| 1 | |
| 2 |
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| 3 | #include "blk-cgroup.h"
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| 4 |
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| 5 | |
| 6 | * blkcg_set_fc_appid - set the fc_app_id field associted to blkcg
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| 7 | * @app_id: application identifier
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| 8 | * @cgrp_id: cgroup id
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| 9 | * @app_id_len: size of application identifier
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| 10 |
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| 11 | int blkcg_set_fc_appid(char *app_id, u64 cgrp_id, size_t app_id_len)
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| 12 | {
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| 13 | struct cgroup *cgrp;
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| 14 | struct cgroup_subsys_state *css;
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| 15 | struct blkcg *blkcg;
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| 16 | int ret = 0;
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| 17 |
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| 18 | if (app_id_len > FC_APPID_LEN)
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| 19 | return -EINVAL;
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| 20 |
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| 21 | cgrp = cgroup_get_from_id(cgrp_id);
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| 22 | if (IS_ERR(cgrp))
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| 23 | return PTR_ERR(cgrp);
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| 24 | css = cgroup_get_e_css(cgrp, &io_cgrp_subsys);
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| 25 | if (!css) {
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| 26 | ret = -ENOENT;
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| 27 | goto out_cgrp_put;
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| 28 | }
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| 29 | blkcg = css_to_blkcg(css);
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| 30 | |
| 31 | * There is a slight race condition on setting the appid.
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| 32 | * Worst case an I/O may not find the right id.
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| 33 | * This is no different from the I/O we let pass while obtaining
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| 34 | * the vmid from the fabric.
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| 35 | * Adding the overhead of a lock is not necessary.
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| 36 |
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| 37 | strscpy(blkcg->fc_app_id, app_id, app_id_len);
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| 38 | css_put(css);
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| 39 | out_cgrp_put:
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| 40 | cgroup_put(cgrp);
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| 41 | return ret;
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| 42 | }
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| 43 | EXPORT_SYMBOL_GPL(blkcg_set_fc_appid);
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| 44 |
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| 45 | |
| 46 | * blkcg_get_fc_appid - get the fc app identifier associated with a bio
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| 47 | * @bio: target bio
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| 48 | *
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| 49 | * On success return the fc_app_id, on failure return NULL
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| 50 |
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| 51 | char *blkcg_get_fc_appid(struct bio *bio)
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| 52 | {
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| 53 | if (!bio->bi_blkg || bio->bi_blkg->blkcg->fc_app_id[0] == '\0')
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| 54 | return NULL;
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| 55 | return bio->bi_blkg->blkcg->fc_app_id;
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| 56 | }
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| 57 | EXPORT_SYMBOL_GPL(blkcg_get_fc_appid);
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