correct use of lock_kernel() - help! please

Hi,

In the driver I am working on (dmasound) someone has placed lock/unlock
_kernel() pairs around whole functions.

This means that (e.g.) if we release the sound device with a lot of
un-played samples at a low-ish sample rate...

AFACIT we could hold the kernel locked for *several seconds*

What do I really need to protect with lock/unlock pairs?

or am I missing something (it wouldn't be the first time ..) ;-?

ciao,
Iain.

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Hi,

On Mon, 29 Jan 2001, Iain Sandoe wrote:

AFACIT we could hold the kernel locked for *several seconds*

If you sleep inbetween, it's no problem. The kernel lock is released
automatically during sleep and reget after sleeping.

What do I really need to protect with lock/unlock pairs?

SMP protection. Only a single processor can hold the kernel lock at the
same time. The preferred solution is of course to use semaphores /
spinlocks.

bye, Roman


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