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![Daniel Vetter](/assets/img/avatar_default.png)
Almost everyone uses dma_fence_default_wait. v2: Also remove the BUG_ON(!ops->wait) (Chris). Reviewed-by: Christian König <christian.koenig@amd.com> (v1) Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Gustavo Padovan <gustavo@padovan.org> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20180503142603.28513-5-daniel.vetter@ffwll.ch
423 lines
9.9 KiB
C
423 lines
9.9 KiB
C
/*
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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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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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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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if (!list_empty(&pt->link)) {
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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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}
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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);
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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, "%d", 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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dma_fence_put(&pt->base);
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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 = sw_sync_ioctl,
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};
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