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1// SPDX-License-Identifier: GPL-2.02 3#include "blk-cgroup.h"4 5/**6 * blkcg_set_fc_appid - set the fc_app_id field associted to blkcg7 * @app_id: application identifier8 * @cgrp_id: cgroup id9 * @app_id_len: size of application identifier10 */11int 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 (IS_ERR(cgrp))23 return PTR_ERR(cgrp);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 obtaining34 * 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);39out_cgrp_put:40 cgroup_put(cgrp);41 return ret;42}43EXPORT_SYMBOL_GPL(blkcg_set_fc_appid);44 45/**46 * blkcg_get_fc_appid - get the fc app identifier associated with a bio47 * @bio: target bio48 *49 * On success return the fc_app_id, on failure return NULL50 */51char *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}57EXPORT_SYMBOL_GPL(blkcg_get_fc_appid);58