Srivatsa S. Bhat <srivatsa.b...@linux.vnet.ibm.com> wrote:
> We can use global rwlocks as shown below safely, without fear of deadlocks:
>
> Readers:
>
> CPU 0 CPU 1
> ------ ------
>
> 1. spin_lock(&random_lock); read_lock(&my_rwlock);
>
>
> 2. read_lock(&my_rwlock); spin_lock(&random_lock);
The lock order on CPU 0 is unsafe if CPU2 can do:
write_lock(&my_rwlock);
spin_lock(&random_lock);
and on CPU 1 if CPU2 can do:
spin_lock(&random_lock);
write_lock(&my_rwlock);
I presume you were specifically excluding these situations?
David
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