diff options
Diffstat (limited to 'fs/bio.c')
| -rw-r--r-- | fs/bio.c | 61 |
1 files changed, 61 insertions, 0 deletions
@@ -19,12 +19,14 @@ #include <linux/swap.h> #include <linux/bio.h> #include <linux/blkdev.h> +#include <linux/iocontext.h> #include <linux/slab.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/mempool.h> #include <linux/workqueue.h> +#include <linux/cgroup.h> #include <scsi/sg.h> /* for struct sg_iovec */ #include <trace/events/block.h> @@ -418,6 +420,7 @@ void bio_put(struct bio *bio) * last put frees it */ if (atomic_dec_and_test(&bio->bi_cnt)) { + bio_disassociate_task(bio); bio->bi_next = NULL; bio->bi_destructor(bio); } @@ -1641,6 +1644,64 @@ bad: } EXPORT_SYMBOL(bioset_create); +#ifdef CONFIG_BLK_CGROUP +/** + * bio_associate_current - associate a bio with %current + * @bio: target bio + * + * Associate @bio with %current if it hasn't been associated yet. Block + * layer will treat @bio as if it were issued by %current no matter which + * task actually issues it. + * + * This function takes an extra reference of @task's io_context and blkcg + * which will be put when @bio is released. The caller must own @bio, + * ensure %current->io_context exists, and is responsible for synchronizing + * calls to this function. + */ +int bio_associate_current(struct bio *bio) +{ + struct io_context *ioc; + struct cgroup_subsys_state *css; + + if (bio->bi_ioc) + return -EBUSY; + + ioc = current->io_context; + if (!ioc) + return -ENOENT; + + /* acquire active ref on @ioc and associate */ + get_io_context_active(ioc); + bio->bi_ioc = ioc; + + /* associate blkcg if exists */ + rcu_read_lock(); + css = task_subsys_state(current, blkio_subsys_id); + if (css && css_tryget(css)) + bio->bi_css = css; + rcu_read_unlock(); + + return 0; +} + +/** + * bio_disassociate_task - undo bio_associate_current() + * @bio: target bio + */ +void bio_disassociate_task(struct bio *bio) +{ + if (bio->bi_ioc) { + put_io_context(bio->bi_ioc); + bio->bi_ioc = NULL; + } + if (bio->bi_css) { + css_put(bio->bi_css); + bio->bi_css = NULL; + } +} + +#endif /* CONFIG_BLK_CGROUP */ + static void __init biovec_init_slabs(void) { int i; |