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Message-ID: <07b59d228048498f75620e9660301006@imap.linux.ibm.com>
Date: Sat, 22 Jan 2022 16:30:55 -0800
From: Dany Madden <drt@...ux.ibm.com>
To: Sukadev Bhattiprolu <sukadev@...ux.ibm.com>
Cc: netdev@...r.kernel.org, Brian King <brking@...ux.ibm.com>,
Rick Lindsley <ricklind@...ux.ibm.com>
Subject: Re: [PATCH net 2/4] ibmvnic: init ->running_cap_crqs early
On 2022-01-21 18:59, Sukadev Bhattiprolu wrote:
> We use ->running_cap_crqs to determine when the ibmvnic_tasklet()
> should
> send out the next protocol message type. i.e when we get back responses
> to all our QUERY_CAPABILITY CRQs we send out REQUEST_CAPABILITY crqs.
> Similiary, when we get responses to all the REQUEST_CAPABILITY crqs, we
> send out the QUERY_IP_OFFLOAD CRQ.
>
> We currently increment ->running_cap_crqs as we send out each CRQ and
> have the ibmvnic_tasklet() send out the next message type, when this
> running_cap_crqs count drops to 0.
>
> This assumes that all the CRQs of the current type were sent out before
> the count drops to 0. However it is possible that we send out say 6
> CRQs,
> get preempted and receive all the 6 responses before we send out the
> remaining CRQs. This can result in ->running_cap_crqs count dropping to
> zero before all messages of the current type were sent and we end up
> sending the next protocol message too early.
>
> Instead initialize the ->running_cap_crqs upfront so the tasklet will
> only send the next protocol message after all responses are received.
>
> Use the cap_reqs local variable to also detect any discrepancy (either
> now or in future) in the number of capability requests we actually
> send.
>
> Currently only send_query_cap() is affected by this behavior (of
> sending
> next message early) since it is called from the worker thread (during
> reset) and from application thread (during ->ndo_open()) and they can
> be
> preempted. send_request_cap() is only called from the tasklet which
> processes CRQ responses sequentially, is not be affected. But to
> maintain the existing symmtery with send_query_capability() we update
> send_request_capability() also.
>
> Fixes: 249168ad07cd ("ibmvnic: Make CRQ interrupt tasklet wait for all
> capabilities crqs")
> Signed-off-by: Sukadev Bhattiprolu <sukadev@...ux.ibm.com>
Reviewed-by: Dany Madden <drt@...ux.ibm.com>
> ---
> drivers/net/ethernet/ibm/ibmvnic.c | 106 +++++++++++++++++++----------
> 1 file changed, 71 insertions(+), 35 deletions(-)
>
>
> diff --git a/drivers/net/ethernet/ibm/ibmvnic.c
> b/drivers/net/ethernet/ibm/ibmvnic.c
> index 9b2d16ad76f1..acd488310bbc 100644
> --- a/drivers/net/ethernet/ibm/ibmvnic.c
> +++ b/drivers/net/ethernet/ibm/ibmvnic.c
> @@ -3849,11 +3849,25 @@ static void send_request_cap(struct
> ibmvnic_adapter *adapter, int retry)
> struct device *dev = &adapter->vdev->dev;
> union ibmvnic_crq crq;
> int max_entries;
> + int cap_reqs;
> +
> + /* We send out 6 or 7 REQUEST_CAPABILITY CRQs below (depending on
> + * the PROMISC flag). Initialize this count upfront. When the tasklet
> + * receives a response to all of these, it will send the next
> protocol
> + * message (QUERY_IP_OFFLOAD).
> + */
> + if (!(adapter->netdev->flags & IFF_PROMISC) ||
> + adapter->promisc_supported)
> + cap_reqs = 7;
> + else
> + cap_reqs = 6;
>
> if (!retry) {
> /* Sub-CRQ entries are 32 byte long */
> int entries_page = 4 * PAGE_SIZE / (sizeof(u64) * 4);
>
> + atomic_set(&adapter->running_cap_crqs, cap_reqs);
> +
> if (adapter->min_tx_entries_per_subcrq > entries_page ||
> adapter->min_rx_add_entries_per_subcrq > entries_page) {
> dev_err(dev, "Fatal, invalid entries per sub-crq\n");
> @@ -3914,44 +3928,45 @@ static void send_request_cap(struct
> ibmvnic_adapter *adapter, int retry)
> adapter->opt_rx_comp_queues;
>
> adapter->req_rx_add_queues = adapter->max_rx_add_queues;
> + } else {
> + atomic_add(cap_reqs, &adapter->running_cap_crqs);
> }
> -
> memset(&crq, 0, sizeof(crq));
> crq.request_capability.first = IBMVNIC_CRQ_CMD;
> crq.request_capability.cmd = REQUEST_CAPABILITY;
>
> crq.request_capability.capability = cpu_to_be16(REQ_TX_QUEUES);
> crq.request_capability.number = cpu_to_be64(adapter->req_tx_queues);
> - atomic_inc(&adapter->running_cap_crqs);
> + cap_reqs--;
> ibmvnic_send_crq(adapter, &crq);
>
> crq.request_capability.capability = cpu_to_be16(REQ_RX_QUEUES);
> crq.request_capability.number = cpu_to_be64(adapter->req_rx_queues);
> - atomic_inc(&adapter->running_cap_crqs);
> + cap_reqs--;
> ibmvnic_send_crq(adapter, &crq);
>
> crq.request_capability.capability = cpu_to_be16(REQ_RX_ADD_QUEUES);
> crq.request_capability.number =
> cpu_to_be64(adapter->req_rx_add_queues);
> - atomic_inc(&adapter->running_cap_crqs);
> + cap_reqs--;
> ibmvnic_send_crq(adapter, &crq);
>
> crq.request_capability.capability =
> cpu_to_be16(REQ_TX_ENTRIES_PER_SUBCRQ);
> crq.request_capability.number =
> cpu_to_be64(adapter->req_tx_entries_per_subcrq);
