| Message ID | 20240625112425.37172-1-fusibrandon13@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v3,v4l-utils] common: Use posix_memalign for allocating userptr buffers | expand |
diff --git a/utils/common/v4l-helpers.h b/utils/common/v4l-helpers.h index cf0e92d..aa9ee26 100644 --- a/utils/common/v4l-helpers.h +++ b/utils/common/v4l-helpers.h @@ -1661,10 +1661,11 @@ static inline int v4l_queue_alloc_bufs(struct v4l_fd *f, return 0; for (b = from; b < v4l_queue_g_buffers(q); b++) { for (p = 0; p < v4l_queue_g_num_planes(q); p++) { - void *m = malloc(v4l_queue_g_length(q, p)); - - if (m == NULL) - return errno; + void *m; + int ret = posix_memalign(&m, getpagesize(), + v4l_queue_g_length(q, p)); + if (ret) + return ret; v4l_queue_s_userptr(q, b, p, m); } }
When dealing with a userptr pointing to a buffer in userspace, videobuf2 swaps the corresponding physical pages with other pages so we have a contiguous area of memory for DMA. This only works if the userptr is page aligned. The current way of allocating user buffers using malloc only guarantees alignment up to `alignof(max_align_t)`, which is usually 16. So replace malloc with posix_memalign to ensure the returned pointer is on a page boundary. Signed-off-by: Brandon Cheo Fusi <fusibrandon13@gmail.com> --- utils/common/v4l-helpers.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)