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1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef _BCACHEFS_THREAD_WITH_FILE_H3#define _BCACHEFS_THREAD_WITH_FILE_H4 5#include "thread_with_file_types.h"6 7/*8 * Thread with file: Run a kthread and connect it to a file descriptor, so that9 * it can be interacted with via fd read/write methods and closing the file10 * descriptor stops the kthread.11 *12 * We have two different APIs:13 *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 your17 * .release method18 *19 * thread_with_stdio, the higher level version20 * This implements full piping of input and output, including .poll.21 *22 * Notes on behaviour:23 * - kthread shutdown behaves like writing or reading from a pipe that has been24 * closed25 * - Input and output buffers are 4096 bytes, although buffers may in some26 * situations slightly exceed that limit so as to avoid chopping off a27 * 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 are31 * bigger than 4096 bytes32 * - Writing may be done blocking or nonblocking; in nonblocking mode, we only33 * drop entire messages.34 *35 * To write, use stdio_redirect_printf()36 * To read, use stdio_redirect_read() or stdio_redirect_readline()37 */38 39struct task_struct;40 41struct thread_with_file {42 struct task_struct *task;43 int ret;44 bool done;45};46 47void bch2_thread_with_file_exit(struct thread_with_file *);48int bch2_run_thread_with_file(struct thread_with_file *,49 const struct file_operations *,50 int (*fn)(void *));51 52struct thread_with_stdio;53 54struct 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);58};59 60struct thread_with_stdio {61 struct thread_with_file thr;62 struct stdio_redirect stdio;63 const struct thread_with_stdio_ops *ops;64};65 66void bch2_thread_with_stdio_init(struct thread_with_stdio *,67 const struct thread_with_stdio_ops *);68int __bch2_run_thread_with_stdio(struct thread_with_stdio *);69int bch2_run_thread_with_stdio(struct thread_with_stdio *,70 const struct thread_with_stdio_ops *);71int bch2_run_thread_with_stdout(struct thread_with_stdio *,72 const struct thread_with_stdio_ops *);73int bch2_stdio_redirect_read(struct stdio_redirect *, char *, size_t);74 75int bch2_stdio_redirect_readline_timeout(struct stdio_redirect *, darray_char *, unsigned long);76int bch2_stdio_redirect_readline(struct stdio_redirect *, darray_char *);77 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 *, ...);80 81#endif /* _BCACHEFS_THREAD_WITH_FILE_H */82