Commit aa6daaca authored Nov 18, 2018 by Eric Dumazet Committed by David S. Miller Nov 18, 2018

tun: use netdev_alloc_frag() in tun_napi_alloc_frags()



In order to cook skbs in the same way than Ethernet drivers,
it is probably better to not use GFP_KERNEL, but rather
use the GFP_ATOMIC and PFMEMALLOC mechanisms provided by
netdev_alloc_frag().

This would allow to use tun driver even in memory stress
situations, especially if swap is used over this tun channel.

Fixes: 90e33d45 ("tun: enable napi_gro_frags() for TUN/TAP driver")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Petar Penkov <peterpenkov96@gmail.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 05b0e1d6

drivers/net/tun.c

+7 −8

Original line number	Diff line number	Diff line
		@@ -1478,23 +1478,22 @@ static struct sk_buff tun_napi_alloc_frags(struct tun_file tfile,
		skb->truesize += skb->data_len;

		for (i = 1; i < it->nr_segs; i++) {
		struct page_frag *pfrag = &current->task_frag;
		size_t fragsz = it->iov[i].iov_len;
		struct page *page;
		void *frag;

		if (fragsz == 0 \|\| fragsz > PAGE_SIZE) {
		err = -EINVAL;
		goto free;
		}

		if (!skb_page_frag_refill(fragsz, pfrag, GFP_KERNEL)) {
		frag = netdev_alloc_frag(fragsz);
		if (!frag) {
		err = -ENOMEM;
		goto free;
		}

		skb_fill_page_desc(skb, i - 1, pfrag->page,
		pfrag->offset, fragsz);
		page_ref_inc(pfrag->page);
		pfrag->offset += fragsz;
		page = virt_to_head_page(frag);
		skb_fill_page_desc(skb, i - 1, page,
		frag - page_address(page), fragsz);
		}

		return skb;

Admin message