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From: Daniel Vetter <daniel@ffwll.ch>
To: "Christian König" <ckoenig.leichtzumerken@gmail.com>
Cc: sumit.semwal@linaro.org, gustavo@padovan.org, daniel@ffwll.ch,
	linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linaro-mm-sig@lists.linaro.org
Subject: Re: [PATCH 3/3] dma-buf: nuke SW_SYNC debugfs files
Date: Thu, 29 Jul 2021 09:23:55 +0200	[thread overview]
Message-ID: <YQJXi2JNZdH5DaR2@phenom.ffwll.local> (raw)
In-Reply-To: <20210729070330.41443-3-christian.koenig@amd.com>

On Thu, Jul 29, 2021 at 09:03:30AM +0200, Christian König wrote:
> As we now knew controlling dma_fence synchronization from userspace is
> extremely dangerous and can not only deadlock drivers but trivially also the
> whole kernel memory management.
> 
> Entirely remove this option. We now have in kernel unit tests to exercise the
> dma_fence framework and it's containers.
> 
> Signed-off-by: Christian König <christian.koenig@amd.com>

There's also igts for this, and Android heavily uses this. So I'm not sure
we can just nuke it.

I guess what we could do is maybe just taint the kernel if it's ever used?

Also for testing we use vgem now, which enforces a timeout.
-Daniel

> ---
>  drivers/dma-buf/Kconfig      |  13 --
>  drivers/dma-buf/Makefile     |   1 -
>  drivers/dma-buf/sw_sync.c    | 412 -----------------------------------
>  drivers/dma-buf/sync_debug.c | 190 ----------------
>  drivers/dma-buf/sync_debug.h |  72 ------
>  5 files changed, 688 deletions(-)
>  delete mode 100644 drivers/dma-buf/sw_sync.c
>  delete mode 100644 drivers/dma-buf/sync_debug.c
>  delete mode 100644 drivers/dma-buf/sync_debug.h
> 
> diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
> index 9561e3d2d428..26c53f45616a 100644
> --- a/drivers/dma-buf/Kconfig
> +++ b/drivers/dma-buf/Kconfig
> @@ -17,19 +17,6 @@ config SYNC_FILE
>  	  Files fds, to the DRM driver for example. More details at
>  	  Documentation/driver-api/sync_file.rst.
>  
> -config SW_SYNC
> -	bool "Sync File Validation Framework"
> -	default n
> -	depends on SYNC_FILE
> -	depends on DEBUG_FS
> -	help
> -	  A sync object driver that uses a 32bit counter to coordinate
> -	  synchronization.  Useful when there is no hardware primitive backing
> -	  the synchronization.
> -
> -	  WARNING: improper use of this can result in deadlocking kernel
> -	  drivers from userspace. Intended for test and debug only.
> -
>  config UDMABUF
>  	bool "userspace dmabuf misc driver"
>  	default n
> diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
> index 1ef021273a06..fa3af0953f87 100644
> --- a/drivers/dma-buf/Makefile
> +++ b/drivers/dma-buf/Makefile
> @@ -4,7 +4,6 @@ obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
>  obj-$(CONFIG_DMABUF_HEAPS)	+= dma-heap.o
>  obj-$(CONFIG_DMABUF_HEAPS)	+= heaps/
>  obj-$(CONFIG_SYNC_FILE)		+= sync_file.o
> -obj-$(CONFIG_SW_SYNC)		+= sw_sync.o sync_debug.o
>  obj-$(CONFIG_UDMABUF)		+= udmabuf.o
>  obj-$(CONFIG_DMABUF_SYSFS_STATS) += dma-buf-sysfs-stats.o
>  
> diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c
> deleted file mode 100644
> index 348b3a9170fa..000000000000
> --- a/drivers/dma-buf/sw_sync.c
> +++ /dev/null
> @@ -1,412 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/*
> - * Sync File validation framework
> - *
> - * Copyright (C) 2012 Google, Inc.
> - */
> -
> -#include <linux/file.h>
> -#include <linux/fs.h>
> -#include <linux/uaccess.h>
> -#include <linux/slab.h>
> -#include <linux/sync_file.h>
> -
> -#include "sync_debug.h"
> -
> -#define CREATE_TRACE_POINTS
> -#include "sync_trace.h"
> -
> -/*
> - * SW SYNC validation framework
> - *
> - * A sync object driver that uses a 32bit counter to coordinate
> - * synchronization.  Useful when there is no hardware primitive backing
> - * the synchronization.
> - *
> - * To start the framework just open:
> - *
> - * <debugfs>/sync/sw_sync
> - *
> - * That will create a sync timeline, all fences created under this timeline
> - * file descriptor will belong to the this timeline.
> - *
> - * The 'sw_sync' file can be opened many times as to create different
> - * timelines.
> - *
> - * Fences can be created with SW_SYNC_IOC_CREATE_FENCE ioctl with struct
> - * sw_sync_create_fence_data as parameter.
> - *
> - * To increment the timeline counter, SW_SYNC_IOC_INC ioctl should be used
> - * with the increment as u32. This will update the last signaled value
> - * from the timeline and signal any fence that has a seqno smaller or equal
> - * to it.
> - *
> - * struct sw_sync_create_fence_data
> - * @value:	the seqno to initialise the fence with
> - * @name:	the name of the new sync point
> - * @fence:	return the fd of the new sync_file with the created fence
> - */
> -struct sw_sync_create_fence_data {
> -	__u32	value;
> -	char	name[32];
> -	__s32	fence; /* fd of new fence */
> -};
> -
> -#define SW_SYNC_IOC_MAGIC	'W'
> -
> -#define SW_SYNC_IOC_CREATE_FENCE	_IOWR(SW_SYNC_IOC_MAGIC, 0,\
> -		struct sw_sync_create_fence_data)
> -
> -#define SW_SYNC_IOC_INC			_IOW(SW_SYNC_IOC_MAGIC, 1, __u32)
> -
> -static const struct dma_fence_ops timeline_fence_ops;
> -
> -static inline struct sync_pt *dma_fence_to_sync_pt(struct dma_fence *fence)
> -{
> -	if (fence->ops != &timeline_fence_ops)
> -		return NULL;
> -	return container_of(fence, struct sync_pt, base);
> -}
> -
> -/**
> - * sync_timeline_create() - creates a sync object
> - * @name:	sync_timeline name
> - *
> - * Creates a new sync_timeline. Returns the sync_timeline object or NULL in
> - * case of error.
