Commit 17caeaa4 authored by Julian Wiedmann's avatar Julian Wiedmann Committed by David S. Miller
Browse files

s390/qeth: handle skb allocation error gracefully 



When current code fails to allocate an skb in the RX path, it drops the
whole RX buffer. Considering the large number of packets that a single
RX buffer might contain, this is quite drastic.

Skip over the packet instead, and try to extract the next packet from
the RX buffer.

Signed-off-by: default avatarJulian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7d4faee7

drivers/s390/net/qeth_core_main.c

+10 −15
Original line number Diff line number Diff line
@@ -5065,12 +5065,12 @@ struct sk_buff *qeth_core_get_next_skb(struct qeth_card *card, 
	struct qdio_buffer_element *element = *__element;

	struct qdio_buffer *buffer = qethbuffer->buffer;

	int offset = *__offset;

	bool use_rx_sg = false;

	unsigned int headroom;

	struct sk_buff *skb;

	int skb_len = 0;

	void *data_ptr;

	int data_len;

	int headroom = 0;

	int use_rx_sg = 0;



next_packet:

	/* qeth_hdr must not cross element boundaries */
@@ -5086,6 +5086,7 @@ next_packet: 
	switch ((*hdr)->hdr.l2.id) {

	case QETH_HEADER_TYPE_LAYER2:

		skb_len = (*hdr)->hdr.l2.pkt_length;

		headroom = 0;

		break;

	case QETH_HEADER_TYPE_LAYER3:

		skb_len = (*hdr)->hdr.l3.length;
@@ -5120,11 +5121,10 @@ next_packet: 
	if (!skb_len)

		return NULL;



	if (((skb_len >= card->options.rx_sg_cb) &&

	     !IS_OSN(card) &&

	     (!atomic_read(&card->force_alloc_skb))) ||

	    (card->options.cq == QETH_CQ_ENABLED))

		use_rx_sg = 1;

	use_rx_sg = (card->options.cq == QETH_CQ_ENABLED) ||

		    ((skb_len >= card->options.rx_sg_cb) &&

		     !atomic_read(&card->force_alloc_skb) &&

		     !IS_OSN(card));



	if (use_rx_sg && qethbuffer->rx_skb) {

		/* QETH_CQ_ENABLED only: */
@@ -5135,9 +5135,10 @@ next_packet: 


		skb = napi_alloc_skb(&card->napi, linear + headroom);

	}



	if (!skb)

		goto no_mem;

	if (headroom)

		QETH_CARD_STAT_INC(card, rx_dropped_nomem);

	else if (headroom)

		skb_reserve(skb, headroom);



walk_packet:
@@ -5184,12 +5185,6 @@ walk_packet: 
				   skb_shinfo(skb)->nr_frags);

	}

	return skb;

no_mem:

	if (net_ratelimit()) {

		QETH_CARD_TEXT(card, 2, "noskbmem");

	}

	QETH_CARD_STAT_INC(card, rx_dropped_nomem);

	return NULL;

}

EXPORT_SYMBOL_GPL(qeth_core_get_next_skb);

CRA Git | Maintained and supported by SUSTech CRA and CCSE