[PATCH v1 2/4] staging: media: tegra-vde: Manually pack UAPI structures

[Dmitry Osipenko]

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@xxxxxxxxx>
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
 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)
 
-- 
2.21.0