// SPDX-License-Identifier: GPL-2.0 #include "blk-cgroup.h" /** * blkcg_set_fc_appid - set the fc_app_id field associted to blkcg * @app_id: application identifier * @cgrp_id: cgroup id * @app_id_len: size of application identifier */ int blkcg_set_fc_appid(char *app_id, u64 cgrp_id, size_t app_id_len) { struct cgroup *cgrp; struct cgroup_subsys_state *css; struct blkcg *blkcg; int ret = 0; if (app_id_len > FC_APPID_LEN) return -EINVAL; cgrp = cgroup_get_from_id(cgrp_id); if (!cgrp) return -ENOENT; css = cgroup_get_e_css(cgrp, &io_cgrp_subsys); if (!css) { ret = -ENOENT; goto out_cgrp_put; } blkcg = css_to_blkcg(css); /* * There is a slight race condition on setting the appid. * Worst case an I/O may not find the right id. * This is no different from the I/O we let pass while obtaining * the vmid from the fabric. * Adding the overhead of a lock is not necessary. */ strlcpy(blkcg->fc_app_id, app_id, app_id_len); css_put(css); out_cgrp_put: cgroup_put(cgrp); return ret; } EXPORT_SYMBOL_GPL(blkcg_set_fc_appid); /** * blkcg_get_fc_appid - get the fc app identifier associated with a bio * @bio: target bio * * On success return the fc_app_id, on failure return NULL */ char *blkcg_get_fc_appid(struct bio *bio) { if (!bio->bi_blkg || bio->bi_blkg->blkcg->fc_app_id[0] == '\0') return NULL; return bio->bi_blkg->blkcg->fc_app_id; } EXPORT_SYMBOL_GPL(blkcg_get_fc_appid);