[POWERPC] spufs: Fix race condition on gang->aff_ref_spu
authorAndre Detsch <adetsch@br.ibm.com>
Wed, 19 Sep 2007 04:38:12 +0000 (14:38 +1000)
committerPaul Mackerras <paulus@samba.org>
Wed, 19 Sep 2007 05:12:16 +0000 (15:12 +1000)
commit36ddbb1380f282b4280c57efdb646dd8647a789f
treefbae61d4f858f31ef41631f54d2ab3982f02efb4
parent8b0d3121a0b2cf91768ecef635e241b6abc3f1da
[POWERPC] spufs: Fix race condition on gang->aff_ref_spu

Affinity reference point location (gang->aff_ref_spu) is reset
when the whole gang is descheduled. However, the last member of
a gang can be descheduled while we are trying to schedule another
member of the gang. This was leading to a race condition, and
the code was using gang->aff_ref_spu in an unsafe manner.

By holding the gang->aff_mutex a little bit longer, and increment
gang->aff_sched_count (which controls when gang->aff_ref_spu
should be reset) a little bit earlier, the problem is fixed.

Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
arch/powerpc/platforms/cell/spufs/sched.c