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Re: CVS commit: src/sys/opencrypto

On Fri, 24 Jan 2014, Taylor R Campbell wrote:

Shouldn't devsw_detach or config_fini_component handle this?  Why does
the crypto device need special reference counting that other devices

The crypto device isn't special in this regard. Pretty much all device driver modules need this sort of ref-counting. Without it, the race exists and at some future time something will have reused/overwritten the memory previously occupied by the module, with non-deterministic results.

Crypto is special only in that it tried to do some clean-up during the detach. The pool_destroy() code correctly noticed that there were still some outstanding allocations that had not been returned. So we sort of "got lucky" here and found out about the problem immediately, rather than waiting for some non-deterministic future.

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