Hacksaw wrote: >What I would expect the kernel to do is this: > >system_call_data_prep (userdata, size){ [...] > for each page from userdata to userdata+size > { > if the page is swapped out, swap it in > if the page is not owned by the user process, return -ENOWAYMAN > otherwise, lock the page > } [...]
One challenge that might make this issue a little tricky is that you have to handle double-indirection, where the kernel copies in a buffer that includes a pointer to some other buffer that you then have to copy in. I think this comes up in some of the ioctl() calls. Because only the guts of the ioctl() implementation knows the format of the data structure, only it knows what system_call_data_prep() calls would be needed. So, everywhere that currently does copy_from_user() would have to do system_call_data_prep(). (It wouldn't be sufficient to call system_call_data_prep() once in some standardized way at the start of each system call, and leave it at that.) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/