reservation: add headerdoc comments
Signed-off-by: Rob Clark <robdclark@gmail.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>hifive-unleashed-5.1
Rob Clark
Sumit Semwal
parent
e2082e3ab8
commit
dad6c3945f
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@ -35,6 +35,17 @@
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#include <linux/reservation.h>
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#include <linux/export.h>
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/**
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* DOC: Reservation Object Overview
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*
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* The reservation object provides a mechanism to manage shared and
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* exclusive fences associated with a buffer. A reservation object
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* can have attached one exclusive fence (normally associated with
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* write operations) or N shared fences (read operations). The RCU
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* mechanism is used to protect read access to fences from locked
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* write-side updates.
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*/
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DEFINE_WW_CLASS(reservation_ww_class);
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EXPORT_SYMBOL(reservation_ww_class);
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@ -43,9 +54,17 @@ EXPORT_SYMBOL(reservation_seqcount_class);
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const char reservation_seqcount_string[] = "reservation_seqcount";
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EXPORT_SYMBOL(reservation_seqcount_string);
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/*
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* Reserve space to add a shared fence to a reservation_object,
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* must be called with obj->lock held.
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/**
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* reservation_object_reserve_shared - Reserve space to add a shared
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* fence to a reservation_object.
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* @obj: reservation object
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*
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* Should be called before reservation_object_add_shared_fence(). Must
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* be called with obj->lock held.
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*
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* RETURNS
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* Zero for success, or -errno
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*/
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int reservation_object_reserve_shared(struct reservation_object *obj)
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{
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@ -180,7 +199,11 @@ done:
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fence_put(old_fence);
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}
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/*
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/**
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* reservation_object_add_shared_fence - Add a fence to a shared slot
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* @obj: the reservation object
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* @fence: the shared fence to add
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*
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* Add a fence to a shared slot, obj->lock must be held, and
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* reservation_object_reserve_shared_fence has been called.
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*/
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@ -200,6 +223,13 @@ void reservation_object_add_shared_fence(struct reservation_object *obj,
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}
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EXPORT_SYMBOL(reservation_object_add_shared_fence);
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/**
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* reservation_object_add_excl_fence - Add an exclusive fence.
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* @obj: the reservation object
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* @fence: the shared fence to add
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*
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* Add a fence to the exclusive slot. The obj->lock must be held.
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*/
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void reservation_object_add_excl_fence(struct reservation_object *obj,
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struct fence *fence)
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{
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@ -233,6 +263,18 @@ void reservation_object_add_excl_fence(struct reservation_object *obj,
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}
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EXPORT_SYMBOL(reservation_object_add_excl_fence);
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/**
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* reservation_object_get_fences_rcu - Get an object's shared and exclusive
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* fences without update side lock held
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* @obj: the reservation object
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* @pfence_excl: the returned exclusive fence (or NULL)
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* @pshared_count: the number of shared fences returned
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* @pshared: the array of shared fence ptrs returned (array is krealloc'd to
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* the required size, and must be freed by caller)
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*
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* RETURNS
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* Zero or -errno
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*/
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int reservation_object_get_fences_rcu(struct reservation_object *obj,
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struct fence **pfence_excl,
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unsigned *pshared_count,
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@ -319,6 +361,18 @@ unlock:
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}
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EXPORT_SYMBOL_GPL(reservation_object_get_fences_rcu);
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/**
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* reservation_object_wait_timeout_rcu - Wait on reservation's objects
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* shared and/or exclusive fences.
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* @obj: the reservation object
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* @wait_all: if true, wait on all fences, else wait on just exclusive fence
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* @intr: if true, do interruptible wait
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* @timeout: timeout value in jiffies or zero to return immediately
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*
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* RETURNS
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* Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
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* greater than zer on success.
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*/
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long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
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bool wait_all, bool intr,
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unsigned long timeout)
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@ -416,6 +470,16 @@ reservation_object_test_signaled_single(struct fence *passed_fence)
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return ret;
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}
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/**
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* reservation_object_test_signaled_rcu - Test if a reservation object's
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* fences have been signaled.
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* @obj: the reservation object
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* @test_all: if true, test all fences, otherwise only test the exclusive
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* fence
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*
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* RETURNS
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* true if all fences signaled, else false
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*/
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bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
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bool test_all)
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{
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@ -49,12 +49,27 @@ extern struct ww_class reservation_ww_class;
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extern struct lock_class_key reservation_seqcount_class;
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extern const char reservation_seqcount_string[];
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/**
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* struct reservation_object_list - a list of shared fences
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* @rcu: for internal use
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* @shared_count: table of shared fences
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* @shared_max: for growing shared fence table
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* @shared: shared fence table
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*/
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struct reservation_object_list {
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struct rcu_head rcu;
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u32 shared_count, shared_max;
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struct fence __rcu *shared[];
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};
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/**
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* struct reservation_object - a reservation object manages fences for a buffer
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* @lock: update side lock
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* @seq: sequence count for managing RCU read-side synchronization
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* @fence_excl: the exclusive fence, if there is one currently
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* @fence: list of current shared fences
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* @staged: staged copy of shared fences for RCU updates
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*/
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struct reservation_object {
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struct ww_mutex lock;
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seqcount_t seq;
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@ -68,6 +83,10 @@ struct reservation_object {
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#define reservation_object_assert_held(obj) \
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lockdep_assert_held(&(obj)->lock.base)
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/**
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* reservation_object_init - initialize a reservation object
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* @obj: the reservation object
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*/
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static inline void
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reservation_object_init(struct reservation_object *obj)
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{
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@ -79,6 +98,10 @@ reservation_object_init(struct reservation_object *obj)
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obj->staged = NULL;
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}
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/**
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* reservation_object_fini - destroys a reservation object
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* @obj: the reservation object
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*/
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static inline void
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reservation_object_fini(struct reservation_object *obj)
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{
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@ -106,6 +129,14 @@ reservation_object_fini(struct reservation_object *obj)
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ww_mutex_destroy(&obj->lock);
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}
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/**
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* reservation_object_get_list - get the reservation object's
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* shared fence list, with update-side lock held
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* @obj: the reservation object
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*
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* Returns the shared fence list. Does NOT take references to
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* the fence. The obj->lock must be held.
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*/
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static inline struct reservation_object_list *
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reservation_object_get_list(struct reservation_object *obj)
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{
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@ -113,6 +144,17 @@ reservation_object_get_list(struct reservation_object *obj)
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reservation_object_held(obj));
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}
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/**
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* reservation_object_get_excl - get the reservation object's
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* exclusive fence, with update-side lock held
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* @obj: the reservation object
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*
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* Returns the exclusive fence (if any). Does NOT take a
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* reference. The obj->lock must be held.
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*
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* RETURNS
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* The exclusive fence or NULL
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*/
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static inline struct fence *
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reservation_object_get_excl(struct reservation_object *obj)
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{
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@ -120,6 +162,17 @@ reservation_object_get_excl(struct reservation_object *obj)
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reservation_object_held(obj));
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}
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/**
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* reservation_object_get_excl_rcu - get the reservation object's
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* exclusive fence, without lock held.
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* @obj: the reservation object
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*
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* If there is an exclusive fence, this atomically increments it's
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* reference count and returns it.
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*
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* RETURNS
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* The exclusive fence or NULL if none
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*/
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static inline struct fence *
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reservation_object_get_excl_rcu(struct reservation_object *obj)
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{
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