From f54d1867005c3323f5d8ad83eed823e84226c429 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 25 Oct 2016 13:00:45 +0100 Subject: dma-buf: Rename struct fence to dma_fence MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Gustavo Padovan Acked-by: Sumit Semwal Acked-by: Christian König Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20161025120045.28839-1-chris@chris-wilson.co.uk --- include/linux/dma-buf.h | 4 +- include/linux/dma-fence-array.h | 86 ++++++++ include/linux/dma-fence.h | 437 ++++++++++++++++++++++++++++++++++++++++ include/linux/fence-array.h | 84 -------- include/linux/fence.h | 424 -------------------------------------- include/linux/reservation.h | 28 +-- include/linux/seqno-fence.h | 20 +- include/linux/sync_file.h | 14 +- 8 files changed, 556 insertions(+), 541 deletions(-) create mode 100644 include/linux/dma-fence-array.h create mode 100644 include/linux/dma-fence.h delete mode 100644 include/linux/fence-array.h delete mode 100644 include/linux/fence.h (limited to 'include/linux') diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index e0b0741ae671..8daeb3ce0016 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -30,7 +30,7 @@ #include #include #include -#include +#include #include struct device; @@ -143,7 +143,7 @@ struct dma_buf { wait_queue_head_t poll; struct dma_buf_poll_cb_t { - struct fence_cb cb; + struct dma_fence_cb cb; wait_queue_head_t *poll; unsigned long active; diff --git a/include/linux/dma-fence-array.h b/include/linux/dma-fence-array.h new file mode 100644 index 000000000000..5900945f962d --- /dev/null +++ b/include/linux/dma-fence-array.h @@ -0,0 +1,86 @@ +/* + * fence-array: aggregates fence to be waited together + * + * Copyright (C) 2016 Collabora Ltd + * Copyright (C) 2016 Advanced Micro Devices, Inc. + * Authors: + * Gustavo Padovan + * Christian König + * + * 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_DMA_FENCE_ARRAY_H +#define __LINUX_DMA_FENCE_ARRAY_H + +#include + +/** + * struct dma_fence_array_cb - callback helper for fence array + * @cb: fence callback structure for signaling + * @array: reference to the parent fence array object + */ +struct dma_fence_array_cb { + struct dma_fence_cb cb; + struct dma_fence_array *array; +}; + +/** + * struct dma_fence_array - fence to represent an array of fences + * @base: fence base class + * @lock: spinlock for fence handling + * @num_fences: number of fences in the array + * @num_pending: fences in the array still pending + * @fences: array of the fences + */ +struct dma_fence_array { + struct dma_fence base; + + spinlock_t lock; + unsigned num_fences; + atomic_t num_pending; + struct dma_fence **fences; +}; + +extern const struct dma_fence_ops dma_fence_array_ops; + +/** + * dma_fence_is_array - check if a fence is from the array subsclass + * @fence: fence to test + * + * Return true if it is a dma_fence_array and false otherwise. + */ +static inline bool dma_fence_is_array(struct dma_fence *fence) +{ + return fence->ops == &dma_fence_array_ops; +} + +/** + * to_dma_fence_array - cast a fence to a dma_fence_array + * @fence: fence to cast to a dma_fence_array + * + * Returns NULL if the fence is not a dma_fence_array, + * or the dma_fence_array otherwise. + */ +static inline struct dma_fence_array * +to_dma_fence_array(struct dma_fence *fence) +{ + if (fence->ops != &dma_fence_array_ops) + return NULL; + + return container_of(fence, struct dma_fence_array, base); +} + +struct dma_fence_array *dma_fence_array_create(int num_fences, + struct dma_fence **fences, + u64 context, unsigned seqno, + bool signal_on_any); + +#endif /* __LINUX_DMA_FENCE_ARRAY_H */ diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h new file mode 100644 index 000000000000..ba60c043a5d3 --- /dev/null +++ b/include/linux/dma-fence.h @@ -0,0 +1,437 @@ +/* + * Fence mechanism for dma-buf to allow for asynchronous dma access + * + * Copyright (C) 2012 Canonical Ltd + * Copyright (C) 2012 Texas Instruments + * + * Authors: + * Rob Clark + * Maarten Lankhorst + * + * 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_DMA_FENCE_H +#define __LINUX_DMA_FENCE_H + +#include +#include +#include +#include +#include +#include +#include +#include + +struct dma_fence; +struct dma_fence_ops; +struct dma_fence_cb; + +/** + * struct dma_fence - software synchronization primitive + * @refcount: refcount for this fence + * @ops: dma_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 + * dma_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 DMA_FENCE_FLAG_* defined below + * @timestamp: Timestamp when the fence was signaled. + * @status: Optional, only valid if < 0, must be set before calling + * dma_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. + * + * DMA_FENCE_FLAG_SIGNALED_BIT - fence is already signaled + * DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT - enable_signaling might have been called + * DMA_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 dma_fence_signal was called right + * before this bit was set, it would have been able to set the + * DMA_FENCE_FLAG_SIGNALED_BIT, before enable_signaling was called. + * Adding a check for DMA_FENCE_FLAG_SIGNALED_BIT after setting + * DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT closes this race, and makes sure that + * after dma_fence_signal was called, any enable_signaling call will have either + * been completed, or never called at all. + */ +struct dma_fence { + struct kref refcount; + const struct dma_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 dma_fence_flag_bits { + DMA_FENCE_FLAG_SIGNALED_BIT, + DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, + DMA_FENCE_FLAG_USER_BITS, /* must always be last member */ +}; + +typedef void (*dma_fence_func_t)(struct dma_fence *fence, + struct dma_fence_cb *cb); + +/** + * struct dma_fence_cb - callback for dma_fence_add_callback + * @node: used by dma_fence_add_callback to append this struct to fence::cb_list + * @func: dma_fence_func_t to call + * + * This struct will be initialized by dma_fence_add_callback, additional + * data can be passed along by embedding dma_fence_cb in another struct. + */ +struct dma_fence_cb { + struct list_head node; + dma_fence_func_t func; +}; + +/** + * struct dma_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 dma_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 dma_fence_signal before enable_signaling is called allows + * for a tiny race window in which enable_signaling is called during, + * before, or after dma_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 dma_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 dma_fence_default_wait for default implementation. + * the dma_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 dma_fence_ops { + const char * (*get_driver_name)(struct dma_fence *fence); + const char * (*get_timeline_name)(struct dma_fence *fence); + bool (*enable_signaling)(struct dma_fence *fence); + bool (*signaled)(struct dma_fence *fence); + signed long (*wait)(struct dma_fence *fence, + bool intr, signed long timeout); + void (*release)(struct dma_fence *fence); + + int (*fill_driver_data)(struct dma_fence *fence, void *data, int size); + void (*fence_value_str)(struct dma_fence *fence, char *str, int size); + void (*timeline_value_str)(struct dma_fence *fence, + char *str, int size); +}; + +void dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops, + spinlock_t *lock, u64 context, unsigned seqno); + +void dma_fence_release(struct kref *kref); +void dma_fence_free(struct dma_fence *fence); + +/** + * dma_fence_put - decreases refcount of the fence + * @fence: [in] fence to reduce refcount of + */ +static inline void dma_fence_put(struct dma_fence *fence) +{ + if (fence) + kref_put(&fence->refcount, dma_fence_release); +} + +/** + * dma_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 dma_fence *dma_fence_get(struct dma_fence *fence) +{ + if (fence) + kref_get(&fence->refcount); + return fence; +} + +/** + * dma_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 dma_fence *dma_fence_get_rcu(struct dma_fence *fence) +{ + if (kref_get_unless_zero(&fence->refcount)) + return fence; + else + return NULL; +} + +/** + * dma_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 dma_fence * +dma_fence_get_rcu_safe(struct