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fa7e439cf9
Cgroup id is user provided datum hence extend its return domain to include possible error reason (similar to cgroup_get_from_fd()). This change also fixes commitd4ccaf58a8("bpf: Introduce cgroup iter") that would use NULL instead of proper error handling ind4ccaf58a8("bpf: Introduce cgroup iter"). Additionally, neither of: fc_appid_store, bpf_iter_attach_cgroup, mem_cgroup_get_from_ino (callers of cgroup_get_from_fd) is built without CONFIG_CGROUPS (depends via CONFIG_BLK_CGROUP, direct, transitive CONFIG_MEMCG respectively) transitive, so drop the singular definition not needed with !CONFIG_CGROUPS. Fixes:d4ccaf58a8("bpf: Introduce cgroup iter") Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
57 lines
1.4 KiB
C
57 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "blk-cgroup.h"
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/**
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* blkcg_set_fc_appid - set the fc_app_id field associted to blkcg
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* @app_id: application identifier
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* @cgrp_id: cgroup id
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* @app_id_len: size of application identifier
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*/
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int blkcg_set_fc_appid(char *app_id, u64 cgrp_id, size_t app_id_len)
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{
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struct cgroup *cgrp;
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struct cgroup_subsys_state *css;
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struct blkcg *blkcg;
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int ret = 0;
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if (app_id_len > FC_APPID_LEN)
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return -EINVAL;
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cgrp = cgroup_get_from_id(cgrp_id);
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if (IS_ERR(cgrp))
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return PTR_ERR(cgrp);
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css = cgroup_get_e_css(cgrp, &io_cgrp_subsys);
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if (!css) {
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ret = -ENOENT;
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goto out_cgrp_put;
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}
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blkcg = css_to_blkcg(css);
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/*
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* There is a slight race condition on setting the appid.
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* Worst case an I/O may not find the right id.
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* This is no different from the I/O we let pass while obtaining
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* the vmid from the fabric.
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* Adding the overhead of a lock is not necessary.
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*/
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strlcpy(blkcg->fc_app_id, app_id, app_id_len);
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css_put(css);
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out_cgrp_put:
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cgroup_put(cgrp);
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return ret;
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}
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EXPORT_SYMBOL_GPL(blkcg_set_fc_appid);
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/**
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* blkcg_get_fc_appid - get the fc app identifier associated with a bio
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* @bio: target bio
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*
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* On success return the fc_app_id, on failure return NULL
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*/
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char *blkcg_get_fc_appid(struct bio *bio)
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{
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if (!bio->bi_blkg || bio->bi_blkg->blkcg->fc_app_id[0] == '\0')
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return NULL;
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return bio->bi_blkg->blkcg->fc_app_id;
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}
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EXPORT_SYMBOL_GPL(blkcg_get_fc_appid);
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