> - */
> -static struct sync_timeline *sync_timeline_create(const char *name)
> -{
> -	struct sync_timeline *obj;
> -
> -	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
> -	if (!obj)
> -		return NULL;
> -
> -	kref_init(&obj->kref);
> -	obj->context = dma_fence_context_alloc(1);
> -	strlcpy(obj->name, name, sizeof(obj->name));
> -
> -	obj->pt_tree = RB_ROOT;
> -	INIT_LIST_HEAD(&obj->pt_list);
> -	spin_lock_init(&obj->lock);
> -
> -	sync_timeline_debug_add(obj);
> -
> -	return obj;
> -}
> -
> -static void sync_timeline_free(struct kref *kref)
> -{
> -	struct sync_timeline *obj =
> -		container_of(kref, struct sync_timeline, kref);
> -
> -	sync_timeline_debug_remove(obj);
> -
> -	kfree(obj);
> -}
> -
> -static void sync_timeline_get(struct sync_timeline *obj)
> -{
> -	kref_get(&obj->kref);
> -}
> -
> -static void sync_timeline_put(struct sync_timeline *obj)
> -{
> -	kref_put(&obj->kref, sync_timeline_free);
> -}
> -
> -static const char *timeline_fence_get_driver_name(struct dma_fence *fence)
> -{
> -	return "sw_sync";
> -}
> -
> -static const char *timeline_fence_get_timeline_name(struct dma_fence *fence)
> -{
> -	struct sync_timeline *parent = dma_fence_parent(fence);
> -
> -	return parent->name;
> -}
> -
> -static void timeline_fence_release(struct dma_fence *fence)
> -{
> -	struct sync_pt *pt = dma_fence_to_sync_pt(fence);
> -	struct sync_timeline *parent = dma_fence_parent(fence);
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(fence->lock, flags);
> -	if (!list_empty(&pt->link)) {
> -		list_del(&pt->link);
> -		rb_erase(&pt->node, &parent->pt_tree);
> -	}
> -	spin_unlock_irqrestore(fence->lock, flags);
> -
> -	sync_timeline_put(parent);
> -	dma_fence_free(fence);
> -}
> -
> -static bool timeline_fence_signaled(struct dma_fence *fence)
> -{
> -	struct sync_timeline *parent = dma_fence_parent(fence);
> -
> -	return !__dma_fence_is_later(fence->seqno, parent->value, fence->ops);
> -}
> -
> -static bool timeline_fence_enable_signaling(struct dma_fence *fence)
> -{
> -	return true;
> -}
> -
> -static void timeline_fence_value_str(struct dma_fence *fence,
> -				    char *str, int size)
> -{
> -	snprintf(str, size, "%lld", fence->seqno);
> -}
> -
> -static void timeline_fence_timeline_value_str(struct dma_fence *fence,
> -					     char *str, int size)
> -{
> -	struct sync_timeline *parent = dma_fence_parent(fence);
> -
> -	snprintf(str, size, "%d", parent->value);
> -}
> -
> -static const struct dma_fence_ops timeline_fence_ops = {
> -	.get_driver_name = timeline_fence_get_driver_name,
> -	.get_timeline_name = timeline_fence_get_timeline_name,
> -	.enable_signaling = timeline_fence_enable_signaling,
> -	.signaled = timeline_fence_signaled,
> -	.release = timeline_fence_release,
> -	.fence_value_str = timeline_fence_value_str,
> -	.timeline_value_str = timeline_fence_timeline_value_str,
> -};
> -
> -/**
> - * sync_timeline_signal() - signal a status change on a sync_timeline
> - * @obj:	sync_timeline to signal
> - * @inc:	num to increment on timeline->value
> - *
> - * A sync implementation should call this any time one of it's fences
> - * has signaled or has an error condition.
> - */
> -static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
> -{
> -	struct sync_pt *pt, *next;
> -
> -	trace_sync_timeline(obj);
> -
> -	spin_lock_irq(&obj->lock);
> -
> -	obj->value += inc;
> -
> -	list_for_each_entry_safe(pt, next, &obj->pt_list, link) {
> -		if (!timeline_fence_signaled(&pt->base))
> -			break;
> -
> -		list_del_init(&pt->link);
> -		rb_erase(&pt->node, &obj->pt_tree);
> -
> -		/*
> -		 * A signal callback may release the last reference to this
> -		 * fence, causing it to be freed. That operation has to be
> -		 * last to avoid a use after free inside this loop, and must
> -		 * be after we remove the fence from the timeline in order to
> -		 * prevent deadlocking on timeline->lock inside
> -		 * timeline_fence_release().
> -		 */
> -		dma_fence_signal_locked(&pt->base);
> -	}
> -
> -	spin_unlock_irq(&obj->lock);
> -}
> -
> -/**
> - * sync_pt_create() - creates a sync pt
> - * @obj:	parent sync_timeline
> - * @value:	value of the fence
> - *
> - * Creates a new sync_pt (fence) as a child of @parent.  @size bytes will be
> - * allocated allowing for implementation specific data to be kept after
> - * the generic sync_timeline struct. Returns the sync_pt object or
> - * NULL in case of error.
> - */
> -static struct sync_pt *sync_pt_create(struct sync_timeline *obj,
> -				      unsigned int value)
> -{
> -	struct sync_pt *pt;
> -
> -	pt = kzalloc(sizeof(*pt), GFP_KERNEL);
> -	if (!pt)
> -		return NULL;
> -
> -	sync_timeline_get(obj);
> -	dma_fence_init(&pt->base, &timeline_fence_ops, &obj->lock,
> -		       obj->context, value);
> -	INIT_LIST_HEAD(&pt->link);
> -
> -	spin_lock_irq(&obj->lock);
> -	if (!dma_fence_is_signaled_locked(&pt->base)) {
> -		struct rb_node **p = &obj->pt_tree.rb_node;
> -		struct rb_node *parent = NULL;
> -
> -		while (*p) {
> -			struct sync_pt *other;
> -			int cmp;
> -
> -			parent = *p;
> -			other = rb_entry(parent, typeof(*pt), node);
> -			cmp = value - other->base.seqno;
> -			if (cmp > 0) {
> -				p = &parent->rb_right;
> -			} else if (cmp < 0) {
> -				p = &parent->rb_left;
> -			} else {
> -				if (dma_fence_get_rcu(&other->base)) {
> -					sync_timeline_put(obj);
> -					kfree(pt);
> -					pt = other;
> -					goto unlock;
> -				}
> -				p = &parent->rb_left;
> -			}
> -		}
> -		rb_link_node(&pt->node, parent, p);
> -		rb_insert_color(&pt->node, &obj->pt_tree);
> -
> -		parent = rb_next(&pt->node);
> -		list_add_tail(&pt->link,
> -			      parent ? &rb_entry(parent, typeof(*pt), node)->link : &obj->pt_list);
> -	}
> -unlock:
> -	spin_unlock_irq(&obj->lock);
> -
> -	return pt;
> -}
> -
> -/*
> - * *WARNING*
> - *
> - * improper use of this can result in deadlocking kernel drivers from userspace.
