Linux DMA address
From: Klaus Wacker <hidden>
Date: 2012-07-02 11:44:12
Hello, in the context of ib memory management on Linux we are going to use ib_get_dma_mr() in conjunction with ib_dma_map_single(). The ib_dma_map_single is described as "Map a kernel virtual address to DMA address", i have a question on the returned value "DMA address". I learned somewhere that DMA address is not necessarily a 64-bit real address. When we call ib_dma_map_single() with same buffer-address, size and dma_data_direction, but with different ib_devs. Would that generate the same Linux DMA address on all ib devices? Sure we will have controls in place that not both devices write into the buffer simultaneously. So whats the nature of the returned DMA address of ib_dma_map_single and can we assume that it is the same value on different devices on one system? Thanks for your time spending on this topic. Kind regards Klaus Wacker IBM Systems &Technology Group, Systems Software Development SW Linux on System z Dev & Service Phone: +49-7031-16-3779 IBM Deutschland E-Mail: kdwacker-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org Schoenaicher Str. 220 71032 Boeblingen, Germany IBM Deutschland Research & Development GmbH / Vorsitzende des Aufsichtsrats: Martina Koederitz Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html