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authorAndre Detsch <adetsch@br.ibm.com>2008-07-24 10:57:26 +1000
committerJeremy Kerr <jk@ozlabs.org>2008-07-24 10:57:26 +1000
commit0855b543222e79cbbd9d66dd56cb54740e7d524f (patch)
tree77e6e838138d623c96e61c497417e9fc0f82100e /arch/powerpc
parent9bcab8405c98c34849c5795c717b7e6a3e2d3875 (diff)
powerpc/spufs: fix aff_mutex and cbe_spu_info[n].list_mutex deadlock
Currenlt,, it is possible to lock aff_mutex and cbe_spu_info[n].list_mutex in different orders, allowing a deadlock to occur. With this change, aff_mutex is not taken within a list_mutex critical section anymore. Signed-off-by: Andre Detsch <adetsch@br.ibm.com> Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/platforms/cell/spufs/sched.c18
1 files changed, 6 insertions, 12 deletions
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 34654743363..f293963cd85 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -389,6 +389,9 @@ static int has_affinity(struct spu_context *ctx)
if (list_empty(&ctx->aff_list))
return 0;
+ if (atomic_read(&ctx->gang->aff_sched_count) == 0)
+ ctx->gang->aff_ref_spu = NULL;
+
if (!gang->aff_ref_spu) {
if (!(gang->aff_flags & AFF_MERGED))
aff_merge_remaining_ctxs(gang);
@@ -416,14 +419,8 @@ static void spu_unbind_context(struct spu *spu, struct spu_context *ctx)
if (spu->ctx->flags & SPU_CREATE_NOSCHED)
atomic_dec(&cbe_spu_info[spu->node].reserved_spus);
- if (ctx->gang){
- mutex_lock(&ctx->gang->aff_mutex);
- if (has_affinity(ctx)) {
- if (atomic_dec_and_test(&ctx->gang->aff_sched_count))
- ctx->gang->aff_ref_spu = NULL;
- }
- mutex_unlock(&ctx->gang->aff_mutex);
- }
+ if (ctx->gang)
+ atomic_dec_if_positive(&ctx->gang->aff_sched_count);
spu_switch_notify(spu, NULL);
spu_unmap_mappings(ctx);
@@ -562,10 +559,7 @@ static struct spu *spu_get_idle(struct spu_context *ctx)
goto found;
mutex_unlock(&cbe_spu_info[node].list_mutex);
- mutex_lock(&ctx->gang->aff_mutex);
- if (atomic_dec_and_test(&ctx->gang->aff_sched_count))
- ctx->gang->aff_ref_spu = NULL;
- mutex_unlock(&ctx->gang->aff_mutex);
+ atomic_dec(&ctx->gang->aff_sched_count);
goto not_found;
}
mutex_unlock(&ctx->gang->aff_mutex);