Randy Dunlap wrote:
Jeff Garzik wrote:
Jeremy Fitzhardinge wrote:
No, David means that "asm volatile (...)" is meaningful and OK to use.
I thought it was OK in readl(), writel(), etc... (and in asm),
but that's it. (and jiffies)
In a driver? Highly unlikey it is OK. In a filesystem? Even more
unlikely it is OK to use.
The set of circumstances where 'volatile' is acceptable is very limited.
You will see it used properly in the definitions of writel(), for
example. But most drivers using 'volatile' are likely bugs.
Not sure how to interpret your top-posted response :)
It is normal in the definition of writel(), in arch code, but
inappropriate in drivers when they _use_ writel().
If I may generalize, arch code generally knows what it's doing, when it
uses volatile. OTOH, driver authors that use volatile generally do
/not/ know what they are doing.
Jeff
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