[PATCH 0/3] char: misc: assign file->private_data to miscdevice on open

From: Martin Kepplinger
Date: Wed Oct 29 2014 - 15:25:09 EST


This slightly changes the behaviour of miscdevice drivers at an open()
syscall. Not only if the driver happens to implement an open() fop itself,
but now just always file->private_data points to struct miscdevice, when
a user opens the device file.

This call for review once more: if anybody has an hour to kill:

Look for the only dangerous situation where a miscdevice driver _depends_ on
file->private_data being NULL when _not_ implementing an open() routine
itself. I didn't find anything.

The one section I was unsure about should be ok, see
http://marc.info/?l=linux-kernel&m=141376535132316&w=2

Bonus: one could look for drivers that _do_ implement open()
and do the (in any case) redundant work themselves.

Martin Kepplinger (3):
misc: always assign miscdevice to file->private_data in open()
fbdev: pxa3xx-gcu: remove redundant implementation of open()
char: misc: document behaviour of open()

drivers/char/misc.c | 6 ++++--
drivers/video/fbdev/pxa3xx-gcu.c | 10 ----------
2 files changed, 4 insertions(+), 12 deletions(-)

--
1.7.10.4

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