The RX buffer layout depends on the MTU, so changing it rebuilds the queues. Convert mana_change_mtu() to pre-allocate and swap.
The MTU becomes part of the queue-set configuration, so a new set can be built for the new MTU while the running one still serves traffic at the old one, and ndev->mtu is updated only once the new set is live. Previously it was written before mana_attach() and rolled back on failure, so a failed change was briefly visible to the stack. Signed-off-by: Long Li <[email protected]> --- drivers/net/ethernet/microsoft/mana/mana_en.c | 69 ++++++++++++++----- .../ethernet/microsoft/mana/mana_ethtool.c | 8 ++- include/net/mana/mana.h | 13 +++- 3 files changed, 67 insertions(+), 23 deletions(-) diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c index c0f31b386536a34af338c4d8be50537e2fe55317..c858a58577dfb1774b2b9394c01e9000edbe8bf9 100644 --- a/drivers/net/ethernet/microsoft/mana/mana_en.c +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c @@ -884,35 +884,49 @@ int mana_pre_alloc_rxbufs(struct mana_port_context *mpc, int new_mtu, int num_qu return -ENOMEM; } +/* ndev->mtu is updated only once the new set is live (mana_publish_qset), so + * a failed allocation leaves the queues and the advertised MTU untouched. + */ static int mana_change_mtu(struct net_device *ndev, int new_mtu) { struct mana_port_context *mpc = netdev_priv(ndev); - unsigned int old_mtu = ndev->mtu; + struct mana_port_context *scratch; + struct mana_qset newq, oldq; int err; - /* Pre-allocate buffers to prevent failure in mana_attach later */ - err = mana_pre_alloc_rxbufs(mpc, new_mtu, mpc->num_queues); - if (err) { - netdev_err(ndev, "Insufficient memory for new MTU\n"); - return err; + /* Port is down: no queues to rebuild, just record the new MTU. + * mana_open() will size the RX buffers accordingly. + */ + if (!mpc->port_is_up) { + mpc->configured_mtu = new_mtu; + WRITE_ONCE(ndev->mtu, new_mtu); + return 0; } - err = mana_detach(ndev, false); - if (err) { - netdev_err(ndev, "mana_detach failed: %d\n", err); - goto out; - } + scratch = mana_qset_scratch_alloc(mpc); + if (!scratch) + return -ENOMEM; - WRITE_ONCE(ndev->mtu, new_mtu); + err = mana_alloc_qset(scratch, mpc->num_queues, mpc->rx_queue_size, + mpc->tx_queue_size, mpc->priv_flags, new_mtu, + &newq); + if (err) + goto free_scratch; /* current qset and ndev->mtu untouched */ - err = mana_attach(ndev); + err = mana_publish_qset(mpc, &newq, &oldq); if (err) { - netdev_err(ndev, "mana_attach failed: %d\n", err); - WRITE_ONCE(ndev->mtu, old_mtu); + mana_free_qset(scratch, &newq); + goto free_scratch; } -out: - mana_pre_dealloc_rxbufs(mpc); + mana_free_qset(scratch, &oldq); + +free_scratch: + /* After the caller-side cleanup above, so the EQ pool outlives the + * CQs that reference it. + */ + mana_publish_close_if_needed(mpc); + mana_qset_scratch_free(scratch); return err; } @@ -3089,7 +3103,8 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc, rxq->rxq_idx = rxq_idx; rxq->rxobj = INVALID_MANA_HANDLE; - mana_get_rxbuf_cfg(apc, ndev->mtu, &rxq->datasize, &rxq->alloc_size, + mana_get_rxbuf_cfg(apc, apc->configured_mtu, &rxq->datasize, + &rxq->alloc_size, &rxq->headroom, &rxq->frag_count); /* Create page pool for RX queue */ err = mana_create_page_pool(rxq, gc); @@ -3928,6 +3943,7 @@ static void mana_qset_snapshot(const struct mana_port_context *ctx, out->rx_queue_size = ctx->rx_queue_size; out->tx_queue_size = ctx->tx_queue_size; out->priv_flags = ctx->priv_flags; + out->mtu = ctx->configured_mtu; out->mana_eqs_debugfs = ctx->mana_eqs_debugfs; } @@ -3949,6 +3965,7 @@ static void mana_qset_install(struct mana_port_context *ctx, ctx->rx_queue_size = qset->rx_queue_size; ctx->tx_queue_size = qset->tx_queue_size; ctx->priv_flags = qset->priv_flags; + ctx->configured_mtu = qset->mtu; ctx->mana_eqs_debugfs = qset->mana_eqs_debugfs; } @@ -4011,7 +4028,7 @@ void mana_qset_scratch_free(struct mana_port_context *scratch) */ int mana_alloc_qset(struct mana_port_context *scratch, unsigned int num_queues, unsigned int rx_queue_size, unsigned int tx_queue_size, - u32 priv_flags, struct mana_qset *out) + u32 priv_flags, int mtu, struct mana_qset *out) { struct net_device *ndev = scratch->ndev; int err; @@ -4023,6 +4040,12 @@ int