dma_fence * __rcu *fencep) +{ + do { + struct dma_fence *fence; + + fence = rcu_dereference(*fencep); + if (!fence || !dma_fence_get_rcu(fence)) + return NULL; + + /* The atomic_inc_not_zero() inside dma_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); + + dma_fence_put(fence); + } while (1); +} + +int dma_fence_signal(struct dma_fence *fence); +int dma_fence_signal_locked(struct dma_fence *fence); +signed long dma_fence_default_wait(struct dma_fence *fence, + bool intr, signed long timeout); +int dma_fence_add_callback(struct dma_fence *fence, + struct dma_fence_cb *cb, + dma_fence_func_t func); +bool dma_fence_remove_callback(struct dma_fence *fence, + struct dma_fence_cb *cb); +void dma_fence_enable_sw_signaling(struct dma_fence *fence); + +/** + * dma_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 dma_fence_add_callback, dma_fence_wait or + * dma_fence_enable_sw_signaling haven't been called before. + * + * This function requires fence->lock to be held. + */ +static inline bool +dma_fence_is_signaled_locked(struct dma_fence *fence) +{ + if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) + return true; + + if (fence->ops->signaled && fence->ops->signaled(fence)) { + dma_fence_signal_locked(fence); + return true; + } + + return false; +} + +/** + * dma_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 dma_fence_add_callback, dma_fence_wait or + * dma_fence_enable_sw_signaling haven't been called before. + * + * It's recommended for seqno fences to call dma_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 +dma_fence_is_signaled(struct dma_fence *fence) +{ + if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) + return true; + + if (fence->ops->signaled && fence->ops->signaled(fence)) { + dma_fence_signal(fence); + return true; + } + + return false; +} + +/** + * dma_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 dma_fence_is_later(struct dma_fence *f1, + struct dma_fence *f2) +{ + if (WARN_ON(f1->context != f2->context)) + return false; + + return (int)(f1->seqno - f2->seqno) > 0; +} + +/** + * dma_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 dma_fence *dma_fence_later(struct dma_fence *f1, + struct dma_fence *f2) +{ + if (WARN_ON(f1->context != f2->context)) + return NULL; + + /* + * Can't check just DMA_FENCE_FLAG_SIGNALED_BIT here, it may never + * have been set if enable_signaling wasn't called, and enabling that + * here is overkill. + */ + if (dma_fence_is_later(f1, f2)) + return dma_fence_is_signaled(f1) ? NULL : f1; + else + return dma_fence_is_signaled(f2) ? NULL : f2; +} + +signed long dma_fence_wait_timeout(struct dma_fence *, + bool intr, signed long timeout); +signed long dma_fence_wait_any_timeout(struct dma_fence **fences, + uint32_t count, + bool intr, signed long timeout); + +/** + * dma_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 dma_fence_wait(struct dma_fence *fence, bool intr) +{ + signed long ret; + + /* Since dma_fence_wait_timeout cannot timeout with + * MAX_SCHEDULE_TIMEOUT, only valid return values are + * -ERESTARTSYS and MAX_SCHEDULE_TIMEOUT. + */ + ret = dma_fence_wait_timeout(fence, intr, MAX_SCHEDULE_TIMEOUT); + + return ret < 0 ? ret : 0; +} + +u64 dma_fence_context_alloc(unsigned num); + +#define DMA_FENCE_TRACE(f, fmt, args...) \ + do { \ + struct dma_fence *__ff = (f); \ + if (IS_ENABLED(CONFIG_DMA_FENCE_TRACE)) \ + pr_info("f %llu#%u: " fmt, \ + __ff->context, __ff->seqno, ##args); \ + } while (0) + +#define DMA_FENCE_WARN(f, fmt, args...) \ + do { \ + struct dma_fence *__ff = (f); \ + pr_warn("f %llu#%u: " fmt, __ff->context, __ff->seqno, \ + ##args); \ + } while (0) + +#define DMA_FENCE_ERR(f, fmt, args...) \ + do { \ + struct dma_fence *__ff = (f); \ + pr_err("f %llu#%u: " fmt, __ff->context, __ff->seqno, \ + ##args); \ + } while (0) + +#endif /* __LINUX_DMA_FENCE_H */ diff --git a/include/linux/fence-array.h b/include/linux/fence-array.h deleted file mode 100644 index 9ea2bde10ac1..000000000000 --- a/include/linux/fence-array.h +++ /dev/null @@ -1,84 +0,0 @@ -/* - * fence-array: aggregates fence to be waited together - * - * Copyright (C) 2016 Collabora Ltd - * Copyright (C) 2016 Advanced Micro Devices, Inc. - * Authors: - * Gustavo Padovan - * Christian König - * - * 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_ARRAY_H -#define __LINUX_FENCE_ARRAY_H - -#include - -/** - * struct fence_array_cb - callback helper for fence array - * @cb: fence callback structure for signaling - * @array: reference to the parent fence array object - */ -struct fence_array_cb { - struct fence_cb cb; - struct fence_array *array; -}; - -/** - * struct fence_array - fence to represent an array of fences - * @base: fence base class - * @lock: spinlock for fence handling - * @num_fences: number of fences in the array - * @num_pending: fences in the array still pending - * @fences: array of the fences - */ -struct fence_array { - struct fence base; - - spinlock_t lock; - unsigned num_fences; - atomic_t num_pending; - struct fence **fences; -}; - -extern const struct fence_ops fence_array_ops; - -/** - * fence_is_array - check if a fence is from the array subsclass - * @fence: fence to test - * - * Return true if it is a fence_array and false otherwise. - */ -static inline bool fence_is_array(struct fence *fence) -{ - return fence->ops == &fence_array_ops; -} - -/** - * to_fence_array - cast a fence to a fence_array - * @fence: fence to cast to a fence_array - * - * Returns NULL if the fence is not a fence_array, - * or the fence_array otherwise. - */ -static inline struct fence_array *to_fence_array(struct fence *fence) -{ - if (fence->ops != &fence_array_ops) - return NULL; - - return container_of(fence, struct fence_array, base); -} - -struct fence_array *fence_array_create(int num_fences, struct fence **fences, - u64 context, unsigned seqno, - bool signal_on_any); - -#endif /* __LINUX_FENCE_ARRAY_H */ 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 - * Maarten Lankhorst - * - * 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 -#include -#include -#include -#include -#include -#include -#include - -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 */ diff --git a/include/linux/reservation.h b/include/linux/reservation.h index b0f305e77b7f..2e313cca08f0 100644 --- a/include/linux/reservation.h +++ b/include/linux/reservation.h @@ -40,7 +40,7 @@ #define _LINUX_RESERVATION_H #include -#include +#include #include #include #include @@ -59,7 +59,7 @@ extern const char reservation_seqcount_string[]; struct reservation_object_list { struct rcu_head rcu; u32 shared_count, shared_max; - struct fence __rcu *shared[]; + struct dma_fence __rcu *shared[]; }; /** @@ -74,7 +74,7 @@ struct reservation_object { struct ww_mutex lock; seqcount_t seq; - struct fence __rcu *fence_excl; + struct dma_fence __rcu *fence_excl; struct reservation_object_list __rcu *fence; struct reservation_object_list *staged; }; @@ -107,7 +107,7 @@ reservation_object_fini(struct reservation_object *obj) { int i; struct reservation_object_list *fobj; - struct fence *excl; + struct dma_fence *excl; /* * This object should be dead and all references must have @@ -115,12 +115,12 @@ reservation_object_fini(struct reservation_object *obj) */ excl = rcu_dereference_protected(obj->fence_excl, 1); if (excl) - fence_put(excl); + dma_fence_put(excl); fobj = rcu_dereference_protected(obj->fence, 1); if (fobj) { for (i = 0; i < fobj->shared_count; ++i) - fence_put(rcu_dereference_protected(fobj->shared[i], 1)); + dma_fence_put(rcu_dereference_protected(fobj->shared[i], 1)); kfree(fobj); } @@ -155,7 +155,7 @@ reservation_object_get_list(struct reservation_object *obj) * RETURNS * The exclusive fence or NULL */ -static inline struct fence * +static inline struct dma_fence * reservation_object_get_excl(struct reservation_object *obj) { return rcu_dereference_protected(obj->fence_excl, @@ -173,10 +173,10 @@ reservation_object_get_excl(struct reservation_object *obj) * RETURNS * The exclusive fence or NULL if none */ -static inline struct fence * +static inline struct dma_fence * reservation_object_get_excl_rcu(struct reservation_object *obj) { - struct fence *fence; + struct dma_fence *fence; unsigned seq; retry: seq = read_seqcount_begin(&obj->seq); @@ -186,22 +186,22 @@ retry: