diff options
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) { } |