Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: lseek() on debugfs entries in 2.6.37 | Date | Tue, 15 Mar 2011 15:01:41 +0100 |
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On Tuesday 15 March 2011, Alexey Mikhailov wrote: > I use simple debugfs entries for user-space <-> kernel-space > interaction. Basically I read unsigned integers from debugfs > files like this: > > ... > char buf[64]; > lseek(timesync_fd, 0, SEEK_SET); > read(timesync_fd, buf, sizeof(buf)); > ... > > It works perfectly with 2.6.32 kernel. But with 2.6.37 kernel, > lseek() fails with errno=29(Illegal seek). So second read() > call just fails or returns garbage. Can someone please shed > some light on it?
This is probably a result of the changes I made as part of the BKL removal. Which file specifically are you talking about?
In older kernels, having no .llseek function meant that you implicitly get default_llseek. New kernels now require that the driver explicitly chooses one llseek variant.
I did a patch to automatically convert all drivers, but this patch may have missed some that got moved around while I was patching them.
Arnd
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