[PATCH] nvme-tcp: fix memory leak when freeing a queue

[Sagi Grimberg]

> Release the page frag cache when tearing down the io queues
> 
> Signed-off-by: Maurizio Lombardi <mlombard at redhat.com>
> ---
>   drivers/nvme/host/tcp.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
> index 07156ea9d1a8..999417626b15 100644
> --- a/drivers/nvme/host/tcp.c
> +++ b/drivers/nvme/host/tcp.c
> @@ -1229,6 +1229,7 @@ static int nvme_tcp_alloc_async_req(struct nvme_tcp_ctrl *ctrl)
>   
>   static void nvme_tcp_free_queue(struct nvme_ctrl *nctrl, int qid)
>   {
> +	struct page *page;
>   	struct nvme_tcp_ctrl *ctrl = to_tcp_ctrl(nctrl);
>   	struct nvme_tcp_queue *queue = &ctrl->queues[qid];
>   
> @@ -1238,6 +1239,11 @@ static void nvme_tcp_free_queue(struct nvme_ctrl *nctrl, int qid)
>   	if (queue->hdr_digest || queue->data_digest)
>   		nvme_tcp_free_crypto(queue);
>   
> +	if (queue->pf_cache.va) {
> +		page = virt_to_head_page(queue->pf_cache.va);
> +		__page_frag_cache_drain(page, queue->pf_cache.pagecnt_bias);
> +		queue->pf_cache.va = NULL;
> +	}

Thanks Maurizio,

Why do we need to the pf_cache.va protection? nvme_tcp_free_queue
is already protected against re-entry with the NVME_TCP_Q_ALLOCATED
bit.