splice.h 3.0 KB

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  1. /* SPDX-License-Identifier: GPL-2.0 */
  2. /*
  3. * Function declerations and data structures related to the splice
  4. * implementation.
  5. *
  6. * Copyright (C) 2007 Jens Axboe <jens.axboe@oracle.com>
  7. *
  8. */
  9. #ifndef SPLICE_H
  10. #define SPLICE_H
  11. #include <linux/pipe_fs_i.h>
  12. /*
  13. * Flags passed in from splice/tee/vmsplice
  14. */
  15. #define SPLICE_F_MOVE (0x01) /* move pages instead of copying */
  16. #define SPLICE_F_NONBLOCK (0x02) /* don't block on the pipe splicing (but */
  17. /* we may still block on the fd we splice */
  18. /* from/to, of course */
  19. #define SPLICE_F_MORE (0x04) /* expect more data */
  20. #define SPLICE_F_GIFT (0x08) /* pages passed in are a gift */
  21. #define SPLICE_F_ALL (SPLICE_F_MOVE|SPLICE_F_NONBLOCK|SPLICE_F_MORE|SPLICE_F_GIFT)
  22. /*
  23. * Passed to the actors
  24. */
  25. struct splice_desc {
  26. size_t total_len; /* remaining length */
  27. unsigned int len; /* current length */
  28. unsigned int flags; /* splice flags */
  29. /*
  30. * actor() private data
  31. */
  32. union {
  33. void __user *userptr; /* memory to write to */
  34. struct file *file; /* file to read/write */
  35. void *data; /* cookie */
  36. } u;
  37. loff_t pos; /* file position */
  38. loff_t *opos; /* sendfile: output position */
  39. size_t num_spliced; /* number of bytes already spliced */
  40. bool need_wakeup; /* need to wake up writer */
  41. };
  42. struct partial_page {
  43. unsigned int offset;
  44. unsigned int len;
  45. unsigned long private;
  46. };
  47. /*
  48. * Passed to splice_to_pipe
  49. */
  50. struct splice_pipe_desc {
  51. struct page **pages; /* page map */
  52. struct partial_page *partial; /* pages[] may not be contig */
  53. int nr_pages; /* number of populated pages in map */
  54. unsigned int nr_pages_max; /* pages[] & partial[] arrays size */
  55. const struct pipe_buf_operations *ops;/* ops associated with output pipe */
  56. void (*spd_release)(struct splice_pipe_desc *, unsigned int);
  57. };
  58. typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
  59. struct splice_desc *);
  60. typedef int (splice_direct_actor)(struct pipe_inode_info *,
  61. struct splice_desc *);
  62. extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
  63. loff_t *, size_t, unsigned int,
  64. splice_actor *);
  65. extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
  66. struct splice_desc *, splice_actor *);
  67. extern ssize_t splice_to_pipe(struct pipe_inode_info *,
  68. struct splice_pipe_desc *);
  69. extern ssize_t add_to_pipe(struct pipe_inode_info *,
  70. struct pipe_buffer *);
  71. extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
  72. splice_direct_actor *);
  73. extern long do_splice(struct file *in, loff_t *off_in,
  74. struct file *out, loff_t *off_out,
  75. size_t len, unsigned int flags);
  76. extern long do_tee(struct file *in, struct file *out, size_t len,
  77. unsigned int flags);
  78. /*
  79. * for dynamic pipe sizing
  80. */
  81. extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *);
  82. extern void splice_shrink_spd(struct splice_pipe_desc *);
  83. extern const struct pipe_buf_operations page_cache_pipe_buf_ops;
  84. extern const struct pipe_buf_operations default_pipe_buf_ops;
  85. #endif