[Cbe-oss-dev] [PATCH] fix recursive spu_acquire() in SPU pagefault handling

[Akinobu Mita]

I got deadlock by recursive spu_acquire():

spufs_run_spu()
spu_process_events()
spu_irq_class_1_bottom()
spu_handle_mm_fault()
handle_mm_fault()
spufs_mem_mmap_nopfn()

This patch resolves the problem by releasing spu_context while 
calling spu_irq_class_1_bottom(). because it may acquire spu_context again.

Signed-off-by: Akinobu Mita <mita at fixstars.com>

---
 arch/powerpc/platforms/cell/spufs/run.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Index: 2.6-git-ps3/arch/powerpc/platforms/cell/spufs/run.c
===================================================================
--- 2.6-git-ps3.orig/arch/powerpc/platforms/cell/spufs/run.c
+++ 2.6-git-ps3/arch/powerpc/platforms/cell/spufs/run.c
@@ -295,8 +295,11 @@ static inline int spu_process_events(str
 	u64 pte_fault = MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED;
 	int ret = 0;
 
-	if (spu->dsisr & pte_fault)
+	if (spu->dsisr & pte_fault) {
+		spu_release(ctx);
 		ret = spu_irq_class_1_bottom(spu);
+		spu_acquire(ctx);
+	}
 	if (spu->class_0_pending)
 		ret = spu_irq_class_0_bottom(spu);
 	if (!ret && signal_pending(current))