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    SubjectRe: [PATCH] fix pktcdvd breakage from commit e105b8bfc769b0545b6f0f395179d1e43cbee822
    On Sun, Nov 30, 2008 at 14:21, Al Viro <> wrote:
    > On Sun, Nov 30, 2008 at 01:41:29PM +0100, Kay Sievers wrote:
    >> I posted a fix for that weeks ago. But the pktcdvd maintainer stated,
    >> that the char device nodes are not used for anything. So the whole use
    >> of dev_t should be removed entirely. They just blindly claim the same
    >> char dev_t the block devices use, and conflict with char devices from
    >> other subsystems. Patching out the /sys/dev/class links fixes the
    >> oops, but the underlying fundamental breakage will still exist.
    >> Original mail here states:
    >> "Maybe, but that character device would not be used for anything,
    >> besides creating sub-directories in /sys/class/pktcdvd. The driver
    >> implements a block device, not a character device."
    > _What_ character device nodes? The only thing that dev_t value used to
    > be used for was giving contents for a text file - ..../dev in sysfs directory.
    > With introduction of /sys/dev/char the damn thing got confused for
    > character device number *by* *device_create()*. That's all.
    > There are no character device nodes at all. Driver doesn't claim them.
    > Not in that call of device_create(), not anywhere else. sysfs doesn't
    > create them (or any other device nodes). If you mknod such thing as
    > char device and try to open it, the kernel won't go anywhere near this driver,
    > whether there'd been other drivers or not.
    > So what kind of fundamental breakage are you talking about? All I can see
    > here is a bogus entry added to bogu^Wmisguided^W /sys/dev/char, which leads
    > to WARN_ON() in case if somebody had char device with device number numerically
    > equal to that of our block device and to silent crapping into /sys/dev/char
    > if no such char device had been there already

    Pktcdvd creates char _and_ block device nodes at the same time, while
    the char nodes are not allocated, but created and conflict in
    /sys/dev/ with properly allocated ones from other subsystems. Your
    patch just papers over this bug.


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      Last update: 2008-11-30 14:29    [W:0.022 / U:35.976 seconds]
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