summaryrefslogtreecommitdiff
path: root/include/linux/fence.h
diff options
context:
space:
mode:
authorChris Wilson <chris@chris-wilson.co.uk>2016-10-25 13:00:45 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2016-10-25 14:40:39 +0200
commitf54d1867005c3323f5d8ad83eed823e84226c429 (patch)
tree026c3f57bc546d3a0205389d0f8e0d02ce8a76ac /include/linux/fence.h
parent0fc4f78f44e6c6148cee32456f0d0023ec1c1fd8 (diff)
dma-buf: Rename struct fence to dma_fence
I plan to usurp the short name of struct fence for a core kernel struct, and so I need to rename the specialised fence/timeline for DMA operations to make room. A consensus was reached in https://lists.freedesktop.org/archives/dri-devel/2016-July/113083.html that making clear this fence applies to DMA operations was a good thing. Since then the patch has grown a bit as usage increases, so hopefully it remains a good thing! (v2...: rebase, rerun spatch) v3: Compile on msm, spotted a manual fixup that I broke. v4: Try again for msm, sorry Daniel coccinelle script: @@ @@ - struct fence + struct dma_fence @@ @@ - struct fence_ops + struct dma_fence_ops @@ @@ - struct fence_cb + struct dma_fence_cb @@ @@ - struct fence_array + struct dma_fence_array @@ @@ - enum fence_flag_bits + enum dma_fence_flag_bits @@ @@ ( - fence_init + dma_fence_init | - fence_release + dma_fence_release | - fence_free + dma_fence_free | - fence_get + dma_fence_get | - fence_get_rcu + dma_fence_get_rcu | - fence_put + dma_fence_put | - fence_signal + dma_fence_signal | - fence_signal_locked + dma_fence_signal_locked | - fence_default_wait + dma_fence_default_wait | - fence_add_callback + dma_fence_add_callback | - fence_remove_callback + dma_fence_remove_callback | - fence_enable_sw_signaling + dma_fence_enable_sw_signaling | - fence_is_signaled_locked + dma_fence_is_signaled_locked | - fence_is_signaled + dma_fence_is_signaled | - fence_is_later + dma_fence_is_later | - fence_later + dma_fence_later | - fence_wait_timeout + dma_fence_wait_timeout | - fence_wait_any_timeout + dma_fence_wait_any_timeout | - fence_wait + dma_fence_wait | - fence_context_alloc + dma_fence_context_alloc | - fence_array_create + dma_fence_array_create | - to_fence_array + to_dma_fence_array | - fence_is_array + dma_fence_is_array | - trace_fence_emit + trace_dma_fence_emit | - FENCE_TRACE + DMA_FENCE_TRACE | - FENCE_WARN + DMA_FENCE_WARN | - FENCE_ERR + DMA_FENCE_ERR ) ( ... ) Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Christian K├Ânig <christian.koenig@amd.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/20161025120045.28839-1-chris@chris-wilson.co.uk
Diffstat (limited to 'include/linux/fence.h')
-rw-r--r--include/linux/fence.h424
1 files changed, 0 insertions, 424 deletions
diff --git a/include/linux/fence.h b/include/linux/fence.h
deleted file mode 100644
index c9c5ba98c302..000000000000
--- a/include/linux/fence.h
+++ /dev/null
@@ -1,424 +0,0 @@
-/*
- * Fence mechanism for dma-buf to allow for asynchronous dma access
- *
- * Copyright (C) 2012 Canonical Ltd
- * Copyright (C) 2012 Texas Instruments
- *
- * Authors:
- * Rob Clark <robdclark@gmail.com>
- * Maarten Lankhorst <maarten.lankhorst@canonical.com>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- */
-
-#ifndef __LINUX_FENCE_H
-#define __LINUX_FENCE_H
-
-#include <linux/err.h>
-#include <linux/wait.h>
-#include <linux/list.h>
-#include <linux/bitops.h>
-#include <linux/kref.h>
-#include <linux/sched.h>
-#include <linux/printk.h>
-#include <linux/rcupdate.h>
-
-struct fence;
-struct fence_ops;
-struct fence_cb;
-
-/**
- * struct fence - software synchronization primitive
- * @refcount: refcount for this fence
- * @ops: fence_ops associated with this fence
- * @rcu: used for releasing fence with kfree_rcu
- * @cb_list: list of all callbacks to call
- * @lock: spin_lock_irqsave used for locking
- * @context: execution context this fence belongs to, returned by
- * fence_context_alloc()
- * @seqno: the sequence number of this fence inside the execution context,
- * can be compared to decide which fence would be signaled later.
