Hi Maarten,
2016-02-01 Maarten Lankhorst maarten.lankhorst@linux.intel.com:
Op 29-01-16 om 22:20 schreef Gustavo Padovan:
From: Gustavo Padovan gustavo.padovan@collabora.co.uk
Making fence_info a pointer enables us to extend the struct in the future without breaking the ABI.
Signed-off-by: Gustavo Padovan gustavo.padovan@collabora.co.uk
drivers/staging/android/sync.c | 2 +- drivers/staging/android/uapi/sync.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/android/sync.c b/drivers/staging/android/sync.c index f7530f0..51d4f47 100644 --- a/drivers/staging/android/sync.c +++ b/drivers/staging/android/sync.c @@ -525,7 +525,7 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file, if (info->status >= 0) info->status = !info->status;
- len = sizeof(struct sync_file_info);
len = sizeof(struct sync_file_info) - sizeof(__u64 *);
for (i = 0; i < sync_file->num_fences; ++i) { struct fence *fence = sync_file->cbs[i].fence;
diff --git a/drivers/staging/android/uapi/sync.h b/drivers/staging/android/uapi/sync.h index ed281fc..9f07aa7 100644 --- a/drivers/staging/android/uapi/sync.h +++ b/drivers/staging/android/uapi/sync.h @@ -54,7 +54,7 @@ struct sync_file_info { char name[32]; __s32 status;
- __u8 fence_info[0];
- __u64 *fence_info;
};
Pointers are awful, it should be a __u64 since it's a pointer type. Userspace should cast it to a uintptr_t in userspace.
Oh, I made a mistake. I'll fix this.
This structure also won't work on 64-bits systems, there may be a hole between fence_info and status (or num_fences in next patch).
It's probably best to move it to the top and ensure the struct is 64-bits aligned.
That is not possible because we are not allocating only 64bits there but a array of struct fence_info, so it needs to be the last one. Maybe we can add some sort of padding?
Gustavo