On Wed, 2009-10-07 at 14:06 +0800, vichy wrote: > Dear all: > I try to pass the content of file,1G, to kernel driver for operation How? With which sys-calls? > and then return the result back to application. > My questions are: > 1. The only way I can use is copy_from_user? If so, does it have the > size limitation? Not really. Even if, you can call it several times (for different parts of the data) anyways. > 2. I don't want my application pending on the I/O and is there any > smart way to let the application know when driver finishes its job? > appreciate your help, Depends on the sys-calls: - you could use read(2) and write(2): Which has the feature that the user-space app could write chunks of it and the kernel driver can process that immediately (e.g. for compressing the data or similar). The user-space app would block on the read(2) for the result. - you could use an ioctl() which blocks and returns after the driver is done (and you can/should use the same buffer for passing data and receiving it). - you could use two ioctl()s - one for passing data to the kernel, another for blocking and getting it back. Additionally (and indepently) you can send SIGIO (or some other signal?) to the process^Wfile-descriptor to inform the process(es)that the driver is done. Bernd -- Firmix Software GmbH http://www.firmix.at/ mobil: +43 664 4416156 fax: +43 1 7890849-55 Embedded Linux Development and Services -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
