static int
nfp_resource_try_acquire(struct nfp_cpp *cpp, struct nfp_resource *res,
struct nfp_cpp_mutex *dev_mutex)
{
int err;
if (nfp_cpp_mutex_lock(dev_mutex))
return -EINVAL;
err = nfp_cpp_resource_find(cpp, res);
if (err)
goto err_unlock_dev;
err = nfp_cpp_mutex_trylock(res->mutex);
if (err)
goto err_res_mutex_free;
nfp_cpp_mutex_unlock(dev_mutex);
return 0;
err_res_mutex_free:
nfp_cpp_mutex_free(res->mutex);
err_unlock_dev:
nfp_cpp_mutex_unlock(dev_mutex);
return err;
}
/**
* nfp_cpp_mutex_lock() - Lock a mutex handle, using the NFP MU Atomic Engine
* @mutex: NFP CPP Mutex handle
*
* Return: 0 on success, or -errno on failure
*/
int nfp_cpp_mutex_lock(struct nfp_cpp_mutex *mutex)
{
unsigned long warn_at = jiffies + NFP_MUTEX_WAIT_FIRST_WARN * HZ;
unsigned long err_at = jiffies + NFP_MUTEX_WAIT_ERROR * HZ;
unsigned int timeout_ms = 1;
int err;
/* We can't use a waitqueue here, because the unlocker
* might be on a separate CPU.
*
* So just wait for now.
*/
for (;;) {
err = nfp_cpp_mutex_trylock(mutex);
if (err != -EBUSY)
break;
err = msleep_interruptible(timeout_ms);
if (err != 0) {
nfp_info(mutex->cpp,
"interrupted waiting for NFP mutex\n");
return -ERESTARTSYS;
}
if (time_is_before_eq_jiffies(warn_at)) {
warn_at = jiffies + NFP_MUTEX_WAIT_NEXT_WARN * HZ;
nfp_warn(mutex->cpp,
"Warning: waiting for NFP mutex [depth:%hd target:%d addr:%llx key:%08x]\n",
mutex->depth,
mutex->target, mutex->address, mutex->key);
}
if (time_is_before_eq_jiffies(err_at)) {
nfp_err(mutex->cpp, "Error: mutex wait timed out\n");
return -EBUSY;
}
}
return err;
}