[NCLUG] serialization question

[Larry Butler]

Hello all,

I have some questions that I hope you can answer w.r.t.  char device drivers 
in 2.4.  I'm a bit rusty.  Much has changed since 2.0 when I last did this 
kind of stuff.

First, I'm looking at some code that suggests that calls to open and release 
are serialized in a given driver.  Please confirm or deny.

Second, if I deny multiple openers and don't sleep in write or ioctl, can I 
expect that calls to write and ioctl to be serialized?  I would expect not 
(even with the restriction on multiple openers) since a process can fork and 
its child could write while the parent is writing.  However, I have at least 
one example of code that does some pretty involved poking at hardware without 
any precautions.

Third, where in the Rubini book are the answers?  I must be blind.  I can't 
find them.

Thanks,
Larry