Messages in this thread | | | Subject | Re: Kernel hacking ? - Can this be done? | From | Arjan van de Ven <> | Date | Fri, 30 Jul 1999 22:40:46 +0200 |
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In article <19990730200645.A351@loth.demon.co.uk> you wrote: > On Fri, Jul 30, 1999 at 08:31:44AM +0200, Arjan van de Ven wrote:
>> SK> sys_read calls the the filesystem's read function, which uses >> SK> copy_to_user (since it assumes it is invoked from user space through >> SK> a system call). >> >> See the "set_fs" stuff in kHTTPd.
> Does that mean you're doing a kernel space -> kernel space copy?
Yes.
> Couldn't you just nick the data straight from the page cache?
That is possible too, in fact, I am adding this to kHTTPd right now. For non-performance critical tasks, this is WAY to much pain though, since this will only work for most filesystems (the f_ops->read works for ALL sane filesystems), and proper locking isn't easy either.
Greetings, Arjan van de Ven
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