> - */
> -
> -/* opening sw_sync create a new sync obj */
> -static int sw_sync_debugfs_open(struct inode *inode, struct file *file)
> -{
> -	struct sync_timeline *obj;
> -	char task_comm[TASK_COMM_LEN];
> -
> -	get_task_comm(task_comm, current);
> -
> -	obj = sync_timeline_create(task_comm);
> -	if (!obj)
> -		return -ENOMEM;
> -
> -	file->private_data = obj;
> -
> -	return 0;
> -}
> -
> -static int sw_sync_debugfs_release(struct inode *inode, struct file *file)
> -{
> -	struct sync_timeline *obj = file->private_data;
> -	struct sync_pt *pt, *next;
> -
> -	spin_lock_irq(&obj->lock);
> -
> -	list_for_each_entry_safe(pt, next, &obj->pt_list, link) {
> -		dma_fence_set_error(&pt->base, -ENOENT);
> -		dma_fence_signal_locked(&pt->base);
> -	}
> -
> -	spin_unlock_irq(&obj->lock);
> -
> -	sync_timeline_put(obj);
> -	return 0;
> -}
> -
> -static long sw_sync_ioctl_create_fence(struct sync_timeline *obj,
> -				       unsigned long arg)
> -{
> -	int fd = get_unused_fd_flags(O_CLOEXEC);
> -	int err;
> -	struct sync_pt *pt;
> -	struct sync_file *sync_file;
> -	struct sw_sync_create_fence_data data;
> -
> -	if (fd < 0)
> -		return fd;
> -
> -	if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
> -		err = -EFAULT;
> -		goto err;
> -	}
> -
> -	pt = sync_pt_create(obj, data.value);
> -	if (!pt) {
> -		err = -ENOMEM;
> -		goto err;
> -	}
> -
> -	sync_file = sync_file_create(&pt->base);
> -	dma_fence_put(&pt->base);
> -	if (!sync_file) {
> -		err = -ENOMEM;
> -		goto err;
> -	}
> -
> -	data.fence = fd;
> -	if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
> -		fput(sync_file->file);
> -		err = -EFAULT;
> -		goto err;
> -	}
> -
> -	fd_install(fd, sync_file->file);
> -
> -	return 0;
> -
> -err:
> -	put_unused_fd(fd);
> -	return err;
> -}
> -
> -static long sw_sync_ioctl_inc(struct sync_timeline *obj, unsigned long arg)
> -{
> -	u32 value;
> -
> -	if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
> -		return -EFAULT;
> -
> -	while (value > INT_MAX)  {
> -		sync_timeline_signal(obj, INT_MAX);
> -		value -= INT_MAX;
> -	}
> -
> -	sync_timeline_signal(obj, value);
> -
> -	return 0;
> -}
> -
> -static long sw_sync_ioctl(struct file *file, unsigned int cmd,
> -			  unsigned long arg)
> -{
> -	struct sync_timeline *obj = file->private_data;
> -
> -	switch (cmd) {
> -	case SW_SYNC_IOC_CREATE_FENCE:
> -		return sw_sync_ioctl_create_fence(obj, arg);
> -
> -	case SW_SYNC_IOC_INC:
> -		return sw_sync_ioctl_inc(obj, arg);
> -
> -	default:
> -		return -ENOTTY;
> -	}
> -}
> -
> -const struct file_operations sw_sync_debugfs_fops = {
> -	.open           = sw_sync_debugfs_open,
> -	.release        = sw_sync_debugfs_release,
> -	.unlocked_ioctl = sw_sync_ioctl,
> -	.compat_ioctl	= compat_ptr_ioctl,
> -};
> diff --git a/drivers/dma-buf/sync_debug.c b/drivers/dma-buf/sync_debug.c
> deleted file mode 100644
> index 101394f16930..000000000000
> --- a/drivers/dma-buf/sync_debug.c
> +++ /dev/null
> @@ -1,190 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/*
> - * Sync File validation framework and debug information
> - *
> - * Copyright (C) 2012 Google, Inc.
> - */
> -
> -#include <linux/debugfs.h>
> -#include "sync_debug.h"
> -
> -static struct dentry *dbgfs;
> -
> -static LIST_HEAD(sync_timeline_list_head);
> -static DEFINE_SPINLOCK(sync_timeline_list_lock);
> -static LIST_HEAD(sync_file_list_head);
> -static DEFINE_SPINLOCK(sync_file_list_lock);
> -
> -void sync_timeline_debug_add(struct sync_timeline *obj)
> -{
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&sync_timeline_list_lock, flags);
> -	list_add_tail(&obj->sync_timeline_list, &sync_timeline_list_head);
> -	spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
> -}
> -
> -void sync_timeline_debug_remove(struct sync_timeline *obj)
> -{
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&sync_timeline_list_lock, flags);
> -	list_del(&obj->sync_timeline_list);
> -	spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
> -}
> -
> -void sync_file_debug_add(struct sync_file *sync_file)
> -{
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&sync_file_list_lock, flags);
> -	list_add_tail(&sync_file->sync_file_list, &sync_file_list_head);
> -	spin_unlock_irqrestore(&sync_file_list_lock, flags);
> -}
> -
> -void sync_file_debug_remove(struct sync_file *sync_file)
> -{
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&sync_file_list_lock, flags);
> -	list_del(&sync_file->sync_file_list);
> -	spin_unlock_irqrestore(&sync_file_list_lock, flags);
> -}
> -
> -static const char *sync_status_str(int status)
> -{
> -	if (status < 0)
> -		return "error";
> -
> -	if (status > 0)
> -		return "signaled";
> -
> -	return "active";
> -}
> -
> -static void sync_print_fence(struct seq_file *s,
> -			     struct dma_fence *fence, bool show)
> -{
> -	struct sync_timeline *parent = dma_fence_parent(fence);
> -	int status;
> -
> -	status = dma_fence_get_status_locked(fence);
> -
> -	seq_printf(s, "  %s%sfence %s",
> -		   show ? parent->name : "",
> -		   show ? "_" : "",
> -		   sync_status_str(status));
> -
> -	if (test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags)) {
> -		struct timespec64 ts64 =
> -			ktime_to_timespec64(fence->timestamp);
> -
> -		seq_printf(s, "@%lld.%09ld", (s64)ts64.tv_sec, ts64.tv_nsec);
> -	}
> -
> -	if (fence->ops->timeline_value_str &&
> -		fence->ops->fence_value_str) {
> -		char value[64];
> -		bool success;
> -
> -		fence->ops->fence_value_str(fence, value, sizeof(value));
> -		success = strlen(value);
> -
> -		if (success) {
> -			seq_printf(s, ": %s", value);
