[PATCH] spufs: serialize sys_spu_run per spu
During an earlier cleanup, we lost the serialization
of multiple spu_run calls performed on the same
spu_context. In order to get this back, introduce a
mutex in the spu_context that is held inside of spu_run.
Noticed by Al Viro.
Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/platforms/cell/spufs/context.c b/arch/powerpc/platforms/cell/spufs/context.c
index 903c35d..c5cd55a 100644
--- a/arch/powerpc/platforms/cell/spufs/context.c
+++ b/arch/powerpc/platforms/cell/spufs/context.c
@@ -43,6 +43,7 @@
spin_lock_init(&ctx->mmio_lock);
kref_init(&ctx->kref);
init_rwsem(&ctx->state_sema);
+ init_MUTEX(&ctx->run_sema);
init_waitqueue_head(&ctx->ibox_wq);
init_waitqueue_head(&ctx->wbox_wq);
init_waitqueue_head(&ctx->stop_wq);
diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index 9738de7..e634268 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -620,8 +620,12 @@
{
int ret;
- if ((ret = spu_run_init(ctx, npc, status)) != 0)
- return ret;
+ if (down_interruptible(&ctx->run_sema))
+ return -ERESTARTSYS;
+
+ ret = spu_run_init(ctx, npc, status);
+ if (ret)
+ goto out;
do {
ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, status));
@@ -629,9 +633,8 @@
break;
if (unlikely(ctx->state != SPU_STATE_RUNNABLE)) {
ret = spu_reacquire_runnable(ctx, npc, status);
- if (ret) {
- return ret;
- }
+ if (ret)
+ goto out;
continue;
}
ret = spu_process_events(ctx);
@@ -645,6 +648,8 @@
ret = *status;
spu_yield(ctx);
+out:
+ up(&ctx->run_sema);
return ret;
}
diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h
index 420953b..b504744 100644
--- a/arch/powerpc/platforms/cell/spufs/spufs.h
+++ b/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -48,6 +48,7 @@
enum { SPU_STATE_RUNNABLE, SPU_STATE_SAVED } state;
struct rw_semaphore state_sema;
+ struct semaphore run_sema;
struct mm_struct *owner;