diff options
Diffstat (limited to 'include/linux/pipe_fs_i.h')
| -rw-r--r-- | include/linux/pipe_fs_i.h | 135 |
1 files changed, 106 insertions, 29 deletions
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index 6cb65df3e3ba..7f6a92ac9704 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -31,13 +31,39 @@ struct pipe_buffer { 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_64BIT +typedef unsigned int pipe_index_t; +#else +typedef 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 - * @head: The point of buffer production - * @tail: The point of buffer consumption + * @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) @@ -58,13 +84,11 @@ struct pipe_buffer { struct pipe_inode_info { struct mutex mutex; wait_queue_head_t rd_wait, wr_wait; - unsigned int head; - unsigned int tail; + + union pipe_index; + unsigned int max_usage; unsigned int ring_size; -#ifdef CONFIG_WATCH_QUEUE - bool note_loss; -#endif unsigned int nr_accounted; unsigned int readers; unsigned int writers; @@ -72,7 +96,10 @@ struct pipe_inode_info { unsigned int r_counter; unsigned int w_counter; bool poll_usage; - struct page *tmp_page; +#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; @@ -125,13 +152,19 @@ struct pipe_buf_operations { }; /** - * pipe_empty - Return true if the pipe is empty - * @head: The pipe ring head pointer - * @tail: The pipe ring tail pointer + * 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_empty(unsigned int head, unsigned int tail) +static inline bool pipe_has_watch_queue(const struct pipe_inode_info *pipe) { - return head == tail; +#ifdef CONFIG_WATCH_QUEUE + return pipe->watch_queue != NULL; +#else + return false; +#endif } /** @@ -141,7 +174,17 @@ static inline bool pipe_empty(unsigned int head, unsigned int tail) */ static inline unsigned int pipe_occupancy(unsigned int head, unsigned int tail) { - return head - 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); } /** @@ -157,6 +200,53 @@ static inline bool pipe_full(unsigned int head, unsigned int tail, } /** + * 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 @@ -209,15 +299,6 @@ static inline bool pipe_buf_try_steal(struct pipe_inode_info *pipe, return buf->ops->try_steal(pipe, buf); } -static inline void pipe_discard_from(struct pipe_inode_info *pipe, - unsigned int old_head) -{ - unsigned int mask = pipe->ring_size - 1; - - while (pipe->head > old_head) - pipe_buf_release(pipe, &pipe->bufs[--pipe->head & mask]); -} - /* 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 @@ -241,22 +322,18 @@ void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *); extern const struct pipe_buf_operations nosteal_pipe_buf_ops; -#ifdef CONFIG_WATCH_QUEUE 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); -#endif /* for F_SETPIPE_SZ and F_GETPIPE_SZ */ -#ifdef CONFIG_WATCH_QUEUE int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots); -#endif -long pipe_fcntl(struct file *, unsigned int, unsigned long arg); +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 long size); +unsigned int round_pipe_size(unsigned int size); #endif |