I'm writting a network driver for a DMA-enabled Fast Ethernet card, for linux 2.4. If I'm not mistaken, whenever it wants to transmit a packet, the kernel calls the driver's "hard_start_xmit()" function, passing it a pointer to the "skb" holding the packet. My question is: is there any guarantee that the packet's data at "skb->data" are stored in physically continuous memory locations? If it is so, then I can pass the "skb->data" pointer (using of-course "pci_map_single()", in order to synchronize it, and get its physical address) directly to the card and let it do all the work. Existing drivers I've studied (namely: "eepro100.c") seem to make this assumption, but I have also heard that "zero-copy" networking was added to the kernel at some point. This indicates that, since data come directly for user-space, they might be non-continuous. What really goes on? Thanks in advance /npat -- That's right. Being a kernel maintainer suddenly turns your sex appeal up by about 1000% for some magic reason. -- Linus -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
