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db056284 CH |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | ||
3 | #include "blk-cgroup.h" | |
4 | ||
5 | /** | |
6 | * blkcg_set_fc_appid - set the fc_app_id field associted to blkcg | |
7 | * @app_id: application identifier | |
8 | * @cgrp_id: cgroup id | |
9 | * @app_id_len: size of application identifier | |
10 | */ | |
11 | int blkcg_set_fc_appid(char *app_id, u64 cgrp_id, size_t app_id_len) | |
12 | { | |
13 | struct cgroup *cgrp; | |
14 | struct cgroup_subsys_state *css; | |
15 | struct blkcg *blkcg; | |
16 | int ret = 0; | |
17 | ||
18 | if (app_id_len > FC_APPID_LEN) | |
19 | return -EINVAL; | |
20 | ||
21 | cgrp = cgroup_get_from_id(cgrp_id); | |
22 | if (!cgrp) | |
23 | return -ENOENT; | |
24 | css = cgroup_get_e_css(cgrp, &io_cgrp_subsys); | |
25 | if (!css) { | |
26 | ret = -ENOENT; | |
27 | goto out_cgrp_put; | |
28 | } | |
29 | blkcg = css_to_blkcg(css); | |
30 | /* | |
31 | * There is a slight race condition on setting the appid. | |
32 | * Worst case an I/O may not find the right id. | |
33 | * This is no different from the I/O we let pass while obtaining | |
34 | * the vmid from the fabric. | |
35 | * Adding the overhead of a lock is not necessary. | |
36 | */ | |
37 | strlcpy(blkcg->fc_app_id, app_id, app_id_len); | |
38 | css_put(css); | |
39 | out_cgrp_put: | |
40 | cgroup_put(cgrp); | |
41 | return ret; | |
42 | } | |
43 | EXPORT_SYMBOL_GPL(blkcg_set_fc_appid); | |
44 | ||
45 | /** | |
46 | * blkcg_get_fc_appid - get the fc app identifier associated with a bio | |
47 | * @bio: target bio | |
48 | * | |
49 | * On success return the fc_app_id, on failure return NULL | |
50 | */ | |
51 | char *blkcg_get_fc_appid(struct bio *bio) | |
52 | { | |
53 | if (!bio->bi_blkg || bio->bi_blkg->blkcg->fc_app_id[0] == '\0') | |
54 | return NULL; | |
55 | return bio->bi_blkg->blkcg->fc_app_id; | |
56 | } | |
57 | EXPORT_SYMBOL_GPL(blkcg_get_fc_appid); |