int spu_acquire_runnable(struct spu_context *ctx)
{
int ret = 0;
down_read(&ctx->state_sema);
if (ctx->state == SPU_STATE_RUNNABLE) {
ctx->spu->prio = current->prio;
return 0;
}
up_read(&ctx->state_sema);
down_write(&ctx->state_sema);
/* ctx is about to be freed, can't acquire any more */
if (!ctx->owner) {
ret = -EINVAL;
goto out;
}
if (ctx->state == SPU_STATE_SAVED) {
ret = spu_activate(ctx, 0);
if (ret)
goto out;
ctx->state = SPU_STATE_RUNNABLE;
}
downgrade_write(&ctx->state_sema);
/* On success, we return holding the lock */
return ret;
out:
/* Release here, to simplify calling code. */
up_write(&ctx->state_sema);
return ret;
}
/**
* spu_acquire_exclusive - lock spu contex and protect against userspace access
* @ctx: spu contex to lock
*
* Note:
* Returns 0 and with the context locked on success
* Returns negative error and with the context _unlocked_ on failure.
*/
int spu_acquire_exclusive(struct spu_context *ctx)
{
int ret = -EINVAL;
spu_acquire(ctx);
/*
* Context is about to be freed, so we can't acquire it anymore.
*/
if (!ctx->owner)
goto out_unlock;
if (ctx->state == SPU_STATE_SAVED) {
ret = spu_activate(ctx, 0);
if (ret)
goto out_unlock;
} else {
/*
* We need to exclude userspace access to the context.
*
* To protect against memory access we invalidate all ptes
* and make sure the pagefault handlers block on the mutex.
*/
spu_unmap_mappings(ctx);
}
return 0;
out_unlock:
spu_release(ctx);
return ret;
}
/**
* spu_release_saved - unlock spu context and return it to the runqueue
* @ctx: context to unlock
*/
void spu_release_saved(struct spu_context *ctx)
{
BUG_ON(ctx->state != SPU_STATE_SAVED);
if (test_and_clear_bit(SPU_SCHED_WAS_ACTIVE, &ctx->sched_flags) &&
test_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags))
spu_activate(ctx, 0);
spu_release(ctx);
}
/**
* spu_acquire_runnable - lock spu contex and make sure it is in runnable state
* @ctx: spu contex to lock
*
* Note:
* Returns 0 and with the context locked on success
* Returns negative error and with the context _unlocked_ on failure.
*/
int spu_acquire_runnable(struct spu_context *ctx, unsigned long flags)
{
int ret = -EINVAL;
spu_acquire(ctx);
if (ctx->state == SPU_STATE_SAVED) {
/*
* Context is about to be freed, so we can't acquire it anymore.
*/
if (!ctx->owner)
goto out_unlock;
ret = spu_activate(ctx, flags);
if (ret)
goto out_unlock;
}
return 0;
out_unlock:
spu_release(ctx);
return ret;
}
