Re: spin_lock and linux philosophy question...

Stephen C. Tweedie (sct@redhat.com)
Tue, 14 Sep 1999 17:08:26 +0100 (BST)


Hi,

On Mon, 13 Sep 1999 07:01:41 -0700 (PDT), Robert Dinse
<nanook@eskimo.com> said:

> Are there ever cases where you lock outside of interrupts but
> expect code inside of an interrupt handler to unlock? Or
> conversely, cases where you lock during an interrupt, do some
> preliminary work, then return expecting code outside to unlock?

For IO it is very common: we lock a page or a buffer_head before
submitting the IO, and the interrupt unlocks it afterwards. This is
always the blocking, wait-queue based type of locking, though: we
never do this with spinlocks.

--Stephen

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