From bd28df26197b2bd0913bf1b36770836481975143 Mon Sep 17 00:00:00 2001 From: Aleksandr Mishin Date: Thu, 17 Oct 2024 13:06:50 +0300 Subject: octeon_ep: Implement helper for iterating packets in Rx queue The common code with some packet and index manipulations is extracted and moved to newly implemented helper to make the code more readable and avoid duplication. This is a preparation for skb allocation failure handling. Found by Linux Verification Center (linuxtesting.org) with SVACE. Suggested-by: Simon Horman Suggested-by: Paolo Abeni Signed-off-by: Aleksandr Mishin Reviewed-by: Jacob Keller Signed-off-by: Andrew Lunn --- drivers/net/ethernet/marvell/octeon_ep/octep_rx.c | 55 +++++++++++++---------- 1 file changed, 32 insertions(+), 23 deletions(-) (limited to 'drivers/net/ethernet/marvell/octeon_ep/octep_rx.c') diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c b/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c index 4746a6b258f0..a889c1510518 100644 --- a/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c +++ b/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c @@ -336,6 +336,30 @@ static int octep_oq_check_hw_for_pkts(struct octep_device *oct, return new_pkts; } +/** + * octep_oq_next_pkt() - Move to the next packet in Rx queue. + * + * @oq: Octeon Rx queue data structure. + * @buff_info: Current packet buffer info. + * @read_idx: Current packet index in the ring. + * @desc_used: Current packet descriptor number. + * + * Free the resources associated with a packet. + * Increment packet index in the ring and packet descriptor number. + */ +static void octep_oq_next_pkt(struct octep_oq *oq, + struct octep_rx_buffer *buff_info, + u32 *read_idx, u32 *desc_used) +{ + dma_unmap_page(oq->dev, oq->desc_ring[*read_idx].buffer_ptr, + PAGE_SIZE, DMA_FROM_DEVICE); + buff_info->page = NULL; + (*read_idx)++; + (*desc_used)++; + if (*read_idx == oq->max_count) + *read_idx = 0; +} + /** * __octep_oq_process_rx() - Process hardware Rx queue and push to stack. * @@ -367,10 +391,7 @@ static int __octep_oq_process_rx(struct octep_device *oct, desc_used = 0; for (pkt = 0; pkt < pkts_to_process; pkt++) { buff_info = (struct octep_rx_buffer *)&oq->buff_info[read_idx]; - dma_unmap_page(oq->dev, oq->desc_ring[read_idx].buffer_ptr, - PAGE_SIZE, DMA_FROM_DEVICE); resp_hw = page_address(buff_info->page); - buff_info->page = NULL; /* Swap the length field that is in Big-Endian to CPU */ buff_info->len = be64_to_cpu(resp_hw->length); @@ -394,36 +415,27 @@ static int __octep_oq_process_rx(struct octep_device *oct, data_offset = OCTEP_OQ_RESP_HW_SIZE; rx_ol_flags = 0; } + + octep_oq_next_pkt(oq, buff_info, &read_idx, &desc_used); + + skb = build_skb((void *)resp_hw, PAGE_SIZE); + skb_reserve(skb, data_offset); + rx_bytes += buff_info->len; if (buff_info->len <= oq->max_single_buffer_size) { - skb = build_skb((void *)resp_hw, PAGE_SIZE); - skb_reserve(skb, data_offset); skb_put(skb, buff_info->len); - read_idx++; - desc_used++; - if (read_idx == oq->max_count) - read_idx = 0; } else { struct skb_shared_info *shinfo; u16 data_len; - skb = build_skb((void *)resp_hw, PAGE_SIZE); - skb_reserve(skb, data_offset); /* Head fragment includes response header(s); * subsequent fragments contains only data. */ skb_put(skb, oq->max_single_buffer_size); - read_idx++; - desc_used++; - if (read_idx == oq->max_count) - read_idx = 0; - shinfo = skb_shinfo(skb); data_len = buff_info->len - oq->max_single_buffer_size; while (data_len) { - dma_unmap_page(oq->dev, oq->desc_ring[read_idx].buffer_ptr, - PAGE_SIZE, DMA_FROM_DEVICE); buff_info = (struct octep_rx_buffer *) &oq->buff_info[read_idx]; if (data_len < oq->buffer_size) { @@ -438,11 +450,8 @@ static int __octep_oq_process_rx(struct octep_device *oct, buff_info->page, 0, buff_info->len, buff_info->len); - buff_info->page = NULL; - read_idx++; - desc_used++; - if (read_idx == oq->max_count) - read_idx = 0; + + octep_oq_next_pkt(oq, buff_info, &read_idx, &desc_used); } } -- cgit v1.2.3-70-g09d2 From eb592008f79be52ccef88cd9a5249b3fc0367278 Mon Sep 17 00:00:00 2001 From: Aleksandr Mishin Date: Thu, 17 Oct 2024 13:06:51 +0300 Subject: octeon_ep: Add SKB allocation failures handling in __octep_oq_process_rx() build_skb() returns NULL in case of a memory allocation failure so handle it inside __octep_oq_process_rx() to avoid NULL pointer dereference. __octep_oq_process_rx() is called during NAPI polling by the driver. If skb allocation fails, keep on pulling packets out of the Rx DMA queue: we shouldn't break the polling immediately and thus falsely indicate to the octep_napi_poll() that the Rx pressure is going down. As there is no associated skb in this case, don't process the packets and don't push them up the network stack - they are skipped. Helper function is implemented to unmmap/flush all the fragment buffers used by the dropped packet. 'alloc_failures' counter is incremented to mark the skb allocation error in driver statistics. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 37d79d059606 ("octeon_ep: add Tx/Rx processing and interrupt support") Suggested-by: Paolo Abeni Signed-off-by: Aleksandr Mishin Reviewed-by: Jacob Keller Signed-off-by: Andrew Lunn --- drivers/net/ethernet/marvell/octeon_ep/octep_rx.c | 27 +++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'drivers/net/ethernet/marvell/octeon_ep/octep_rx.c') diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c b/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c index a889c1510518..8af75cb37c3e 100644 --- a/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c +++ b/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c @@ -360,6 +360,27 @@ static void octep_oq_next_pkt(struct octep_oq *oq, *read_idx = 0; } +/** + * octep_oq_drop_rx() - Free the resources associated with a packet. + * + * @oq: Octeon Rx queue data structure. + * @buff_info: Current packet buffer info. + * @read_idx: Current packet index in the ring. + * @desc_used: Current packet descriptor number. + * + */ +static void octep_oq_drop_rx(struct octep_oq *oq, + struct octep_rx_buffer *buff_info, + u32 *read_idx, u32 *desc_used) +{ + int data_len = buff_info->len - oq->max_single_buffer_size; + + while (data_len > 0) { + octep_oq_next_pkt(oq, buff_info, read_idx, desc_used); + data_len -= oq->buffer_size; + }; +} + /** * __octep_oq_process_rx() - Process hardware Rx queue and push to stack. * @@ -419,6 +440,12 @@ static int __octep_oq_process_rx(struct octep_device *oct, octep_oq_next_pkt(oq, buff_info, &read_idx, &desc_used); skb = build_skb((void *)resp_hw, PAGE_SIZE); + if (!skb) { + octep_oq_drop_rx(oq, buff_info, + &read_idx, &desc_used); + oq->stats.alloc_failures++; + continue; + } skb_reserve(skb, data_offset); rx_bytes += buff_info->len; -- cgit v1.2.3-70-g09d2