Re: [PATCH] mm/hmm: potential deadlock in nonblocking code

[Matthew Wilcox <willy@xxxxxxxxxxxxx>]

On Mon, Feb 04, 2019 at 04:20:44PM +0300, Dan Carpenter wrote:
>  
> -	if (!nrange->blockable && !mutex_trylock(&hmm->lock)) {
> -		ret = -EAGAIN;
> -		goto out;
> +	if (!nrange->blockable) {
> +		if (!mutex_trylock(&hmm->lock)) {
> +			ret = -EAGAIN;
> +			goto out;
> +		}
>  	} else
>  		mutex_lock(&hmm->lock);

I think this would be more readable written as:

	ret = -EAGAIN;
	if (nrange->blockable)
		mutex_lock(&hmm->lock);
	else if (!mutex_trylock(&hmm->lock))
		goto out;

but it'll be up to Jerome.