[PATCH net-next v7 07/13] net: mana: swap queue sets in mana_change_mtu
From: Wei Hu
Date: Fri Oct 16 2026 - 12:03:30 EST
From: Long Li <longli@xxxxxxxxxxxxx>
Carry the MTU in the queue set and size replacement RX buffers from it.
Publish ndev->mtu after RSS configuration succeeds; allocation failure
leaves the live queues and advertised MTU unchanged.
This full rebuild temporarily keeps both sets of SQ/RQ/CQ objects,
RX buffers and page pools live. The port-owned EQ pool is shared,
not doubled. Device resource limits may reject this temporary peak;
allocation failure preserves the live queues and configuration.
Reserve RAW-QP admission under vport_mutex for the entire live
replacement, including unpublished queues, fail-close and scratch
cleanup. Preserve validation, no-op and down-port behavior.
Signed-off-by: Long Li <longli@xxxxxxxxxxxxx>
Signed-off-by: Wei Hu <weh@xxxxxxxxxxxxx>
---
drivers/net/ethernet/microsoft/mana/mana_en.c | 66 ++++++++++++++-----
.../ethernet/microsoft/mana/mana_ethtool.c | 10 +--
include/net/mana/mana.h | 7 +-
3 files changed, 60 insertions(+), 23 deletions(-)
diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index c80a06ffbe50..c1ff4d9b8d45 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -956,32 +956,52 @@ int mana_pre_alloc_rxbufs(struct mana_port_context *mpc, int new_mtu, int num_qu
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;
+ 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;
+ /* Fail-close may release the Ethernet vport reference. */
+ mutex_lock(&mpc->vport_mutex);
+ if (mpc->channel_changing) {
+ mutex_unlock(&mpc->vport_mutex);
+ return -EBUSY;
+ }
+ mpc->channel_changing = true;
+ mutex_unlock(&mpc->vport_mutex);
+
+ scratch = mana_qset_scratch_alloc(mpc);
+ if (!scratch) {
+ err = -ENOMEM;
+ goto clear_flag;
}
- WRITE_ONCE(ndev->mtu, new_mtu);
+ err = mana_alloc_qset(mpc, scratch, mpc->num_queues,
+ mpc->rx_queue_size, mpc->tx_queue_size,
+ mpc->priv_flags, new_mtu, &newq);
+ if (err)
+ goto free_scratch;
- 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:
+ mana_publish_close_if_needed(mpc);
+ mana_qset_scratch_free(scratch);
+clear_flag:
+ mutex_lock(&mpc->vport_mutex);
+ mpc->channel_changing = false;
+ mutex_unlock(&mpc->vport_mutex);
return err;
}
@@ -3335,7 +3355,8 @@ 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);
@@ -4045,6 +4066,7 @@ 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;
}
/* Vport identity and port debugfs outlive queue sets. */
@@ -4061,6 +4083,7 @@ 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;
}
/* Scratch starts without SQs/RQs and borrows the port's EQ pool. Never call
@@ -4101,7 +4124,7 @@ void mana_qset_scratch_free(struct mana_port_context *scratch)
int mana_alloc_qset(struct mana_port_context *apc,
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;
@@ -4113,6 +4136,8 @@ int mana_alloc_qset(struct mana_port_context *apc,
scratch->tx_queue_size = tx_queue_size;
scratch->priv_flags = priv_flags;
+ scratch->configured_mtu = mtu;
+
err = mana_init_port_context(scratch);
if (err)
goto out_err;
@@ -4365,6 +4390,8 @@ int mana_publish_qset(struct mana_port_context *apc, struct mana_qset *newq,
if (err)
goto rollback;
+ WRITE_ONCE(ndev->mtu, apc->configured_mtu);
+
/* Publish fields before opening the gate; pair with TX/XDP read
* barriers. The post-gate full barrier cannot replace this.
*/
@@ -4420,6 +4447,8 @@ int mana_publish_qset(struct mana_port_context *apc, struct mana_qset *newq,
synchronize_net();
mana_fold_qset_rx_stats(apc, out_old);
+ WRITE_ONCE(ndev->mtu, apc->configured_mtu);
+
/* Publish restored fields before reopening the gate, as on success. */
smp_wmb();
@@ -4572,6 +4601,7 @@ 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 9c7c9879d0aa..43575aa3a168 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
@@ -738,7 +738,8 @@ static int mana_set_channels(struct net_device *ndev,
}
err = mana_alloc_qset(apc, 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;
@@ -827,7 +828,7 @@ static int mana_set_ringparam(struct net_device *ndev,
}
err = mana_alloc_qset(apc, 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);
@@ -916,8 +917,9 @@ static int mana_set_priv_flags(struct net_device *ndev, u32 priv_flags)
goto clear_flag;
}
- err = mana_alloc_qset(apc, scratch, apc->num_queues, apc->rx_queue_size,
- apc->tx_queue_size, priv_flags, &newq);
+ err = mana_alloc_qset(apc, scratch, apc->num_queues,
+ apc->rx_queue_size, apc->tx_queue_size,
+ priv_flags, apc->configured_mtu, &newq);
if (err)
goto free_scratch;
diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h
index 14025024acfa..60c7df78316c 100644
--- a/include/net/mana/mana.h
+++ b/include/net/mana/mana.h
@@ -637,6 +637,10 @@ struct mana_port_context {
unsigned int rx_queue_size;
unsigned int tx_queue_size;
+ /* MTU used to size RX buffers, independent of ndev->mtu during a swap.
+ */
+ int configured_mtu;
+
mana_handle_t port_handle;
mana_handle_t pf_filter_handle;
@@ -713,6 +717,7 @@ struct mana_qset {
unsigned int tx_queue_size;
u32 priv_flags;
+ int mtu;
};
netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev);
@@ -735,7 +740,7 @@ static inline struct mana_stats_rx *mana_rxq_stats(struct mana_rxq *rxq)
int mana_alloc_qset(struct mana_port_context *apc,
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