> -
> -			fence->ops->timeline_value_str(fence, value,
> -						       sizeof(value));
> -
> -			if (strlen(value))
> -				seq_printf(s, " / %s", value);
> -		}
> -	}
> -
> -	seq_putc(s, '\n');
> -}
> -
> -static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj)
> -{
> -	struct list_head *pos;
> -
> -	seq_printf(s, "%s: %d\n", obj->name, obj->value);
> -
> -	spin_lock_irq(&obj->lock);
> -	list_for_each(pos, &obj->pt_list) {
> -		struct sync_pt *pt = container_of(pos, struct sync_pt, link);
> -		sync_print_fence(s, &pt->base, false);
> -	}
> -	spin_unlock_irq(&obj->lock);
> -}
> -
> -static void sync_print_sync_file(struct seq_file *s,
> -				  struct sync_file *sync_file)
> -{
> -	char buf[128];
> -	int i;
> -
> -	seq_printf(s, "[%p] %s: %s\n", sync_file,
> -		   sync_file_get_name(sync_file, buf, sizeof(buf)),
> -		   sync_status_str(dma_fence_get_status(sync_file->fence)));
> -
> -	if (dma_fence_is_array(sync_file->fence)) {
> -		struct dma_fence_array *array = to_dma_fence_array(sync_file->fence);
> -
> -		for (i = 0; i < array->num_fences; ++i)
> -			sync_print_fence(s, array->fences[i], true);
> -	} else {
> -		sync_print_fence(s, sync_file->fence, true);
> -	}
> -}
> -
> -static int sync_info_debugfs_show(struct seq_file *s, void *unused)
> -{
> -	struct list_head *pos;
> -
> -	seq_puts(s, "objs:\n--------------\n");
> -
> -	spin_lock_irq(&sync_timeline_list_lock);
> -	list_for_each(pos, &sync_timeline_list_head) {
> -		struct sync_timeline *obj =
> -			container_of(pos, struct sync_timeline,
> -				     sync_timeline_list);
> -
> -		sync_print_obj(s, obj);
> -		seq_putc(s, '\n');
> -	}
> -	spin_unlock_irq(&sync_timeline_list_lock);
> -
> -	seq_puts(s, "fences:\n--------------\n");
> -
> -	spin_lock_irq(&sync_file_list_lock);
> -	list_for_each(pos, &sync_file_list_head) {
> -		struct sync_file *sync_file =
> -			container_of(pos, struct sync_file, sync_file_list);
> -
> -		sync_print_sync_file(s, sync_file);
> -		seq_putc(s, '\n');
> -	}
> -	spin_unlock_irq(&sync_file_list_lock);
> -	return 0;
> -}
> -
> -DEFINE_SHOW_ATTRIBUTE(sync_info_debugfs);
> -
> -static __init int sync_debugfs_init(void)
> -{
> -	dbgfs = debugfs_create_dir("sync", NULL);
> -
> -	/*
> -	 * The debugfs files won't ever get removed and thus, there is
> -	 * no need to protect it against removal races. The use of
> -	 * debugfs_create_file_unsafe() is actually safe here.
> -	 */
> -	debugfs_create_file_unsafe("info", 0444, dbgfs, NULL,
> -				   &sync_info_debugfs_fops);
> -	debugfs_create_file_unsafe("sw_sync", 0644, dbgfs, NULL,
> -				   &sw_sync_debugfs_fops);
> -
> -	return 0;
> -}
> -late_initcall(sync_debugfs_init);
> diff --git a/drivers/dma-buf/sync_debug.h b/drivers/dma-buf/sync_debug.h
> deleted file mode 100644
> index 6176e52ba2d7..000000000000
> --- a/drivers/dma-buf/sync_debug.h
> +++ /dev/null
> @@ -1,72 +0,0 @@
> -/*
> - * Sync File validation framework and debug infomation
> - *
> - * Copyright (C) 2012 Google, Inc.
> - *
> - * 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_SYNC_H
> -#define _LINUX_SYNC_H
> -
> -#include <linux/list.h>
> -#include <linux/rbtree.h>
> -#include <linux/spinlock.h>
> -#include <linux/dma-fence.h>
> -
> -#include <linux/sync_file.h>
> -#include <uapi/linux/sync_file.h>
> -
> -/**
> - * struct sync_timeline - sync object
> - * @kref:		reference count on fence.
> - * @name:		name of the sync_timeline. Useful for debugging
> - * @lock:		lock protecting @pt_list and @value
> - * @pt_tree:		rbtree of active (unsignaled/errored) sync_pts
> - * @pt_list:		list of active (unsignaled/errored) sync_pts
> - * @sync_timeline_list:	membership in global sync_timeline_list
> - */
> -struct sync_timeline {
> -	struct kref		kref;
> -	char			name[32];
> -
> -	/* protected by lock */
> -	u64			context;
> -	int			value;
> -
> -	struct rb_root		pt_tree;
> -	struct list_head	pt_list;
> -	spinlock_t		lock;
> -
> -	struct list_head	sync_timeline_list;
> -};
> -
> -static inline struct sync_timeline *dma_fence_parent(struct dma_fence *fence)
> -{
> -	return container_of(fence->lock, struct sync_timeline, lock);
> -}
> -
> -/**
> - * struct sync_pt - sync_pt object
> - * @base: base fence object
> - * @link: link on the sync timeline's list
> - * @node: node in the sync timeline's tree
> - */
> -struct sync_pt {
> -	struct dma_fence base;
> -	struct list_head link;
> -	struct rb_node node;
> -};
> -
> -extern const struct file_operations sw_sync_debugfs_fops;
> -
> -void sync_timeline_debug_add(struct sync_timeline *obj);
> -void sync_timeline_debug_remove(struct sync_timeline *obj);
> -void sync_file_debug_add(struct sync_file *fence);
> -void sync_file_debug_remove(struct sync_file *fence);
> -
> -#endif /* _LINUX_SYNC_H */
> -- 
> 2.25.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

WARNING: multiple messages have this Message-ID
From: Daniel Vetter <daniel@ffwll.ch>
To: "Christian König" <ckoenig.leichtzumerken@gmail.com>
Cc: gustavo@padovan.org, dri-devel@lists.freedesktop.org,
	linaro-mm-sig@lists.linaro.org, linux-media@vger.kernel.org
Subject: Re: [PATCH 3/3] dma-buf: nuke SW_SYNC debugfs files
Date: Thu, 29 Jul 2021 09:23:55 +0200	[thread overview]
Message-ID: <YQJXi2JNZdH5DaR2@phenom.ffwll.local> (raw)
In-Reply-To: <20210729070330.41443-3-christian.koenig@amd.com>

On Thu, Jul 29, 2021 at 09:03:30AM +0200, Christian König wrote:
> As we now knew controlling dma_fence synchronization from userspace is
> extremely dangerous and can not only deadlock drivers but trivially also the
> whole kernel memory management.
