dma: map_benchmark: turn dma_sg_map_param buf into a flexible array

The buf pointer was kmalloc_array()'d immediately after the parent
struct allocation, with the count (granule, validated to 1..1024 by
the ioctl) trivially available beforehand.  Move buf to the struct
tail as a flexible array member and fold the two allocations into a
single kzalloc_flex(), dropping the kfree(params->buf) in both the
prepare error path and unprepare.

Add __counted_by for extra runtime analysis.

Assisted-by: Claude:Opus-4.7
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Qinxin Xia <xiaqinxin@huawei.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260603031758.290538-1-rosenp@gmail.com

0 files changed, 0 insertions, 0 deletions