On Mon, Dec 02, 2019 at 10:41:04PM +0800, Jun Nie wrote: > DMA memory cannot cross specific boundary for some SDHCI controller, > such as DesignWare SDHCI controller. Add DMA memory boundary dt > property and workaround the limitation. If you use blk_queue_segment_boundary to tell the block layer the segment boundary restrictions it won't ever send you segments that don't fit. With just the workaround in this patch you'll run into max_segments accounting issues, don't you?