mana_alloc_qset(struct mana_port_context *scratch, unsigned int num_queues, scratch->tx_queue_size = tx_queue_size; scratch->priv_flags = priv_flags; + /* mana_get_rxbuf_cfg() reads this when sizing RX buffers, so the + * new set is built for the requested MTU without disturbing the + * running set. + */ + scratch->configured_mtu = mtu; + err = mana_init_port_context(scratch); if (err) goto out_err; @@ -4237,6 +4260,11 @@ int mana_publish_qset(struct mana_port_context *apc, struct mana_qset *newq, if (err) goto rollback; + /* The new set is serving traffic, so advertise its MTU. A no-op unless + * the caller is changing it. + */ + WRITE_ONCE(ndev->mtu, apc->configured_mtu); + /* Pair with the queue-state stores above: a datapath reader that sees * the gate open must also see the queue set it is about to index. */ @@ -4289,6 +4317,8 @@ int mana_publish_qset(struct mana_port_context *apc, struct mana_qset *newq, return err; } + WRITE_ONCE(ndev->mtu, apc->configured_mtu); + /* Same pairing as the success path: the restored queue set has to be * visible before the gate reopens on it. */ @@ -4508,6 +4538,7 @@ static int mana_probe_port(struct mana_context *ac, int port_idx, apc->port_handle = INVALID_MANA_HANDLE; apc->pf_filter_handle = INVALID_MANA_HANDLE; apc->port_idx = port_idx; + apc->configured_mtu = ndev->mtu; apc->link_cfg_error = 1; apc->cqe_coalescing_enable = 0; apc->cqe8_coalescing_enable = 0; diff --git a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c index dc3a0a22959ef19e2ea9921e81c7295aef628ccf..f4818305bec83f8a60ce02baf280b0d4b9fcb51e 100644 --- a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c +++ b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c @@ -723,7 +723,8 @@ static int mana_set_channels(struct net_device *ndev, } err = mana_alloc_qset(scratch, new_count, apc->rx_queue_size, - apc->tx_queue_size, apc->priv_flags, &newq); + apc->tx_queue_size, apc->priv_flags, + apc->configured_mtu, &newq); if (err) goto free_scratch; /* current qset untouched, nothing to undo */ @@ -818,7 +819,7 @@ static int mana_set_ringparam(struct net_device *ndev, } err = mana_alloc_qset(scratch, apc->num_queues, new_rx, new_tx, - apc->priv_flags, &newq); + apc->priv_flags, apc->configured_mtu, &newq); if (err) { NL_SET_ERR_MSG_FMT(extack, "failed to change ring params: %d", err); @@ -916,7 +917,8 @@ static int mana_set_priv_flags(struct net_device *ndev, u32 priv_flags) } err = mana_alloc_qset(scratch, apc->num_queues, apc->rx_queue_size, - apc->tx_queue_size, priv_flags, &newq); + apc->tx_queue_size, priv_flags, + apc->configured_mtu, &newq); if (err) goto free_scratch; /* current qset and priv_flags untouched */ diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h index 66a653bad22eba511d8cf8cf71b572c604044ecb..b9d79240dbc7cc0fb106336d68b6f0cf3a34f2bf 100644 --- a/include/net/mana/mana.h +++ b/include/net/mana/mana.h @@ -620,6 +620,11 @@ struct mana_port_context { unsigned int rx_queue_size; unsigned int tx_queue_size; + /* MTU the RX queues were built for. Equal to ndev->mtu except during a + * swap, when the new set is built before ndev->mtu is updated. + */ + int configured_mtu; + mana_handle_t port_handle; mana_handle_t pf_filter_handle; @@ -710,6 +715,12 @@ struct mana_qset { unsigned int tx_queue_size; u32 priv_flags; + /* MTU the RX buffers of this set were sized for. It feeds + * mana_get_rxbuf_cfg(), so it is part of the queue-set + * configuration and must be swapped atomically with the queues. + */ + int mtu; + /* Per-queue-set debugfs root ("EQs"). Owned by the qset: it is * recreated by mana_create_eq() for each new set and torn down * with that set, so it must travel with the qset rather than @@ -735,7 +746,7 @@ struct mana_port_context *mana_qset_scratch_alloc(struct mana_port_context *apc) void mana_qset_scratch_free(struct mana_port_context *scratch); int mana_alloc_qset(struct mana_port_context *scratch, unsigned int num_queues, unsigned int rx_queue_size, unsigned int tx_queue_size, - u32 priv_flags, struct mana_qset *out); + u32 priv_flags, int mtu, struct mana_qset *out); int mana_publish_qset(struct mana_port_context *apc, struct mana_qset *newq, struct mana_qset *out_old); void mana_publish_close_if_needed(struct mana_port_context *apc); -- 2.43.0