> 
> Entirely remove this option. We now have in kernel unit tests to exercise the
> dma_fence framework and it's containers.
> 
> Signed-off-by: Christian König <christian.koenig@amd.com>

There's also igts for this, and Android heavily uses this. So I'm not sure
we can just nuke it.

I guess what we could do is maybe just taint the kernel if it's ever used?

Also for testing we use vgem now, which enforces a timeout.
-Daniel

> ---
>  drivers/dma-buf/Kconfig      |  13 --
>  drivers/dma-buf/Makefile     |   1 -
>  drivers/dma-buf/sw_sync.c    | 412 -----------------------------------
>  drivers/dma-buf/sync_debug.c | 190 ----------------
>  drivers/dma-buf/sync_debug.h |  72 ------
>  5 files changed, 688 deletions(-)
>  delete mode 100644 drivers/dma-buf/sw_sync.c
>  delete mode 100644 drivers/dma-buf/sync_debug.c
>  delete mode 100644 drivers/dma-buf/sync_debug.h
> 
> diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
> index 9561e3d2d428..26c53f45616a 100644
> --- a/drivers/dma-buf/Kconfig
> +++ b/drivers/dma-buf/Kconfig
> @@ -17,19 +17,6 @@ config SYNC_FILE
>  	  Files fds, to the DRM driver for example. More details at
>  	  Documentation/driver-api/sync_file.rst.
>  
> -config SW_SYNC
> -	bool "Sync File Validation Framework"
> -	default n
> -	depends on SYNC_FILE
> -	depends on DEBUG_FS
> -	help
> -	  A sync object driver that uses a 32bit counter to coordinate
> -	  synchronization.  Useful when there is no hardware primitive backing
> -	  the synchronization.
> -
> -	  WARNING: improper use of this can result in deadlocking kernel
> -	  drivers from userspace. Intended for test and debug only.
> -
>  config UDMABUF
>  	bool "userspace dmabuf misc driver"
>  	default n
> diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
> index 1ef021273a06..fa3af0953f87 100644
> --- a/drivers/dma-buf/Makefile
> +++ b/drivers/dma-buf/Makefile
> @@ -4,7 +4,6 @@ obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
>  obj-$(CONFIG_DMABUF_HEAPS)	+= dma-heap.o
>  obj-$(CONFIG_DMABUF_HEAPS)	+= heaps/
>  obj-$(CONFIG_SYNC_FILE)		+= sync_file.o
> -obj-$(CONFIG_SW_SYNC)		+= sw_sync.o sync_debug.o
>  obj-$(CONFIG_UDMABUF)		+= udmabuf.o
>  obj-$(CONFIG_DMABUF_SYSFS_STATS) += dma-buf-sysfs-stats.o
>  
> diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c
> deleted file mode 100644
> index 348b3a9170fa..000000000000
> --- a/drivers/dma-buf/sw_sync.c
> +++ /dev/null
> @@ -1,412 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/*
> - * Sync File validation framework
> - *
> - * Copyright (C) 2012 Google, Inc.
> - */
> -
> -#include <linux/file.h>
> -#include <linux/fs.h>
> -#include <linux/uaccess.h>
> -#include <linux/slab.h>
> -#include <linux/sync_file.h>
> -
> -#include "sync_debug.h"
> -
> -#define CREATE_TRACE_POINTS
> -#include "sync_trace.h"
> -
> -/*
> - * SW SYNC validation framework
> - *
> - * A sync object driver that uses a 32bit counter to coordinate
> - * synchronization.  Useful when there is no hardware primitive backing
> - * the synchronization.
> - *
> - * To start the framework just open:
> - *
> - * <debugfs>/sync/sw_sync
> - *
> - * That will create a sync timeline, all fences created under this timeline
> - * file descriptor will belong to the this timeline.
> - *
> - * The 'sw_sync' file can be opened many times as to create different
> - * timelines.
> - *
> - * Fences can be created with SW_SYNC_IOC_CREATE_FENCE ioctl with struct
> - * sw_sync_create_fence_data as parameter.
> - *
> - * To increment the timeline counter, SW_SYNC_IOC_INC ioctl should be used
> - * with the increment as u32. This will update the last signaled value
> - * from the timeline and signal any fence that has a seqno smaller or equal
> - * to it.
> - *
> - * struct sw_sync_create_fence_data
> - * @value:	the seqno to initialise the fence with
> - * @name:	the name of the new sync point
> - * @fence:	return the fd of the new sync_file with the created fence
> - */
> -struct sw_sync_create_fence_data {
> -	__u32	value;
> -	char	name[32];
> -	__s32	fence; /* fd of new fence */
> -};
> -
> -#define SW_SYNC_IOC_MAGIC	'W'
> -
> -#define SW_SYNC_IOC_CREATE_FENCE	_IOWR(SW_SYNC_IOC_MAGIC, 0,\
> -		struct sw_sync_create_fence_data)
> -
> -#define SW_SYNC_IOC_INC			_IOW(SW_SYNC_IOC_MAGIC, 1, __u32)
> -
> -static const struct dma_fence_ops timeline_fence_ops;
> -
> -static inline struct sync_pt *dma_fence_to_sync_pt(struct dma_fence *fence)
> -{
> -	if (fence->ops != &timeline_fence_ops)
> -		return NULL;
> -	return container_of(fence, struct sync_pt, base);
> -}
> -
> -/**
> - * sync_timeline_create() - creates a sync object
> - * @name:	sync_timeline name
> - *
> - * Creates a new sync_timeline. Returns the sync_timeline object or NULL in
> - * case of error.
