projects / lttng-modules.git / blame
| Commit | Line | Data |
|---|---|---|
| 7633c773 MJ |
1 | /* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only) |
| 2 | * | |
| 3 | * wrapper/genhd.c | |
| 4 | * | |
| 5 | * Wrapper around disk_part_iter_(init|next|exit). Using KALLSYMS to get the | |
| 6 | * addresses when available, else we need to have a kernel that exports this | |
| 7 | * function to GPL modules. This export was removed in 5.12. | |
| 8 | * | |
| 9 | * Copyright (C) 2021 Michael Jeanson <mjeanson@efficios.com> | |
| 10 | */ | |
| 11 | ||
| 12 | #include <lttng/kernel-version.h> | |
| 13 | #include <linux/module.h> | |
| 14 | #include <wrapper/genhd.h> | |
| 15 | ||
| 16 | #if (defined(CONFIG_KALLSYMS) && \ | |
| 17 | (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,12,0))) | |
| 18 | ||
| 19 | #include <wrapper/kallsyms.h> | |
| 20 | ||
| 21 | static | |
| 22 | void (*disk_part_iter_init_sym)(struct disk_part_iter *piter, struct gendisk *disk, | |
| 23 | unsigned int flags); | |
| 24 | ||
| 25 | static | |
| 26 | LTTNG_DISK_PART_TYPE *(*disk_part_iter_next_sym)(struct disk_part_iter *piter); | |
| 27 | ||
| 28 | static | |
| 29 | void (*disk_part_iter_exit_sym)(struct disk_part_iter *piter); | |
| 30 | ||
| 31 | /* | |
| 32 | * This wrapper has an 'int' return type instead of the original 'void', to be | |
| 33 | * able to report the symbol lookup failure to the caller. | |
| 34 | * | |
| 35 | * Return 0 on success, -1 on error. | |
| 36 | */ | |
| 37 | int wrapper_disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk, | |
| 38 | unsigned int flags) | |
| 39 | { | |
| 40 | if (!disk_part_iter_init_sym) | |
| 41 | disk_part_iter_init_sym = (void *) kallsyms_lookup_funcptr("disk_part_iter_init"); | |
| 42 | ||
| 43 | if (disk_part_iter_init_sym) { | |
| 44 | disk_part_iter_init_sym(piter, disk, flags); | |
| 45 | } else { | |
| 46 | printk_once(KERN_WARNING "LTTng: disk_part_iter_init symbol lookup failed.\n"); | |
| 47 | return -1; | |
| 48 | } | |
| 49 | return 0; | |
| 50 | } | |
| 51 | EXPORT_SYMBOL_GPL(wrapper_disk_part_iter_init); | |
| 52 | ||
| 53 | LTTNG_DISK_PART_TYPE *wrapper_disk_part_iter_next(struct disk_part_iter *piter) | |
| 54 | { | |
| 55 | if (!disk_part_iter_next_sym) | |
| 56 | disk_part_iter_next_sym = (void *) kallsyms_lookup_funcptr("disk_part_iter_next"); | |
| 57 | ||
| 58 | if (disk_part_iter_next_sym) { | |
| 59 | return disk_part_iter_next_sym(piter); | |
| 60 | } else { | |
| 61 | printk_once(KERN_WARNING "LTTng: disk_part_iter_next symbol lookup failed.\n"); | |
| 62 | return NULL; | |
| 63 | } | |
| 64 | } | |
| 65 | EXPORT_SYMBOL_GPL(wrapper_disk_part_iter_next); | |
| 66 | ||
| 67 | /* | |
| 68 | * We don't return an error on symbol lookup failure here because there is | |
| 69 | * nothing the caller can do to cleanup the iterator. | |
| 70 | */ | |
| 71 | void wrapper_disk_part_iter_exit(struct disk_part_iter *piter) | |
| 72 | { | |
| 73 | if (!disk_part_iter_exit_sym) | |
| 74 | disk_part_iter_exit_sym = (void *) kallsyms_lookup_funcptr("disk_part_iter_exit"); | |
| 75 | ||
| 76 | if (disk_part_iter_exit_sym) { | |
| 77 | disk_part_iter_exit_sym(piter); | |
| 78 | } else { | |
| 79 | printk_once(KERN_WARNING "LTTng: disk_part_iter_exit symbol lookup failed.\n"); | |
| 80 | } | |
| 81 | } | |
| 82 | EXPORT_SYMBOL_GPL(wrapper_disk_part_iter_exit); | |
| 83 | ||
| 84 | #else | |
| 85 | ||
| 86 | /* | |
| 87 | * This wrapper has an 'int' return type instead of the original 'void', so the | |
| 88 | * kallsyms variant can report the symbol lookup failure to the caller. | |
| 89 | * | |
| 90 | * This variant always succeeds and returns 0. | |
| 91 | */ | |
| 92 | int wrapper_disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk, | |
| 93 | unsigned int flags) | |
| 94 | { | |
| 95 | disk_part_iter_init(piter, disk, flags); | |
| 96 | return 0; | |
| 97 | } | |
| 98 | EXPORT_SYMBOL_GPL(wrapper_disk_part_iter_init); | |
| 99 | ||
| 100 | LTTNG_DISK_PART_TYPE *wrapper_disk_part_iter_next(struct disk_part_iter *piter) | |
| 101 | { | |
| 102 | return disk_part_iter_next(piter); | |
| 103 | } | |
| 104 | EXPORT_SYMBOL_GPL(wrapper_disk_part_iter_next); | |
| 105 | ||
| 106 | void wrapper_disk_part_iter_exit(struct disk_part_iter *piter) | |
| 107 | { | |
| 108 | disk_part_iter_exit(piter); | |
| 109 | } | |
| 110 | EXPORT_SYMBOL_GPL(wrapper_disk_part_iter_exit); | |
| 111 | #endif |