linux_dsm_epyc7002/include/linux/sync_file.h
Gustavo Padovan e241655373 dma-buf/sync_file: only enable fence signalling on poll()
Signalling doesn't need to be enabled at sync_file creation, it is only
required if userspace waiting the fence to signal through poll().

Thus we delay fence_add_callback() until poll is called. It only adds the
callback the first time poll() is called. This avoid re-adding the same
callback multiple times.

v2: rebase and update to work with new fence support for sync_file

v3: use atomic operation to set enabled and protect fence_add_callback()

v4: use user bit from fence flags (comment from Chris Wilson)

v5: use ternary if on poll return (comment from Chris Wilson)

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
  [sumits: remove unused var status]
Link: http://patchwork.freedesktop.org/patch/msgid/1470404378-27961-1-git-send-email-gustavo@padovan.org
2016-08-11 15:39:38 +05:30

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C

/*
* include/linux/sync_file.h
*
* 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_FILE_H
#define _LINUX_SYNC_FILE_H
#include <linux/types.h>
#include <linux/kref.h>
#include <linux/ktime.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/fence.h>
#include <linux/fence-array.h>
/**
* struct sync_file - sync file to export to the userspace
* @file: file representing this fence
* @kref: reference count on fence.
* @name: name of sync_file. Useful for debugging
* @sync_file_list: membership in global file list
* @wq: wait queue for fence signaling
* @fence: fence with the fences in the sync_file
* @cb: fence callback information
*/
struct sync_file {
struct file *file;
struct kref kref;
char name[32];
#ifdef CONFIG_DEBUG_FS
struct list_head sync_file_list;
#endif
wait_queue_head_t wq;
struct fence *fence;
struct fence_cb cb;
};
#define POLL_ENABLED FENCE_FLAG_USER_BITS
struct sync_file *sync_file_create(struct fence *fence);
struct fence *sync_file_get_fence(int fd);
#endif /* _LINUX_SYNC_H */