- * @flags: A mask of FENCE_FLAG_* defined below
- * @timestamp: Timestamp when the fence was signaled.
- * @status: Optional, only valid if < 0, must be set before calling
- * fence_signal, indicates that the fence has completed with an error.
- *
- * the flags member must be manipulated and read using the appropriate
- * atomic ops (bit_*), so taking the spinlock will not be needed most
- * of the time.
- *
- * FENCE_FLAG_SIGNALED_BIT - fence is already signaled
- * FENCE_FLAG_ENABLE_SIGNAL_BIT - enable_signaling might have been called*
- * FENCE_FLAG_USER_BITS - start of the unused bits, can be used by the
- * implementer of the fence for its own purposes. Can be used in different
- * ways by different fence implementers, so do not rely on this.
- *
- * Since atomic bitops are used, this is not guaranteed to be the case.
- * Particularly, if the bit was set, but fence_signal was called right
- * before this bit was set, it would have been able to set the
- * FENCE_FLAG_SIGNALED_BIT, before enable_signaling was called.
- * Adding a check for FENCE_FLAG_SIGNALED_BIT after setting
- * FENCE_FLAG_ENABLE_SIGNAL_BIT closes this race, and makes sure that
- * after fence_signal was called, any enable_signaling call will have either
- * been completed, or never called at all.
- */
-struct fence {
- struct kref refcount;
- const struct fence_ops *ops;
- struct rcu_head rcu;
- struct list_head cb_list;
- spinlock_t *lock;
- u64 context;
- unsigned seqno;
- unsigned long flags;
- ktime_t timestamp;
- int status;
-};
-
-enum fence_flag_bits {
- FENCE_FLAG_SIGNALED_BIT,
- FENCE_FLAG_ENABLE_SIGNAL_BIT,
- FENCE_FLAG_USER_BITS, /* must always be last member */
-};
-
-typedef void (*fence_func_t)(struct fence *fence, struct fence_cb *cb);
-
-/**
- * struct fence_cb - callback for fence_add_callback
- * @node: used by fence_add_callback to append this struct to fence::cb_list
- * @func: fence_func_t to call
- *
- * This struct will be initialized by fence_add_callback, additional
- * data can be passed along by embedding fence_cb in another struct.
- */
-struct fence_cb {
- struct list_head node;
- fence_func_t func;
-};
-
-/**
- * struct fence_ops - operations implemented for fence
- * @get_driver_name: returns the driver name.
- * @get_timeline_name: return the name of the context this fence belongs to.
- * @enable_signaling: enable software signaling of fence.
- * @signaled: [optional] peek whether the fence is signaled, can be null.
- * @wait: custom wait implementation, or fence_default_wait.
- * @release: [optional] called on destruction of fence, can be null
- * @fill_driver_data: [optional] callback to fill in free-form debug info
- * Returns amount of bytes filled, or -errno.
- * @fence_value_str: [optional] fills in the value of the fence as a string
- * @timeline_value_str: [optional] fills in the current value of the timeline
- * as a string
- *
- * Notes on enable_signaling:
- * For fence implementations that have the capability for hw->hw
- * signaling, they can implement this op to enable the necessary
- * irqs, or insert commands into cmdstream, etc. This is called
- * in the first wait() or add_callback() path to let the fence
- * implementation know that there is another driver waiting on
- * the signal (ie. hw->sw case).
- *
- * This function can be called called from atomic context, but not
- * from irq context, so normal spinlocks can be used.
- *
- * A return value of false indicates the fence already passed,
- * or some failure occurred that made it impossible to enable
- * signaling. True indicates successful enabling.
- *
- * fence->status may be set in enable_signaling, but only when false is
- * returned.
- *
- * Calling fence_signal before enable_signaling is called allows
- * for a tiny race window in which enable_signaling is called during,
- * before, or after fence_signal. To fight this, it is recommended
- * that before enable_signaling returns true an extra reference is
- * taken on the fence, to be released when the fence is signaled.
- * This will mean fence_signal will still be called twice, but
- * the second time will be a noop since it was already signaled.
- *
- * Notes on signaled:
- * May set fence->status if returning true.
- *
- * Notes on wait:
- * Must not be NULL, set to fence_default_wait for default implementation.
- * the fence_default_wait implementation should work for any fence, as long
- * as enable_signaling works correctly.
- *
- * Must return -ERESTARTSYS if the wait is intr = true and the wait was
- * interrupted, and remaining jiffies if fence has signaled, or 0 if wait
- * timed out. Can also return other error values on custom implementations,
- * which should be treated as if the fence is signaled. For example a hardware
- * lockup could be reported like that.
