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    SubjectRe: [PATCH 4/4] ->compat_ioctl for 390 tape_char
    On Sünnavend 05 November 2005 00:51, Christoph Hellwig wrote:
    > we return -ENOIOCTLCMD if we didn't have a valid compat ioctl, and in
    > that case the vfs code will try to find it in the core translation
    > table.

    No, the function you wrote returns -ENOIOCTLCMD only if
    device->discipline->ioctl_fn is NULL, otherwise it returns the
    code it gets from that function, which is -EINVAL.

    > I'm not sure moving everything from fs/compat_ioctl.c is a good idea.
    > Everything that is just in a single driver or subsystem that has
    > common ioctl code - sure.  else it doesn't make a lot of sense.

    It turns out that almost everything is a single driver, the exceptions

    - tty ioctls: I move the conversion into drivers/char/tty_io.c with a
    relatively big switch() statement. All drivers implementing these
    use tty_operations.
    - block ioctl: similar for drivers/block/ioctl.c
    - net ioctl: similar for net/compat.c. I also add compat_ioctl methods
    for proto_ops.
    - cdrom, tape, v4l: I create a new file that contains a compat_ioctl
    file operation that can be used in each driver, either by pointing
    directly to it or by calling it from their own compat_ioctl
    handler. The handlers end up calling f_op->ioctl() internally.
    - file systems: many file systems implement EXT2_IOC_GETFLAGS etc.
    those are trivial to handle, so I duplicate the code for each of those
    file systems.

    Arnd <><
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      Last update: 2005-11-05 02:18    [W:0.021 / U:11.144 seconds]
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