1 | // SPDX-License-Identifier: GPL-2.0 |
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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(id: cgrp_id); |
22 | if (IS_ERR(ptr: cgrp)) |
23 | return PTR_ERR(ptr: cgrp); |
24 | css = cgroup_get_e_css(cgroup: cgrp, ss: &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 | strscpy(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); |
58 |