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412 lines
9.5 KiB
412 lines
9.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Sync File validation framework |
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* |
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* Copyright (C) 2012 Google, Inc. |
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*/ |
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#include <linux/file.h> |
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#include <linux/fs.h> |
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#include <linux/uaccess.h> |
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#include <linux/slab.h> |
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#include <linux/sync_file.h> |
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#include "sync_debug.h" |
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#define CREATE_TRACE_POINTS |
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#include "sync_trace.h" |
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/* |
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* SW SYNC validation framework |
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* |
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* A sync object driver that uses a 32bit counter to coordinate |
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* synchronization. Useful when there is no hardware primitive backing |
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* the synchronization. |
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* |
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* To start the framework just open: |
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* |
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* <debugfs>/sync/sw_sync |
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* |
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* That will create a sync timeline, all fences created under this timeline |
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* file descriptor will belong to the this timeline. |
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* |
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* The 'sw_sync' file can be opened many times as to create different |
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* timelines. |
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* |
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* Fences can be created with SW_SYNC_IOC_CREATE_FENCE ioctl with struct |
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* sw_sync_create_fence_data as parameter. |
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* |
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* To increment the timeline counter, SW_SYNC_IOC_INC ioctl should be used |
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* with the increment as u32. This will update the last signaled value |
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* from the timeline and signal any fence that has a seqno smaller or equal |
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* to it. |
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* |
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* struct sw_sync_create_fence_data |
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* @value: the seqno to initialise the fence with |
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* @name: the name of the new sync point |
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* @fence: return the fd of the new sync_file with the created fence |
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*/ |
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struct sw_sync_create_fence_data { |
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__u32 value; |
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char name[32]; |
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__s32 fence; /* fd of new fence */ |
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}; |
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#define SW_SYNC_IOC_MAGIC 'W' |
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#define SW_SYNC_IOC_CREATE_FENCE _IOWR(SW_SYNC_IOC_MAGIC, 0,\ |
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struct sw_sync_create_fence_data) |
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#define SW_SYNC_IOC_INC _IOW(SW_SYNC_IOC_MAGIC, 1, __u32) |
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static const struct dma_fence_ops timeline_fence_ops; |
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static inline struct sync_pt *dma_fence_to_sync_pt(struct dma_fence *fence) |
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{ |
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if (fence->ops != &timeline_fence_ops) |
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return NULL; |
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return container_of(fence, struct sync_pt, base); |
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} |
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/** |
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* sync_timeline_create() - creates a sync object |
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* @name: sync_timeline name |
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* |
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* Creates a new sync_timeline. Returns the sync_timeline object or NULL in |
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* case of error. |
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*/ |
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static struct sync_timeline *sync_timeline_create(const char *name) |
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{ |
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struct sync_timeline *obj; |
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obj = kzalloc(sizeof(*obj), GFP_KERNEL); |
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if (!obj) |
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return NULL; |
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kref_init(&obj->kref); |
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obj->context = dma_fence_context_alloc(1); |
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strlcpy(obj->name, name, sizeof(obj->name)); |
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obj->pt_tree = RB_ROOT; |
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INIT_LIST_HEAD(&obj->pt_list); |
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spin_lock_init(&obj->lock); |
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sync_timeline_debug_add(obj); |
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return obj; |
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} |
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static void sync_timeline_free(struct kref *kref) |
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{ |
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struct sync_timeline *obj = |
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container_of(kref, struct sync_timeline, kref); |
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sync_timeline_debug_remove(obj); |
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kfree(obj); |
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} |
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static void sync_timeline_get(struct sync_timeline *obj) |
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{ |
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kref_get(&obj->kref); |
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} |
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static void sync_timeline_put(struct sync_timeline *obj) |
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{ |
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kref_put(&obj->kref, sync_timeline_free); |
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} |
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static const char *timeline_fence_get_driver_name(struct dma_fence *fence) |
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{ |
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return "sw_sync"; |
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} |
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static const char *timeline_fence_get_timeline_name(struct dma_fence *fence) |
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{ |
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struct sync_timeline *parent = dma_fence_parent(fence); |
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return parent->name; |
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} |
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static void timeline_fence_release(struct dma_fence *fence) |
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{ |
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struct sync_pt *pt = dma_fence_to_sync_pt(fence); |
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struct sync_timeline *parent = dma_fence_parent(fence); |
