Messages in this thread |  | | Date | Thu, 09 Nov 2000 15:27:37 -0500 | From | Brian Gerst <> | Subject | Re: Module open() problems, Linux 2.4.0 |
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"Richard B. Johnson" wrote: > > On Thu, 9 Nov 2000, Brian Gerst wrote: > > > "Richard B. Johnson" wrote: > > > > > > `lsmod` shows that a device is open twice when using Linux-2.4.0-test9 > > > when, in fact, it has been opened only once. > > > > > > > > > > When the module is closed, the use-count goes to zero as expected. > > > However, a single open() causes the use-count to be 2. > > > > This is harmless. It is caused by a try_inc_mod_count(module) in the > > function calling device_open(), which is the proper way for module > > locking to be handled when not holding the BKL. You can keep the > > MOD_INC_USE_COUNT in the device driver for compatability with 2.2. > > > > Brian Gerst > > This may be, as you say, "harmless". It is, however, a bug. The > reporting must be correct or large complex systems can't be > developed or maintained. > > I had two persons, working nearly a week, trying to find out > what one of over 200 processes had a device open when only > one was supposed to have it opened. --Err we have to check > our work here. The fact that something "works" is not > sufficient.
It is not a bug. The only values that matter are zero and non-zero. As long as the refcounting is symmetric, it all comes out in the wash. Remove the MOD_{INC,DEC}_USE_COUNT from your driver if it bothers you that much and you don't care about 2.2 compatability.
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