- *
- * Notes on release:
- * Can be NULL, this function allows additional commands to run on
- * destruction of the fence. Can be called from irq context.
- * If pointer is set to NULL, kfree will get called instead.
- */
-
-struct fence_ops {
- const char * (*get_driver_name)(struct fence *fence);
- const char * (*get_timeline_name)(struct fence *fence);
- bool (*enable_signaling)(struct fence *fence);
- bool (*signaled)(struct fence *fence);
- signed long (*wait)(struct fence *fence, bool intr, signed long timeout);
- void (*release)(struct fence *fence);
-
- int (*fill_driver_data)(struct fence *fence, void *data, int size);
- void (*fence_value_str)(struct fence *fence, char *str, int size);
- void (*timeline_value_str)(struct fence *fence, char *str, int size);
-};
-
-void fence_init(struct fence *fence, const struct fence_ops *ops,
- spinlock_t *lock, u64 context, unsigned seqno);
-
-void fence_release(struct kref *kref);
-void fence_free(struct fence *fence);
-
-/**
- * fence_put - decreases refcount of the fence
- * @fence: [in] fence to reduce refcount of
- */
-static inline void fence_put(struct fence *fence)
-{
- if (fence)
- kref_put(&fence->refcount, fence_release);
-}
-
-/**
- * fence_get - increases refcount of the fence
- * @fence: [in] fence to increase refcount of
- *
- * Returns the same fence, with refcount increased by 1.
- */
-static inline struct fence *fence_get(struct fence *fence)
-{
- if (fence)
- kref_get(&fence->refcount);
- return fence;
-}
-
-/**
- * fence_get_rcu - get a fence from a reservation_object_list with rcu read lock
- * @fence: [in] fence to increase refcount of
- *
- * Function returns NULL if no refcount could be obtained, or the fence.
- */
-static inline struct fence *fence_get_rcu(struct fence *fence)
-{
- if (kref_get_unless_zero(&fence->refcount))
- return fence;
- else
- return NULL;
-}
-
-/**
- * fence_get_rcu_safe - acquire a reference to an RCU tracked fence
- * @fence: [in] pointer to fence to increase refcount of
- *
- * Function returns NULL if no refcount could be obtained, or the fence.
- * This function handles acquiring a reference to a fence that may be
- * reallocated within the RCU grace period (such as with SLAB_DESTROY_BY_RCU),
- * so long as the caller is using RCU on the pointer to the fence.
- *
- * An alternative mechanism is to employ a seqlock to protect a bunch of
- * fences, such as used by struct reservation_object. When using a seqlock,
- * the seqlock must be taken before and checked after a reference to the
- * fence is acquired (as shown here).
- *
- * The caller is required to hold the RCU read lock.
- */
-static inline struct fence *fence_get_rcu_safe(struct fence * __rcu *fencep)
-{
- do {
- struct fence *fence;
-
- fence = rcu_dereference(*fencep);
- if (!fence || !fence_get_rcu(fence))
- return NULL;
-
- /* The atomic_inc_not_zero() inside fence_get_rcu()
- * provides a full memory barrier upon success (such as now).
- * This is paired with the write barrier from assigning
- * to the __rcu protected fence pointer so that if that
- * pointer still matches the current fence, we know we
- * have successfully acquire a reference to it. If it no
- * longer matches, we are holding a reference to some other
- * reallocated pointer. This is possible if the allocator
- * is using a freelist like SLAB_DESTROY_BY_RCU where the
- * fence remains valid for the RCU grace period, but it
- * may be reallocated. When using such allocators, we are
- * responsible for ensuring the reference we get is to
- * the right fence, as below.
- */
- if (fence == rcu_access_pointer(*fencep))
- return rcu_pointer_handoff(fence);
-
- fence_put(fence);
- } while (1);
-}
-
-int fence_signal(struct fence *fence);
-int fence_signal_locked(struct fence *fence);
-signed long fence_default_wait(struct fence *fence, bool intr, signed long timeout);
-int fence_add_callback(struct fence *fence, struct fence_cb *cb,
- fence_func_t func);
-bool fence_remove_callback(struct fence *fence, struct fence_cb *cb);
-void fence_enable_sw_signaling(struct fence *fence);
-
-/**
- * fence_is_signaled_locked - Return an indication if the fence is signaled yet.
- * @fence: [in] the fence to check
- *
- * Returns true if the fence was already signaled, false if not. Since this
- * function doesn't enable signaling, it is not guaranteed to ever return
- * true if fence_add_callback, fence_wait or fence_enable_sw_signaling
- * haven't been called before.
- *
- * This function requires fence->lock to be held.