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unsigned long flags; |
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spin_lock_irqsave(fence->lock, flags); |
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if (!list_empty(&pt->link)) { |
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list_del(&pt->link); |
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rb_erase(&pt->node, &parent->pt_tree); |
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} |
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spin_unlock_irqrestore(fence->lock, flags); |
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sync_timeline_put(parent); |
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dma_fence_free(fence); |
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} |
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static bool timeline_fence_signaled(struct dma_fence *fence) |
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{ |
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struct sync_timeline *parent = dma_fence_parent(fence); |
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return !__dma_fence_is_later(fence->seqno, parent->value, fence->ops); |
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} |
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static bool timeline_fence_enable_signaling(struct dma_fence *fence) |
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{ |
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return true; |
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} |
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static void timeline_fence_value_str(struct dma_fence *fence, |
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char *str, int size) |
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{ |
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snprintf(str, size, "%lld", fence->seqno); |
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} |
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static void timeline_fence_timeline_value_str(struct dma_fence *fence, |
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char *str, int size) |
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{ |
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struct sync_timeline *parent = dma_fence_parent(fence); |
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snprintf(str, size, "%d", parent->value); |
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} |
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static const struct dma_fence_ops timeline_fence_ops = { |
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.get_driver_name = timeline_fence_get_driver_name, |
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.get_timeline_name = timeline_fence_get_timeline_name, |
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.enable_signaling = timeline_fence_enable_signaling, |
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.signaled = timeline_fence_signaled, |
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.release = timeline_fence_release, |
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.fence_value_str = timeline_fence_value_str, |
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.timeline_value_str = timeline_fence_timeline_value_str, |
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}; |
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/** |
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* sync_timeline_signal() - signal a status change on a sync_timeline |
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* @obj: sync_timeline to signal |
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* @inc: num to increment on timeline->value |
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* |
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* A sync implementation should call this any time one of it's fences |
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* has signaled or has an error condition. |
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*/ |
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static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc) |
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{ |
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struct sync_pt *pt, *next; |
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trace_sync_timeline(obj); |
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spin_lock_irq(&obj->lock); |
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obj->value += inc; |
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list_for_each_entry_safe(pt, next, &obj->pt_list, link) { |
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if (!timeline_fence_signaled(&pt->base)) |
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break; |
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list_del_init(&pt->link); |
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rb_erase(&pt->node, &obj->pt_tree); |
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/* |
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* A signal callback may release the last reference to this |
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* fence, causing it to be freed. That operation has to be |
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* last to avoid a use after free inside this loop, and must |
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* be after we remove the fence from the timeline in order to |
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* prevent deadlocking on timeline->lock inside |
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* timeline_fence_release(). |
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*/ |
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dma_fence_signal_locked(&pt->base); |
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} |
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spin_unlock_irq(&obj->lock); |
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} |
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/** |
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* sync_pt_create() - creates a sync pt |
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* @obj: parent sync_timeline |
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* @value: value of the fence |
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* |
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* Creates a new sync_pt (fence) as a child of @parent. @size bytes will be |
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* allocated allowing for implementation specific data to be kept after |
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* the generic sync_timeline struct. Returns the sync_pt object or |
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* NULL in case of error. |
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*/ |
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static struct sync_pt *sync_pt_create(struct sync_timeline *obj, |
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unsigned int value) |
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{ |
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struct sync_pt *pt; |
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pt = kzalloc(sizeof(*pt), GFP_KERNEL); |
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if (!pt) |
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return NULL; |
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sync_timeline_get(obj); |
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dma_fence_init(&pt->base, &timeline_fence_ops, &obj->lock, |
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obj->context, value); |
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INIT_LIST_HEAD(&pt->link); |
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spin_lock_irq(&obj->lock); |
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if (!dma_fence_is_signaled_locked(&pt->base)) { |
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struct rb_node **p = &obj->pt_tree.rb_node; |
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struct rb_node *parent = NULL; |
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while (*p) { |
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struct sync_pt *other; |
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int cmp; |
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parent = *p; |
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other = rb_entry(parent, typeof(*pt), node); |
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cmp = value - other->base.seqno; |
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if (cmp > 0) { |
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p = &parent->rb_right; |
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} else if (cmp < 0) { |
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p = &parent->rb_left; |
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} else { |
