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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-30 08:52:42 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-30 08:52:42 -0700 |
commit | 0d167518e045cc8bb63f0a8a0a85ad4fa4e0044f (patch) | |
tree | 101a9b5d425d79f663e4f25f1e90b7a8cc6604f1 /include/linux/iocontext.h | |
parent | Merge tag 'iommu-updates-v3.5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu (diff) | |
parent | blkcg: tg_stats_alloc_lock is an irq lock (diff) | |
download | linux-dev-0d167518e045cc8bb63f0a8a0a85ad4fa4e0044f.tar.xz linux-dev-0d167518e045cc8bb63f0a8a0a85ad4fa4e0044f.zip |
Merge branch 'for-3.5/core' of git://git.kernel.dk/linux-block
Merge block/IO core bits from Jens Axboe:
"This is a bit bigger on the core side than usual, but that is purely
because we decided to hold off on parts of Tejun's submission on 3.4
to give it a bit more time to simmer. As a consequence, it's seen a
long cycle in for-next.
It contains:
- Bug fix from Dan, wrong locking type.
- Relax splice gifting restriction from Eric.
- A ton of updates from Tejun, primarily for blkcg. This improves
the code a lot, making the API nicer and cleaner, and also includes
fixes for how we handle and tie policies and re-activate on
switches. The changes also include generic bug fixes.
- A simple fix from Vivek, along with a fix for doing proper delayed
allocation of the blkcg stats."
Fix up annoying conflict just due to different merge resolution in
Documentation/feature-removal-schedule.txt
* 'for-3.5/core' of git://git.kernel.dk/linux-block: (92 commits)
blkcg: tg_stats_alloc_lock is an irq lock
vmsplice: relax alignement requirements for SPLICE_F_GIFT
blkcg: use radix tree to index blkgs from blkcg
blkcg: fix blkcg->css ref leak in __blkg_lookup_create()
block: fix elvpriv allocation failure handling
block: collapse blk_alloc_request() into get_request()
blkcg: collapse blkcg_policy_ops into blkcg_policy
blkcg: embed struct blkg_policy_data in policy specific data
blkcg: mass rename of blkcg API
blkcg: style cleanups for blk-cgroup.h
blkcg: remove blkio_group->path[]
blkcg: blkg_rwstat_read() was missing inline
blkcg: shoot down blkgs if all policies are deactivated
blkcg: drop stuff unused after per-queue policy activation update
blkcg: implement per-queue policy activation
blkcg: add request_queue->root_blkg
blkcg: make request_queue bypassing on allocation
blkcg: make sure blkg_lookup() returns %NULL if @q is bypassing
blkcg: make blkg_conf_prep() take @pol and return with queue lock held
blkcg: remove static policy ID enums
...
Diffstat (limited to 'include/linux/iocontext.h')
-rw-r--r-- | include/linux/iocontext.h | 39 |
1 files changed, 22 insertions, 17 deletions
diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h index 1a3018063034..df38db2ef45b 100644 --- a/include/linux/iocontext.h +++ b/include/linux/iocontext.h @@ -6,11 +6,7 @@ #include <linux/workqueue.h> enum { - ICQ_IOPRIO_CHANGED = 1 << 0, - ICQ_CGROUP_CHANGED = 1 << 1, ICQ_EXITED = 1 << 2, - - ICQ_CHANGED_MASK = ICQ_IOPRIO_CHANGED | ICQ_CGROUP_CHANGED, }; /* @@ -100,6 +96,7 @@ struct io_cq { */ struct io_context { atomic_long_t refcount; + atomic_t active_ref; atomic_t nr_tasks; /* all the fields below are protected by this lock */ @@ -120,29 +117,37 @@ struct io_context { struct work_struct release_work; }; -static inline struct io_context *ioc_task_link(struct io_context *ioc) +/** + * get_io_context_active - get active reference on ioc + * @ioc: ioc of interest + * + * Only iocs with active reference can issue new IOs. This function + * acquires an active reference on @ioc. The caller must already have an + * active reference on @ioc. + */ +static inline void get_io_context_active(struct io_context *ioc) { - /* - * if ref count is zero, don't allow sharing (ioc is going away, it's - * a race). - */ - if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) { - atomic_inc(&ioc->nr_tasks); - return ioc; - } + WARN_ON_ONCE(atomic_long_read(&ioc->refcount) <= 0); + WARN_ON_ONCE(atomic_read(&ioc->active_ref) <= 0); + atomic_long_inc(&ioc->refcount); + atomic_inc(&ioc->active_ref); +} + +static inline void ioc_task_link(struct io_context *ioc) +{ + get_io_context_active(ioc); - return NULL; + WARN_ON_ONCE(atomic_read(&ioc->nr_tasks) <= 0); + atomic_inc(&ioc->nr_tasks); } struct task_struct; #ifdef CONFIG_BLOCK void put_io_context(struct io_context *ioc); +void put_io_context_active(struct io_context *ioc); void exit_io_context(struct task_struct *task); struct io_context *get_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node); -void ioc_ioprio_changed(struct io_context *ioc, int ioprio); -void ioc_cgroup_changed(struct io_context *ioc); -unsigned int icq_get_changed(struct io_cq *icq); #else struct io_context; static inline void put_io_context(struct io_context *ioc) { } |