Linux 6.13-rc4
[linux.git] / fs / bcachefs / thread_with_file.h
blob72497b9219113bb2dc9dc9e871d617029003605d
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _BCACHEFS_THREAD_WITH_FILE_H
3 #define _BCACHEFS_THREAD_WITH_FILE_H
5 #include "thread_with_file_types.h"
7 /*
8 * Thread with file: Run a kthread and connect it to a file descriptor, so that
9 * it can be interacted with via fd read/write methods and closing the file
10 * descriptor stops the kthread.
12 * We have two different APIs:
14 * thread_with_file, the low level version.
15 * You get to define the full file_operations, including your release function,
16 * which means that you must call bch2_thread_with_file_exit() from your
17 * .release method
19 * thread_with_stdio, the higher level version
20 * This implements full piping of input and output, including .poll.
22 * Notes on behaviour:
23 * - kthread shutdown behaves like writing or reading from a pipe that has been
24 * closed
25 * - Input and output buffers are 4096 bytes, although buffers may in some
26 * situations slightly exceed that limit so as to avoid chopping off a
27 * message in the middle in nonblocking mode.
28 * - Input/output buffers are lazily allocated, with GFP_NOWAIT allocations -
29 * should be fine but might change in future revisions.
30 * - Output buffer may grow past 4096 bytes to deal with messages that are
31 * bigger than 4096 bytes
32 * - Writing may be done blocking or nonblocking; in nonblocking mode, we only
33 * drop entire messages.
35 * To write, use stdio_redirect_printf()
36 * To read, use stdio_redirect_read() or stdio_redirect_readline()
39 struct task_struct;
41 struct thread_with_file {
42 struct task_struct *task;
43 int ret;
44 bool done;
47 void bch2_thread_with_file_exit(struct thread_with_file *);
48 int bch2_run_thread_with_file(struct thread_with_file *,
49 const struct file_operations *,
50 int (*fn)(void *));
52 struct thread_with_stdio;
54 struct thread_with_stdio_ops {
55 void (*exit)(struct thread_with_stdio *);
56 int (*fn)(struct thread_with_stdio *);
57 long (*unlocked_ioctl)(struct thread_with_stdio *, unsigned int, unsigned long);
60 struct thread_with_stdio {
61 struct thread_with_file thr;
62 struct stdio_redirect stdio;
63 const struct thread_with_stdio_ops *ops;
66 void bch2_thread_with_stdio_init(struct thread_with_stdio *,
67 const struct thread_with_stdio_ops *);
68 int __bch2_run_thread_with_stdio(struct thread_with_stdio *);
69 int bch2_run_thread_with_stdio(struct thread_with_stdio *,
70 const struct thread_with_stdio_ops *);
71 int bch2_run_thread_with_stdout(struct thread_with_stdio *,
72 const struct thread_with_stdio_ops *);
73 int bch2_stdio_redirect_read(struct stdio_redirect *, char *, size_t);
75 int bch2_stdio_redirect_readline_timeout(struct stdio_redirect *, darray_char *, unsigned long);
76 int bch2_stdio_redirect_readline(struct stdio_redirect *, darray_char *);
78 __printf(3, 0) ssize_t bch2_stdio_redirect_vprintf(struct stdio_redirect *, bool, const char *, va_list);
79 __printf(3, 4) ssize_t bch2_stdio_redirect_printf(struct stdio_redirect *, bool, const char *, ...);
81 #endif /* _BCACHEFS_THREAD_WITH_FILE_H */