We use dma_map_single here because we have a virtual pointer and not a page. If you look in the kernel at the file include/asm-generic/dma-mapping-common.h you will see that dma_map_single_attrs which is what ends up being called when we call dma_map_single will convert the pointer to a page and then call map_page. This way we don't have to place the overhead for the code directly in our driver.
Thanks, Alex On 10/25/2012 01:58 AM, ratheesh kannoth wrote: > Hi , > > I was looking at tx_map ( igb-3.3.6 ) in igb driver. I could see that > dma_map_single is used for first buffer and dma_map_page is used for > the fragments. > > What is the real difference between these api ? we can replace > dma_map_single with dma_map_page. then why we used dma_map_single > here ?. > > Thanks, > Ratheesh > ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_sfd2d_oct _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