> - */
> -static struct sync_timeline *sync_timeline_create(const char *name)
> -{
> -	struct sync_timeline *obj;
> -
> -	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
> -	if (!obj)
> -		return NULL;
> -
> -	kref_init(&obj->kref);
> -	obj->context = dma_fence_context_alloc(1);
> -	strlcpy(obj->name, name, sizeof(obj->name));
> -
> -	obj->pt_tree = RB_ROOT;
> -	INIT_LIST_HEAD(&obj->pt_list);
> -	spin_lock_init(&obj->lock);
> -
> -	sync_timeline_debug_add(obj);
> -
> -	return obj;
> -}
> -
> -static void sync_timeline_free(struct kref *kref)
> -{
> -	struct sync_timeline *obj =
> -		container_of(kref, struct sync_timeline, kref);
> -
> -	sync_timeline_debug_remove(obj);
> -
> -	kfree(obj);
> -}
> -
> -static void sync_timeline_get(struct sync_timeline *obj)
> -{
> -	kref_get(&obj->kref);
> -}
> -
> -static void sync_timeline_put(struct sync_timeline *obj)
> -{
> -	kref_put(&obj->kref, sync_timeline_free);
> -}
> -
> -static const char *timeline_fence_get_driver_name(struct dma_fence *fence)
> -{
> -	return "sw_sync";
> -}
> -
> -static const char *timeline_fence_get_timeline_name(struct dma_fence *fence)
> -{
> -	struct sync_timeline *parent = dma_fence_parent(fence);
> -
> -	return parent->name;
> -}
> -
> -static void timeline_fence_release(struct dma_fence *fence)
> -{
> -	struct sync_pt *pt = dma_fence_to_sync_pt(fence);
> -	struct sync_timeline *parent = dma_fence_parent(fence);
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(fence->lock, flags);
> -	if (!list_empty(&pt->link)) {
> -		list_del(&pt->link);
> -		rb_erase(&pt->node, &parent->pt_tree);
> -	}
> -	spin_unlock_irqrestore(fence->lock, flags);
> -
> -	sync_timeline_put(parent);
> -	dma_fence_free(fence);
> -}
> -
> -static bool timeline_fence_signaled(struct dma_fence *fence)
> -{
> -	struct sync_timeline *parent = dma_fence_parent(fence);
> -
> -	return !__dma_fence_is_later(fence->seqno, parent->value, fence->ops);
> -}
> -
> -static bool timeline_fence_enable_signaling(struct dma_fence *fence)
> -{
> -	return true;
> -}
> -
> -static void timeline_fence_value_str(struct dma_fence *fence,
> -				    char *str, int size)
> -{
> -	snprintf(str, size, "%lld", fence->seqno);
> -}
> -
> -static void timeline_fence_timeline_value_str(struct dma_fence *fence,
> -					     char *str, int size)
> -{
> -	struct sync_timeline *parent = dma_fence_parent(fence);
> -
> -	snprintf(str, size, "%d", parent->value);
> -}
> -
> -static const struct dma_fence_ops timeline_fence_ops = {
> -	.get_driver_name = timeline_fence_get_driver_name,
> -	.get_timeline_name = timeline_fence_get_timeline_name,
> -	.enable_signaling = timeline_fence_enable_signaling,
> -	.signaled = timeline_fence_signaled,
> -	.release = timeline_fence_release,
> -	.fence_value_str = timeline_fence_value_str,
> -	.timeline_value_str = timeline_fence_timeline_value_str,
> -};
> -
> -/**
> - * sync_timeline_signal() - signal a status change on a sync_timeline
> - * @obj:	sync_timeline to signal
> - * @inc:	num to increment on timeline->value
> - *
> - * A sync implementation should call this any time one of it's fences
> - * has signaled or has an error condition.
> - */
> -static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
> -{
> -	struct sync_pt *pt, *next;
> -
> -	trace_sync_timeline(obj);
> -
> -	spin_lock_irq(&obj->lock);
> -
> -	obj->value += inc;
> -
> -	list_for_each_entry_safe(pt, next, &obj->pt_list, link) {
> -		if (!timeline_fence_signaled(&pt->base))
> -			break;
> -
> -		list_del_init(&pt->link);
> -		rb_erase(&pt->node, &obj->pt_tree);
> -
> -		/*
> -		 * A signal callback may release the last reference to this
> -		 * fence, causing it to be freed. That operation has to be
> -		 * last to avoid a use after free inside this loop, and must
> -		 * be after we remove the fence from the timeline in order to
> -		 * prevent deadlocking on timeline->lock inside
> -		 * timeline_fence_release().
> -		 */
> -		dma_fence_signal_locked(&pt->base);
> -	}
> -
> -	spin_unlock_irq(&obj->lock);
> -}
> -
> -/**
> - * sync_pt_create() - creates a sync pt
> - * @obj:	parent sync_timeline
> - * @value:	value of the fence
> - *
> - * Creates a new sync_pt (fence) as a child of @parent.  @size bytes will be
> - * allocated allowing for implementation specific data to be kept after
> - * the generic sync_timeline struct. Returns the sync_pt object or
> - * NULL in case of error.
> - */
> -static struct sync_pt *sync_pt_create(struct sync_timeline *obj,
> -				      unsigned int value)
> -{
> -	struct sync_pt *pt;
> -
> -	pt = kzalloc(sizeof(*pt), GFP_KERNEL);
> -	if (!pt)
> -		return NULL;
> -
> -	sync_timeline_get(obj);
> -	dma_fence_init(&pt->base, &timeline_fence_ops, &obj->lock,
> -		       obj->context, value);
> -	INIT_LIST_HEAD(&pt->link);
> -
> -	spin_lock_irq(&obj->lock);
> -	if (!dma_fence_is_signaled_locked(&pt->base)) {
> -		struct rb_node **p = &obj->pt_tree.rb_node;
> -		struct rb_node *parent = NULL;
> -
> -		while (*p) {
> -			struct sync_pt *other;
> -			int cmp;
> -
> -			parent = *p;
> -			other = rb_entry(parent, typeof(*pt), node);
> -			cmp = value - other->base.seqno;
> -			if (cmp > 0) {
> -				p = &parent->rb_right;
> -			} else if (cmp < 0) {
> -				p = &parent->rb_left;
> -			} else {
> -				if (dma_fence_get_rcu(&other->base)) {
> -					sync_timeline_put(obj);
> -					kfree(pt);
> -					pt = other;
> -					goto unlock;
> -				}
> -				p = &parent->rb_left;
> -			}
> -		}
> -		rb_link_node(&pt->node, parent, p);
> -		rb_insert_color(&pt->node, &obj->pt_tree);
> -
> -		parent = rb_next(&pt->node);
> -		list_add_tail(&pt->link,
> -			      parent ? &rb_entry(parent, typeof(*pt), node)->link : &obj->pt_list);
> -	}
> -unlock:
> -	spin_unlock_irq(&obj->lock);
> -
> -	return pt;
> -}
> -
> -/*
> - * *WARNING*
> - *
> - * improper use of this can result in deadlocking kernel drivers from userspace.
