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[POWERPC] spufs: fix invalid scheduling of forgotten contexts 

At present, we have a situation where a context with no owner is
re-scheduled by spu_forget:

	Thread 1: reading regs file	Thread 2: context owner

					spu_forget()
						- ctx->owner = NULL
						- set SPU_SCHED_WAS_ACTIVE

	spu_acquire_saved()
	- context is in saved state

	spu_release_saved()
	- SPU_SCHED_WAS_ACTIVE is set,
	  so spu_activate() the context,
	  which now has no owner

In spu_forget(), we shouldn't be requesting a re-schedule by setting
SPU_SCHED_WAS_ACTIVE. This change removes the set_bit in spu_forget(),
so that spu_release_saved() doesn't reinsert this destroyed context on
to the run queue.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
This commit is contained in:
Jeremy Kerr 2008-02-27 19:08:13 +11:00
parent d58831375d
commit 0111a70186
1 changed files with 3 additions and 4 deletions
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7
arch/powerpc/platforms/cell/spufs/context.c
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@ -109,13 +109,12 @@ void spu_forget(struct spu_context *ctx)
/* /*
* This is basically an open-coded spu_acquire_saved, except that * This is basically an open-coded spu_acquire_saved, except that
* we don't acquire the state mutex interruptible. * we don't acquire the state mutex interruptible, and we don't
* want this context to be rescheduled on release.
*/ */
mutex_lock(&ctx->state_mutex); mutex_lock(&ctx->state_mutex);
if (ctx->state != SPU_STATE_SAVED) { if (ctx->state != SPU_STATE_SAVED)
set_bit(SPU_SCHED_WAS_ACTIVE, &ctx->sched_flags);
spu_deactivate(ctx); spu_deactivate(ctx);
}
mm = ctx->owner; mm = ctx->owner;
ctx->owner = NULL; ctx->owner = NULL;