| 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(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(p: blkcg->fc_app_id, q: app_id, size: 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 |