From c37d6e3f25cf95cdefaa51eaad699382f34cdd0c Mon Sep 17 00:00:00 2001 From: Shannon Nelson Date: Mon, 6 Jan 2020 19:43:48 -0800 Subject: [PATCH] ionic: restrict received packets to mtu size Make sure the NIC drops packets that are larger than the specified MTU. The front end of the NIC will accept packets larger than MTU and will copy all the data it can to fill up the driver's posted buffers - if the buffers are not long enough the packet will then get dropped. With the Rx SG buffers allocagted as full pages, we are currently setting up more space than MTU size available and end up receiving some packets that are larger than MTU, up to the size of buffers posted. To be sure the NIC doesn't waste our time with oversized packets we need to lie a little in the SG descriptor about how long is the last SG element. At dealloc time, we know the allocation was a page, so the deallocation doesn't care about what length we put in the descriptor. Signed-off-by: Shannon Nelson Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller --- drivers/net/ethernet/pensando/ionic/ionic_txrx.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c index a009bbe9f9be..e452f4242ba0 100644 --- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c +++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c @@ -343,6 +343,8 @@ void ionic_rx_fill(struct ionic_queue *q) struct ionic_rxq_sg_desc *sg_desc; struct ionic_rxq_sg_elem *sg_elem; struct ionic_rxq_desc *desc; + unsigned int remain_len; + unsigned int seg_len; unsigned int nfrags; bool ring_doorbell; unsigned int i, j; @@ -352,6 +354,7 @@ void ionic_rx_fill(struct ionic_queue *q) nfrags = round_up(len, PAGE_SIZE) / PAGE_SIZE; for (i = ionic_q_space_avail(q); i; i--) { + remain_len = len; desc_info = q->head; desc = desc_info->desc; sg_desc = desc_info->sg_desc; @@ -375,7 +378,9 @@ void ionic_rx_fill(struct ionic_queue *q) return; } desc->addr = cpu_to_le64(page_info->dma_addr); - desc->len = cpu_to_le16(PAGE_SIZE); + seg_len = min_t(unsigned int, PAGE_SIZE, len); + desc->len = cpu_to_le16(seg_len); + remain_len -= seg_len; page_info++; /* fill sg descriptors - pages[1..n] */ @@ -391,7 +396,9 @@ void ionic_rx_fill(struct ionic_queue *q) return; } sg_elem->addr = cpu_to_le64(page_info->dma_addr); - sg_elem->len = cpu_to_le16(PAGE_SIZE); + seg_len = min_t(unsigned int, PAGE_SIZE, remain_len); + sg_elem->len = cpu_to_le16(seg_len); + remain_len -= seg_len; page_info++; }