- */
-static inline bool
-fence_is_signaled_locked(struct fence *fence)
-{
- if (test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags))
- return true;
-
- if (fence->ops->signaled && fence->ops->signaled(fence)) {
- fence_signal_locked(fence);
- return true;
- }
-
- return false;
-}
-
-/**
- * fence_is_signaled - Return an indication if the fence is signaled yet.
- * @fence: [in] the fence to check
- *
- * Returns true if the fence was already signaled, false if not. Since this
- * function doesn't enable signaling, it is not guaranteed to ever return
- * true if fence_add_callback, fence_wait or fence_enable_sw_signaling
- * haven't been called before.
- *
- * It's recommended for seqno fences to call fence_signal when the
- * operation is complete, it makes it possible to prevent issues from
- * wraparound between time of issue and time of use by checking the return
- * value of this function before calling hardware-specific wait instructions.
- */
-static inline bool
-fence_is_signaled(struct fence *fence)
-{
- if (test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags))
- return true;
-
- if (fence->ops->signaled && fence->ops->signaled(fence)) {
- fence_signal(fence);
- return true;
- }
-
- return false;
-}
-
-/**
- * fence_is_later - return if f1 is chronologically later than f2
- * @f1: [in] the first fence from the same context
- * @f2: [in] the second fence from the same context
- *
- * Returns true if f1 is chronologically later than f2. Both fences must be
- * from the same context, since a seqno is not re-used across contexts.
- */
-static inline bool fence_is_later(struct fence *f1, struct fence *f2)
-{
- if (WARN_ON(f1->context != f2->context))
- return false;
-
- return (int)(f1->seqno - f2->seqno) > 0;
-}
-
-/**
- * fence_later - return the chronologically later fence
- * @f1: [in] the first fence from the same context
- * @f2: [in] the second fence from the same context
- *
- * Returns NULL if both fences are signaled, otherwise the fence that would be
- * signaled last. Both fences must be from the same context, since a seqno is
- * not re-used across contexts.
- */
-static inline struct fence *fence_later(struct fence *f1, struct fence *f2)
-{
- if (WARN_ON(f1->context != f2->context))
- return NULL;
-
- /*
- * can't check just FENCE_FLAG_SIGNALED_BIT here, it may never have been
- * set if enable_signaling wasn't called, and enabling that here is
- * overkill.
- */
- if (fence_is_later(f1, f2))
- return fence_is_signaled(f1) ? NULL : f1;
- else
- return fence_is_signaled(f2) ? NULL : f2;
-}
-
-signed long fence_wait_timeout(struct fence *, bool intr, signed long timeout);
-signed long fence_wait_any_timeout(struct fence **fences, uint32_t count,
- bool intr, signed long timeout);
-
-/**
- * fence_wait - sleep until the fence gets signaled
- * @fence: [in] the fence to wait on
- * @intr: [in] if true, do an interruptible wait
- *
- * This function will return -ERESTARTSYS if interrupted by a signal,
- * or 0 if the fence was signaled. Other error values may be
- * returned on custom implementations.
- *
- * Performs a synchronous wait on this fence. It is assumed the caller
- * directly or indirectly holds a reference to the fence, otherwise the
- * fence might be freed before return, resulting in undefined behavior.
- */
-static inline signed long fence_wait(struct fence *fence, bool intr)
-{
- signed long ret;
-
- /* Since fence_wait_timeout cannot timeout with
- * MAX_SCHEDULE_TIMEOUT, only valid return values are
- * -ERESTARTSYS and MAX_SCHEDULE_TIMEOUT.
- */
- ret = fence_wait_timeout(fence, intr, MAX_SCHEDULE_TIMEOUT);
-
- return ret < 0 ? ret : 0;
-}
-
-u64 fence_context_alloc(unsigned num);
-
-#define FENCE_TRACE(f, fmt, args...) \
- do { \
- struct fence *__ff = (f); \
- if (IS_ENABLED(CONFIG_FENCE_TRACE)) \
- pr_info("f %llu#%u: " fmt, \
- __ff->context, __ff->seqno, ##args); \
- } while (0)
-
-#define FENCE_WARN(f, fmt, args...) \
- do { \
- struct fence *__ff = (f); \
- pr_warn("f %llu#%u: " fmt, __ff->context, __ff->seqno, \
- ##args); \
- } while (0)
-
-#define FENCE_ERR(f, fmt, args...) \
- do { \
- struct fence *__ff = (f); \
- pr_err("f %llu#%u: " fmt, __ff->context, __ff->seqno, \
- ##args); \
- } while (0)
-
-#endif /* __LINUX_FENCE_H */