struct pipe_inode_info *pipe, struct pipe_buffer *buf){ if (!buf->ops->try_steal) return false; return buf->ops->try_steal(pipe, buf);}
/* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual memory allocation, whereas PIPE_BUF makes atomicity guarantees. */#define PIPE_SIZE PAGE_SIZE
/* Pipe lock and unlock operations */void pipe_lock(struct pipe_inode_info *);void pipe_unlock(struct pipe_inode_info *);void pipe_double_lock(struct pipe_inode_info *, struct pipe_inode_info *);
/* Wait for a pipe to be readable/writable while dropping the pipe lock */void pipe_wait_readable(struct pipe_inode_info *);void pipe_wait_writable(struct pipe_inode_info *);
struct pipe_inode_info *alloc_pipe_info(void);void free_pipe_info(struct pipe_inode_info *);
/* Generic pipe buffer ops functions */bool generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);bool generic_pipe_buf_try_steal(struct pipe_inode_info *, struct pipe_buffer *);void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *);
extern const struct pipe_buf_operations nosteal_pipe_buf_ops;
unsigned long account_pipe_buffers(struct user_struct *user, unsigned long old, unsigned long new);bool too_many_pipe_buffers_soft(unsigned long user_bufs);bool too_many_pipe_buffers_hard(unsigned long user_bufs);bool pipe_is_unprivileged_user(void);
/* for F_SETPIPE_SZ and F_GETPIPE_SZ */int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots);long pipe_fcntl(struct file *, unsigned int, unsigned int arg);struct pipe_inode_info *get_pipe_info(struct file *file, bool for_splice);
int create_pipe_files(struct file **, int);unsigned int round_pipe_size(unsigned int size);
#endif