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if (dma_fence_get_rcu(&other->base)) { |
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sync_timeline_put(obj); |
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kfree(pt); |
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pt = other; |
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goto unlock; |
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} |
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p = &parent->rb_left; |
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} |
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} |
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rb_link_node(&pt->node, parent, p); |
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rb_insert_color(&pt->node, &obj->pt_tree); |
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parent = rb_next(&pt->node); |
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list_add_tail(&pt->link, |
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parent ? &rb_entry(parent, typeof(*pt), node)->link : &obj->pt_list); |
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} |
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unlock: |
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spin_unlock_irq(&obj->lock); |
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return pt; |
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} |
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/* |
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* *WARNING* |
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* |
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* improper use of this can result in deadlocking kernel drivers from userspace. |
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*/ |
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/* opening sw_sync create a new sync obj */ |
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static int sw_sync_debugfs_open(struct inode *inode, struct file *file) |
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{ |
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struct sync_timeline *obj; |
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char task_comm[TASK_COMM_LEN]; |
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get_task_comm(task_comm, current); |
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obj = sync_timeline_create(task_comm); |
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if (!obj) |
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return -ENOMEM; |
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file->private_data = obj; |
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return 0; |
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} |
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static int sw_sync_debugfs_release(struct inode *inode, struct file *file) |
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{ |
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struct sync_timeline *obj = file->private_data; |
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struct sync_pt *pt, *next; |
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spin_lock_irq(&obj->lock); |
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list_for_each_entry_safe(pt, next, &obj->pt_list, link) { |
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dma_fence_set_error(&pt->base, -ENOENT); |
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dma_fence_signal_locked(&pt->base); |
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} |
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spin_unlock_irq(&obj->lock); |
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sync_timeline_put(obj); |
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return 0; |
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} |
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static long sw_sync_ioctl_create_fence(struct sync_timeline *obj, |
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unsigned long arg) |
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{ |
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int fd = get_unused_fd_flags(O_CLOEXEC); |
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int err; |
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struct sync_pt *pt; |
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struct sync_file *sync_file; |
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struct sw_sync_create_fence_data data; |
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if (fd < 0) |
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return fd; |
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if (copy_from_user(&data, (void __user *)arg, sizeof(data))) { |
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err = -EFAULT; |
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goto err; |
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} |
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pt = sync_pt_create(obj, data.value); |
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if (!pt) { |
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err = -ENOMEM; |
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goto err; |
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} |
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sync_file = sync_file_create(&pt->base); |
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dma_fence_put(&pt->base); |
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if (!sync_file) { |
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err = -ENOMEM; |
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goto err; |
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} |
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data.fence = fd; |
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if (copy_to_user((void __user *)arg, &data, sizeof(data))) { |
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fput(sync_file->file); |
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err = -EFAULT; |
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goto err; |
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} |
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fd_install(fd, sync_file->file); |
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return 0; |
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err: |
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put_unused_fd(fd); |
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return err; |
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} |
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static long sw_sync_ioctl_inc(struct sync_timeline *obj, unsigned long arg) |
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{ |
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u32 value; |
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if (copy_from_user(&value, (void __user *)arg, sizeof(value))) |
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return -EFAULT; |
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while (value > INT_MAX) { |
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sync_timeline_signal(obj, INT_MAX); |
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value -= INT_MAX; |
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} |
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sync_timeline_signal(obj, value); |
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return 0; |
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} |
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static long sw_sync_ioctl(struct file *file, unsigned int cmd, |
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unsigned long arg) |
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{ |
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struct sync_timeline *obj = file->private_data; |
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switch (cmd) { |
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case SW_SYNC_IOC_CREATE_FENCE: |
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return sw_sync_ioctl_create_fence(obj, arg); |
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case SW_SYNC_IOC_INC: |
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return sw_sync_ioctl_inc(obj, arg); |
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default: |
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return -ENOTTY; |
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} |
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} |
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const struct file_operations sw_sync_debugfs_fops = { |
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.open = sw_sync_debugfs_open, |
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.release = sw_sync_debugfs_release, |
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.unlocked_ioctl = sw_sync_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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};
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