rcu_read_unlock(); goto retry; } - fence = fence_get(fence); + fence = dma_fence_get(fence); rcu_read_unlock(); return fence; } int reservation_object_reserve_shared(struct reservation_object *obj); void reservation_object_add_shared_fence(struct reservation_object *obj, - struct fence *fence); + struct dma_fence *fence); void reservation_object_add_excl_fence(struct reservation_object *obj, - struct fence *fence); + struct dma_fence *fence); int reservation_object_get_fences_rcu(struct reservation_object *obj, - struct fence **pfence_excl, + struct dma_fence **pfence_excl, unsigned *pshared_count, - struct fence ***pshared); + struct dma_fence ***pshared); long reservation_object_wait_timeout_rcu(struct reservation_object *obj, bool wait_all, bool intr, diff --git a/include/linux/seqno-fence.h b/include/linux/seqno-fence.h index a1ba6a5ccdd6..c58c535d12a8 100644 --- a/include/linux/seqno-fence.h +++ b/include/linux/seqno-fence.h @@ -20,7 +20,7 @@ #ifndef __LINUX_SEQNO_FENCE_H #define __LINUX_SEQNO_FENCE_H -#include +#include #include enum seqno_fence_condition { @@ -29,15 +29,15 @@ enum seqno_fence_condition { }; struct seqno_fence { - struct fence base; + struct dma_fence base; - const struct fence_ops *ops; + const struct dma_fence_ops *ops; struct dma_buf *sync_buf; uint32_t seqno_ofs; enum seqno_fence_condition condition; }; -extern const struct fence_ops seqno_fence_ops; +extern const struct dma_fence_ops seqno_fence_ops; /** * to_seqno_fence - cast a fence to a seqno_fence @@ -47,7 +47,7 @@ extern const struct fence_ops seqno_fence_ops; * or the seqno_fence otherwise. */ static inline struct seqno_fence * -to_seqno_fence(struct fence *fence) +to_seqno_fence(struct dma_fence *fence) { if (fence->ops != &seqno_fence_ops) return NULL; @@ -83,9 +83,9 @@ to_seqno_fence(struct fence *fence) * dma-buf for sync_buf, since mapping or unmapping the sync_buf to the * device's vm can be expensive. * - * It is recommended for creators of seqno_fence to call fence_signal + * It is recommended for creators of seqno_fence to call dma_fence_signal() * before destruction. This will prevent possible issues from wraparound at - * time of issue vs time of check, since users can check fence_is_signaled + * time of issue vs time of check, since users can check dma_fence_is_signaled() * before submitting instructions for the hardware to wait on the fence. * However, when ops.enable_signaling is not called, it doesn't have to be * done as soon as possible, just before there's any real danger of seqno @@ -96,18 +96,18 @@ seqno_fence_init(struct seqno_fence *fence, spinlock_t *lock, struct dma_buf *sync_buf, uint32_t context, uint32_t seqno_ofs, uint32_t seqno, enum seqno_fence_condition cond, - const struct fence_ops *ops) + const struct dma_fence_ops *ops) { BUG_ON(!fence || !sync_buf || !ops); BUG_ON(!ops->wait || !ops->enable_signaling || !ops->get_driver_name || !ops->get_timeline_name); /* - * ops is used in fence_init for get_driver_name, so needs to be + * ops is used in dma_fence_init for get_driver_name, so needs to be * initialized first */ fence->ops = ops; - fence_init(&fence->base, &seqno_fence_ops, lock, context, seqno); + dma_fence_init(&fence->base, &seqno_fence_ops, lock, context, seqno); get_dma_buf(sync_buf); fence->sync_buf = sync_buf; fence->seqno_ofs = seqno_ofs; diff --git a/include/linux/sync_file.h b/include/linux/sync_file.h index aa17ccfc2f57..3e3ab84fc4cd 100644 --- a/include/linux/sync_file.h +++ b/include/linux/sync_file.h @@ -18,8 +18,8 @@ #include #include #include -#include -#include +#include +#include /** * struct sync_file - sync file to export to the userspace @@ -41,13 +41,13 @@ struct sync_file { wait_queue_head_t wq; - struct fence *fence; - struct fence_cb cb; + struct dma_fence *fence; + struct dma_fence_cb cb; }; -#define POLL_ENABLED FENCE_FLAG_USER_BITS +#define POLL_ENABLED DMA_FENCE_FLAG_USER_BITS -struct sync_file *sync_file_create(struct fence *fence); -struct fence *sync_file_get_fence(int fd); +struct sync_file *sync_file_create(struct dma_fence *fence); +struct dma_fence *sync_file_get_fence(int fd); #endif /* _LINUX_SYNC_H */ -- cgit v1.2.3