> - */
> -
> -/* opening sw_sync create a new sync obj */
> -static int sw_sync_debugfs_open(struct inode *inode, struct file *file)
> -{
> -	struct sync_timeline *obj;
> -	char task_comm[TASK_COMM_LEN];
> -
> -	get_task_comm(task_comm, current);
> -
> -	obj = sync_timeline_create(task_comm);
> -	if (!obj)
> -		return -ENOMEM;
> -
> -	file->private_data = obj;
> -
> -	return 0;
> -}
> -
> -static int sw_sync_debugfs_release(struct inode *inode, struct file *file)
> -{
> -	struct sync_timeline *obj = file->private_data;
> -	struct sync_pt *pt, *next;
> -
> -	spin_lock_irq(&obj->lock);
> -
> -	list_for_each_entry_safe(pt, next, &obj->pt_list, link) {
> -		dma_fence_set_error(&pt->base, -ENOENT);
> -		dma_fence_signal_locked(&pt->base);
> -	}
> -
> -	spin_unlock_irq(&obj->lock);
> -
> -	sync_timeline_put(obj);
> -	return 0;
> -}
> -
> -static long sw_sync_ioctl_create_fence(struct sync_timeline *obj,
> -				       unsigned long arg)
> -{
> -	int fd = get_unused_fd_flags(O_CLOEXEC);
> -	int err;
> -	struct sync_pt *pt;
> -	struct sync_file *sync_file;
> -	struct sw_sync_create_fence_data data;
> -
> -	if (fd < 0)
> -		return fd;
> -
> -	if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
> -		err = -EFAULT;
> -		goto err;
> -	}
> -
> -	pt = sync_pt_create(obj, data.value);
> -	if (!pt) {
> -		err = -ENOMEM;
> -		goto err;
> -	}
> -
> -	sync_file = sync_file_create(&pt->base);
> -	dma_fence_put(&pt->base);
> -	if (!sync_file) {
> -		err = -ENOMEM;
> -		goto err;
> -	}
> -
> -	data.fence = fd;
> -	if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
> -		fput(sync_file->file);
> -		err = -EFAULT;
> -		goto err;
> -	}
> -
> -	fd_install(fd, sync_file->file);
> -
> -	return 0;
> -
> -err:
> -	put_unused_fd(fd);
> -	return err;
> -}
> -
> -static long sw_sync_ioctl_inc(struct sync_timeline *obj, unsigned long arg)
> -{
> -	u32 value;
> -
> -	if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
> -		return -EFAULT;
> -
> -	while (value > INT_MAX)  {
> -		sync_timeline_signal(obj, INT_MAX);
> -		value -= INT_MAX;
> -	}
> -
> -	sync_timeline_signal(obj, value);
> -
> -	return 0;
> -}
> -
> -static long sw_sync_ioctl(struct file *file, unsigned int cmd,
> -			  unsigned long arg)
> -{
> -	struct sync_timeline *obj = file->private_data;
> -
> -	switch (cmd) {
> -	case SW_SYNC_IOC_CREATE_FENCE:
> -		return sw_sync_ioctl_create_fence(obj, arg);
> -
> -	case SW_SYNC_IOC_INC:
> -		return sw_sync_ioctl_inc(obj, arg);
> -
> -	default:
> -		return -ENOTTY;
> -	}
> -}
> -
> -const struct file_operations sw_sync_debugfs_fops = {
> -	.open           = sw_sync_debugfs_open,
> -	.release        = sw_sync_debugfs_release,
> -	.unlocked_ioctl = sw_sync_ioctl,
> -	.compat_ioctl	= compat_ptr_ioctl,
> -};
> diff --git a/drivers/dma-buf/sync_debug.c b/drivers/dma-buf/sync_debug.c
> deleted file mode 100644
> index 101394f16930..000000000000
> --- a/drivers/dma-buf/sync_debug.c
> +++ /dev/null
> @@ -1,190 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/*
> - * Sync File validation framework and debug information
> - *
> - * Copyright (C) 2012 Google, Inc.
> - */
> -
> -#include <linux/debugfs.h>
> -#include "sync_debug.h"
> -
> -static struct dentry *dbgfs;
> -
> -static LIST_HEAD(sync_timeline_list_head);
> -static DEFINE_SPINLOCK(sync_timeline_list_lock);
> -static LIST_HEAD(sync_file_list_head);
> -static DEFINE_SPINLOCK(sync_file_list_lock);
> -
> -void sync_timeline_debug_add(struct sync_timeline *obj)
> -{
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&sync_timeline_list_lock, flags);
> -	list_add_tail(&obj->sync_timeline_list, &sync_timeline_list_head);
> -	spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
> -}
> -
> -void sync_timeline_debug_remove(struct sync_timeline *obj)
> -{
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&sync_timeline_list_lock, flags);
> -	list_del(&obj->sync_timeline_list);
> -	spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
> -}
> -
> -void sync_file_debug_add(struct sync_file *sync_file)
> -{
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&sync_file_list_lock, flags);
> -	list_add_tail(&sync_file->sync_file_list, &sync_file_list_head);
> -	spin_unlock_irqrestore(&sync_file_list_lock, flags);
> -}
> -
> -void sync_file_debug_remove(struct sync_file *sync_file)
> -{
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&sync_file_list_lock, flags);
> -	list_del(&sync_file->sync_file_list);
> -	spin_unlock_irqrestore(&sync_file_list_lock, flags);
> -}
> -
> -static const char *sync_status_str(int status)
> -{
> -	if (status < 0)
> -		return "error";
> -
> -	if (status > 0)
> -		return "signaled";
> -
> -	return "active";
> -}
> -
> -static void sync_print_fence(struct seq_file *s,
> -			     struct dma_fence *fence, bool show)
> -{
> -	struct sync_timeline *parent = dma_fence_parent(fence);
> -	int status;
> -
> -	status = dma_fence_get_status_locked(fence);
> -
> -	seq_printf(s, "  %s%sfence %s",
> -		   show ? parent->name : "",
> -		   show ? "_" : "",
> -		   sync_status_str(status));
> -
> -	if (test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags)) {
> -		struct timespec64 ts64 =
> -			ktime_to_timespec64(fence->timestamp);
> -
> -		seq_printf(s, "@%lld.%09ld", (s64)ts64.tv_sec, ts64.tv_nsec);
> -	}
> -
> -	if (fence->ops->timeline_value_str &&
> -		fence->ops->fence_value_str) {
> -		char value[64];
> -		bool success;
> -
> -		fence->ops->fence_value_str(fence, value, sizeof(value));
> -		success = strlen(value);
> -
> -		if (success) {
> -			seq_printf(s, ": %s", value);
> -
> -			fence->ops->timeline_value_str(fence, value,
> -						       sizeof(value));
> -
> -			if (strlen(value))
> -				seq_printf(s, " / %s", value);
> -		}
> -	}
> -
> -	seq_putc(s, '\n');
> -}
> -
> -static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj)
> -{
> -	struct list_head *pos;
> -
