[PATCH v3 2/4] staging: media: tegra-vde: Manually pack UAPI structures

Dmitry Osipenko
2019-06-23T17:08:32Z

The __packed macro isn't available in userspace with the kernel headers.
Checkpatch asks to use the macro, which is unwanted in a case of a UAPI
header. There is no much benefit in a tight packing of the structures,
hence let's pack them manually to cleanup things a tad. Note that there
is no old-stable userspace that will suffer from this change, hence it's
fine to change the ABI. In a result also more space is reserved for a
possible future expansion of the UAPI as it was already shown that more
fields will be needed for a later SoC generations.

Suggested-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/staging/media/tegra-vde/tegra-vde.c | 13 +++++-
drivers/staging/media/tegra-vde/uapi.h | 44 +++++++++++----------
2 files changed, 34 insertions(+), 23 deletions(-)

diff --git a/drivers/staging/media/tegra-vde/tegra-vde.c b/drivers/staging/media/tegra-vde/tegra-vde.c
index a5020dbf6eef..cc4244da2705 100644
--- a/drivers/staging/media/tegra-vde/tegra-vde.c
+++ b/drivers/staging/media/tegra-vde/tegra-vde.c
@@ -795,7 +795,7 @@ static int tegra_vde_ioctl_decode_h264(struct tegra_vde *vde,
{
struct device *dev = vde->miscdev.parent;
struct tegra_vde_h264_decoder_ctx ctx;
- struct tegra_vde_h264_frame frames[17];
+ struct tegra_vde_h264_frame *frames;
struct tegra_vde_h264_frame __user *frames_user;
struct video_frame *dpb_frames;
struct dma_buf_attachment *bitstream_data_dmabuf_attachment;
@@ -830,11 +830,17 @@ static int tegra_vde_ioctl_decode_h264(struct tegra_vde *vde,
if (ret)
return ret;

+ frames = kmalloc_array(ctx.dpb_frames_nb, sizeof(*frames), GFP_KERNEL);
+ if (!frames) {
+ ret = -ENOMEM;
+ goto release_bitstream_dmabuf;
+ }
+
dpb_frames = kcalloc(ctx.dpb_frames_nb, sizeof(*dpb_frames),
GFP_KERNEL);
if (!dpb_frames) {
ret = -ENOMEM;
- goto release_bitstream_dmabuf;
+ goto free_frames;
}

macroblocks_nb = ctx.pic_width_in_mbs * ctx.pic_height_in_mbs;
@@ -955,6 +961,9 @@ static int tegra_vde_ioctl_decode_h264(struct tegra_vde *vde,
free_dpb_frames:
kfree(dpb_frames);

+free_frames:
+ kfree(frames);
+
release_bitstream_dmabuf:
tegra_vde_detach_and_put_dmabuf(bitstream_data_dmabuf_attachment,
bitstream_sgt, DMA_TO_DEVICE);
diff --git a/drivers/staging/media/tegra-vde/uapi.h b/drivers/staging/media/tegra-vde/uapi.h
index dd3e4a8c9f7e..ffb4983e5bb6 100644
--- a/drivers/staging/media/tegra-vde/uapi.h
+++ b/drivers/staging/media/tegra-vde/uapi.h
@@ -21,40 +21,42 @@ struct tegra_vde_h264_frame {
__u32 frame_num;
__u32 flags;

- __u32 reserved;
-} __attribute__((packed));
+ // Must be zero'ed
+ __u32 reserved[6];
+};

struct tegra_vde_h264_decoder_ctx {
__s32 bitstream_data_fd;
__u32 bitstream_data_offset;

__u64 dpb_frames_ptr;
- __u8 dpb_frames_nb;
- __u8 dpb_ref_frames_with_earlier_poc_nb;
+ __u32 dpb_frames_nb;
+ __u32 dpb_ref_frames_with_earlier_poc_nb;

// SPS
- __u8 baseline_profile;
- __u8 level_idc;
- __u8 log2_max_pic_order_cnt_lsb;
- __u8 log2_max_frame_num;
- __u8 pic_order_cnt_type;
- __u8 direct_8x8_inference_flag;
- __u8 pic_width_in_mbs;
- __u8 pic_height_in_mbs;
+ __u32 baseline_profile;
+ __u32 level_idc;
+ __u32 log2_max_pic_order_cnt_lsb;
+ __u32 log2_max_frame_num;
+ __u32 pic_order_cnt_type;
+ __u32 direct_8x8_inference_flag;
+ __u32 pic_width_in_mbs;
+ __u32 pic_height_in_mbs;

// PPS
- __u8 pic_init_qp;
- __u8 deblocking_filter_control_present_flag;
- __u8 constrained_intra_pred_flag;
- __u8 chroma_qp_index_offset;
- __u8 pic_order_present_flag;
+ __u32 pic_init_qp;
+ __u32 deblocking_filter_control_present_flag;
+ __u32 constrained_intra_pred_flag;
+ __u32 chroma_qp_index_offset;
+ __u32 pic_order_present_flag;

// Slice header
- __u8 num_ref_idx_l0_active_minus1;
- __u8 num_ref_idx_l1_active_minus1;
+ __u32 num_ref_idx_l0_active_minus1;
+ __u32 num_ref_idx_l1_active_minus1;

- __u32 reserved;
-} __attribute__((packed));
+ // Must be zero'ed
+ __u32 reserved[11];
+};

#define VDE_IOCTL_BASE ('v' + 0x20)

--
2.22.0