powerpc/spufs: Fix possible scheduling of a context to multiple SPEs

We currently have a race when scheduling a context to a SPE -
after we have found a runnable context in spusched_tick, the same
context may have been scheduled by spu_activate().

This may result in a panic if we try to unschedule a context that has
been freed in the meantime.

This change exits spu_schedule() if the context has already been
scheduled, so we don't end up scheduling it twice.

Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
This commit is contained in:
Andre Detsch 2008-09-04 21:16:27 +00:00 committed by Jeremy Kerr
parent b65fe0356b
commit b2e601d14d

View File

@ -728,7 +728,8 @@ static void spu_schedule(struct spu *spu, struct spu_context *ctx)
/* not a candidate for interruptible because it's called either
from the scheduler thread or from spu_deactivate */
mutex_lock(&ctx->state_mutex);
__spu_schedule(spu, ctx);
if (ctx->state == SPU_STATE_SAVED)
__spu_schedule(spu, ctx);
spu_release(ctx);
}