> -	seq_printf(s, "%s: %d\n", obj->name, obj->value);
> -
> -	spin_lock_irq(&obj->lock);
> -	list_for_each(pos, &obj->pt_list) {
> -		struct sync_pt *pt = container_of(pos, struct sync_pt, link);
> -		sync_print_fence(s, &pt->base, false);
> -	}
> -	spin_unlock_irq(&obj->lock);
> -}
> -
> -static void sync_print_sync_file(struct seq_file *s,
> -				  struct sync_file *sync_file)
> -{
> -	char buf[128];
> -	int i;
> -
> -	seq_printf(s, "[%p] %s: %s\n", sync_file,
> -		   sync_file_get_name(sync_file, buf, sizeof(buf)),
> -		   sync_status_str(dma_fence_get_status(sync_file->fence)));
> -
> -	if (dma_fence_is_array(sync_file->fence)) {
> -		struct dma_fence_array *array = to_dma_fence_array(sync_file->fence);
> -
> -		for (i = 0; i < array->num_fences; ++i)
> -			sync_print_fence(s, array->fences[i], true);
> -	} else {
> -		sync_print_fence(s, sync_file->fence, true);
> -	}
> -}
> -
> -static int sync_info_debugfs_show(struct seq_file *s, void *unused)
> -{
> -	struct list_head *pos;
> -
> -	seq_puts(s, "objs:\n--------------\n");
> -
> -	spin_lock_irq(&sync_timeline_list_lock);
> -	list_for_each(pos, &sync_timeline_list_head) {
> -		struct sync_timeline *obj =
> -			container_of(pos, struct sync_timeline,
> -				     sync_timeline_list);
> -
> -		sync_print_obj(s, obj);
> -		seq_putc(s, '\n');
> -	}
> -	spin_unlock_irq(&sync_timeline_list_lock);
> -
> -	seq_puts(s, "fences:\n--------------\n");
> -
> -	spin_lock_irq(&sync_file_list_lock);
> -	list_for_each(pos, &sync_file_list_head) {
> -		struct sync_file *sync_file =
> -			container_of(pos, struct sync_file, sync_file_list);
> -
> -		sync_print_sync_file(s, sync_file);
> -		seq_putc(s, '\n');
> -	}
> -	spin_unlock_irq(&sync_file_list_lock);
> -	return 0;
> -}
> -
> -DEFINE_SHOW_ATTRIBUTE(sync_info_debugfs);
> -
> -static __init int sync_debugfs_init(void)
> -{
> -	dbgfs = debugfs_create_dir("sync", NULL);
> -
> -	/*
> -	 * The debugfs files won't ever get removed and thus, there is
> -	 * no need to protect it against removal races. The use of
> -	 * debugfs_create_file_unsafe() is actually safe here.
> -	 */
> -	debugfs_create_file_unsafe("info", 0444, dbgfs, NULL,
> -				   &sync_info_debugfs_fops);
> -	debugfs_create_file_unsafe("sw_sync", 0644, dbgfs, NULL,
> -				   &sw_sync_debugfs_fops);
> -
> -	return 0;
> -}
> -late_initcall(sync_debugfs_init);
> diff --git a/drivers/dma-buf/sync_debug.h b/drivers/dma-buf/sync_debug.h
> deleted file mode 100644
> index 6176e52ba2d7..000000000000
> --- a/drivers/dma-buf/sync_debug.h
> +++ /dev/null
> @@ -1,72 +0,0 @@
> -/*
> - * Sync File validation framework and debug infomation
> - *
> - * Copyright (C) 2012 Google, Inc.
> - *
> - * 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_SYNC_H
> -#define _LINUX_SYNC_H
> -
> -#include <linux/list.h>
> -#include <linux/rbtree.h>
> -#include <linux/spinlock.h>
> -#include <linux/dma-fence.h>
> -
> -#include <linux/sync_file.h>
> -#include <uapi/linux/sync_file.h>
> -
> -/**
> - * struct sync_timeline - sync object
> - * @kref:		reference count on fence.
> - * @name:		name of the sync_timeline. Useful for debugging
> - * @lock:		lock protecting @pt_list and @value
> - * @pt_tree:		rbtree of active (unsignaled/errored) sync_pts
> - * @pt_list:		list of active (unsignaled/errored) sync_pts
> - * @sync_timeline_list:	membership in global sync_timeline_list
> - */
> -struct sync_timeline {
> -	struct kref		kref;
> -	char			name[32];
> -
> -	/* protected by lock */
> -	u64			context;
> -	int			value;
> -
> -	struct rb_root		pt_tree;
> -	struct list_head	pt_list;
> -	spinlock_t		lock;
> -
> -	struct list_head	sync_timeline_list;
> -};
> -
> -static inline struct sync_timeline *dma_fence_parent(struct dma_fence *fence)
> -{
> -	return container_of(fence->lock, struct sync_timeline, lock);
> -}
> -
> -/**
> - * struct sync_pt - sync_pt object
> - * @base: base fence object
> - * @link: link on the sync timeline's list
> - * @node: node in the sync timeline's tree
> - */
> -struct sync_pt {
> -	struct dma_fence base;
> -	struct list_head link;
> -	struct rb_node node;
> -};
> -
> -extern const struct file_operations sw_sync_debugfs_fops;
> -
> -void sync_timeline_debug_add(struct sync_timeline *obj);
> -void sync_timeline_debug_remove(struct sync_timeline *obj);
> -void sync_file_debug_add(struct sync_file *fence);
> -void sync_file_debug_remove(struct sync_file *fence);
> -
> -#endif /* _LINUX_SYNC_H */
> -- 
> 2.25.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

  reply	other threads:[~2021-07-29  7:24 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-29  7:03 [PATCH 1/3] dma-buf: nuke seqno-fence Christian König
2021-07-29  7:03 ` [PATCH 2/3] dma-buf: nuke DMA_FENCE_TRACE macros Christian König
2021-07-29  7:22   ` Daniel Vetter
2021-07-29  7:22     ` Daniel Vetter
2021-07-29  7:24     ` Christian König
2021-07-29  7:24       ` Christian König
2021-07-29  7:03 ` [PATCH 3/3] dma-buf: nuke SW_SYNC debugfs files Christian König
2021-07-29  7:23   ` Daniel Vetter [this message]
2021-07-29  7:23     ` Daniel Vetter
2021-07-29  8:38     ` Christian König
2021-07-29  8:38       ` Christian König
2021-07-29  9:03       ` Daniel Vetter
2021-07-29  9:03         ` Daniel Vetter
2021-07-29 10:21         ` Christian König
2021-07-29 10:21           ` Christian König
2021-07-29 11:59           ` Daniel Vetter
2021-07-29 11:59             ` Daniel Vetter
2021-07-29 12:25             ` Christian König
2021-07-29 12:25               ` Christian König
2021-07-29 12:31               ` Daniel Vetter
2021-07-29 12:31                 ` Daniel Vetter
2021-07-30  4:52     ` John Stultz
2021-07-30  4:52       ` John Stultz
2021-07-30 20:46       ` Hridya Valsaraju
2021-07-29  7:24 ` [PATCH 1/3] dma-buf: nuke seqno-fence Daniel Vetter
2021-07-29  7:24   ` Daniel Vetter

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