tree 3ef01b47fc413a5ddb64d46d8ec18e92c65c9e25
parent 4705e02498d6d5a7ab98dfee9595cd5e91db2017
author Michael Neuling <mikey@neuling.org> 1461301068 +1000
committer Michael Ellerman <mpe@ellerman.id.au> 1461722671 +1000

cxl: Keep IRQ mappings on context teardown

Keep IRQ mappings on context teardown.  This won't leak IRQs as if we
allocate the mapping again, the generic code will give the same
mapping used last time.

Doing this works around a race in the generic code. Masking the
interrupt introduces a race which can crash the kernel or result in
IRQ that is never EOIed. The lost of EOI results in all subsequent
mappings to the same HW IRQ never receiving an interrupt.

We've seen this race with cxl test cases which are doing heavy context
startup and teardown at the same time as heavy interrupt load.

A fix to the generic code is being investigated also.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: stable@vger.kernel.org # 3.8
Tested-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Tested-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>