> - atomic_inc(&adapter->running_cap_crqs);
> + cap_reqs--;
> ibmvnic_send_crq(adapter, &crq);
>
> crq.request_capability.capability =
> cpu_to_be16(REQ_RX_ADD_ENTRIES_PER_SUBCRQ);
> crq.request_capability.number =
> cpu_to_be64(adapter->req_rx_add_entries_per_subcrq);
> - atomic_inc(&adapter->running_cap_crqs);
> + cap_reqs--;
> ibmvnic_send_crq(adapter, &crq);
>
> crq.request_capability.capability = cpu_to_be16(REQ_MTU);
> crq.request_capability.number = cpu_to_be64(adapter->req_mtu);
> - atomic_inc(&adapter->running_cap_crqs);
> + cap_reqs--;
> ibmvnic_send_crq(adapter, &crq);
>
> if (adapter->netdev->flags & IFF_PROMISC) {
> @@ -3959,16 +3974,21 @@ static void send_request_cap(struct
> ibmvnic_adapter *adapter, int retry)
> crq.request_capability.capability =
> cpu_to_be16(PROMISC_REQUESTED);
> crq.request_capability.number = cpu_to_be64(1);
> - atomic_inc(&adapter->running_cap_crqs);
> + cap_reqs--;
> ibmvnic_send_crq(adapter, &crq);
> }
> } else {
> crq.request_capability.capability =
> cpu_to_be16(PROMISC_REQUESTED);
> crq.request_capability.number = cpu_to_be64(0);
> - atomic_inc(&adapter->running_cap_crqs);
> + cap_reqs--;
> ibmvnic_send_crq(adapter, &crq);
> }
> +
> + /* Keep at end to catch any discrepancy between expected and actual
> + * CRQs sent.
> + */
> + WARN_ON(cap_reqs != 0);
> }
>
> static int pending_scrq(struct ibmvnic_adapter *adapter,
> @@ -4362,118 +4382,132 @@ static void send_query_map(struct
> ibmvnic_adapter *adapter)
> static void send_query_cap(struct ibmvnic_adapter *adapter)
> {
> union ibmvnic_crq crq;
> + int cap_reqs;
> +
> + /* We send out 25 QUERY_CAPABILITY CRQs below. Initialize this count
> + * upfront. When the tasklet receives a response to all of these, it
> + * can send out the next protocol messaage (REQUEST_CAPABILITY).
> + */
> + cap_reqs = 25;
> +
> + atomic_set(&adapter->running_cap_crqs, cap_reqs);
>
> - atomic_set(&adapter->running_cap_crqs, 0);
> memset(&crq, 0, sizeof(crq));
> crq.query_capability.first = IBMVNIC_CRQ_CMD;
> crq.query_capability.cmd = QUERY_CAPABILITY;
>
> crq.query_capability.capability = cpu_to_be16(MIN_TX_QUEUES);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(MIN_RX_QUEUES);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(MIN_RX_ADD_QUEUES);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(MAX_TX_QUEUES);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(MAX_RX_QUEUES);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(MAX_RX_ADD_QUEUES);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability =
> cpu_to_be16(MIN_TX_ENTRIES_PER_SUBCRQ);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability =
> cpu_to_be16(MIN_RX_ADD_ENTRIES_PER_SUBCRQ);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability =
> cpu_to_be16(MAX_TX_ENTRIES_PER_SUBCRQ);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability =
> cpu_to_be16(MAX_RX_ADD_ENTRIES_PER_SUBCRQ);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(TCP_IP_OFFLOAD);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(PROMISC_SUPPORTED);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(MIN_MTU);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(MAX_MTU);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(MAX_MULTICAST_FILTERS);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(VLAN_HEADER_INSERTION);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability =
> cpu_to_be16(RX_VLAN_HEADER_INSERTION);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(MAX_TX_SG_ENTRIES);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(RX_SG_SUPPORTED);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability =
> cpu_to_be16(OPT_TX_COMP_SUB_QUEUES);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(OPT_RX_COMP_QUEUES);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability =
> cpu_to_be16(OPT_RX_BUFADD_Q_PER_RX_COMP_Q);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability =
> cpu_to_be16(OPT_TX_ENTRIES_PER_SUBCRQ);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability =
> cpu_to_be16(OPT_RXBA_ENTRIES_PER_SUBCRQ);
> - atomic_inc(&adapter->running_cap_crqs);
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
>
> crq.query_capability.capability = cpu_to_be16(TX_RX_DESC_REQ);
> - atomic_inc(&adapter->running_cap_crqs);
> +
> ibmvnic_send_crq(adapter, &crq);
> + cap_reqs--;
> +
> + /* Keep at end to catch any discrepancy between expected and actual
> + * CRQs sent.
> + */
> + WARN_ON(cap_reqs != 0);
> }
>
> static void send_query_ip_offload(struct ibmvnic_adapter *adapter)
> @@ -4777,6 +4811,8 @@ static void handle_request_cap_rsp(union
> ibmvnic_crq *crq,
> char *name;
>
> atomic_dec(&adapter->running_cap_crqs);
> + netdev_dbg(adapter->netdev, "Outstanding request-caps: %d\n",
> + atomic_read(&adapter->running_cap_crqs));
> switch (be16_to_cpu(crq->request_capability_rsp.capability)) {
> case REQ_TX_QUEUES:
> req_value = &adapter->req_tx_queues;
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