net: mana: Enforce TX SGE limit and fix error cleanup

PATCH Superseded Aditya Garg 2 participants 5 messages Nov 12, 2025 – Nov 14, 2025

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Networking Network drivers InfiniBand Hyper-V/Azure core and drivers +1 more subsystems

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Aditya Garg

author

2025-11-12 13:11 UTC #0 lore raw

v4 cover net: mana: Enforce TX SGE limit and fix error cleanup

Add pre-transmission checks to block SKBs that exceed the hardware's SGE limit. Force software segmentation for GSO traffic and linearize non-GSO packets as needed.

Update TX error handling to drop failed SKBs and unmap resources immediately.

---
Changes in v4:
* Fix warning during build reported by kernel test robot
---
Aditya Garg (2):
net: mana: Handle SKB if TX SGEs exceed hardware limit
net: mana: Drop TX skb on post_work_request failure and unmap
resources

 .../net/ethernet/microsoft/mana/gdma_main.c   |  6 +--
 drivers/net/ethernet/microsoft/mana/mana_en.c | 44 ++++++++++++++++---
 .../ethernet/microsoft/mana/mana_ethtool.c    |  2 +
 include/net/mana/gdma.h                       |  6 ++-
 include/net/mana/mana.h                       |  2 +
 5 files changed, 48 insertions(+), 12 deletions(-)

Signature · 1 line

2.43.0

Aditya Garg

author

2025-11-12 13:11 UTC #1 lore raw

PATCH v4 1/2 net: mana: Handle SKB if TX SGEs exceed hardware limit

The MANA hardware supports a maximum of 30 scatter-gather entries (SGEs) per TX WQE. Exceeding this limit can cause TX failures.
Add ndo_features_check() callback to validate SKB layout before transmission. For GSO SKBs that would exceed the hardware SGE limit, clear NETIF_F_GSO_MASK to enforce software segmentation in the stack. Add a fallback in mana_start_xmit() to linearize non-GSO SKBs that still exceed the SGE limit.

Also, Add ethtool counter for SKBs linearized

Co-developed-by Dipayaan Roy <[email protected]>

Signed-off-by Dipayaan Roy <[email protected]>

Signed-off-by Aditya Garg <[email protected]>

---
 drivers/net/ethernet/microsoft/mana/mana_en.c | 37 ++++++++++++++++++-
 .../ethernet/microsoft/mana/mana_ethtool.c    |  2 +
 include/net/mana/gdma.h                       |  6 ++-
 include/net/mana/mana.h                       |  1 +
 4 files changed, 43 insertions(+), 3 deletions(-)

drivers/net/ethernet/microsoft/mana/mana_en.c +35 -2

index cccd5b63cee6..67ae5421f9ee 100644
@@ -11,6 +11,7 @@
 #include <linux/mm.h>
 #include <linux/pci.h>
 #include <linux/export.h>
+#include <linux/skbuff.h>
 
 #include <net/checksum.h>
 #include <net/ip6_checksum.h>

@@ -329,6 +330,20 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	cq = &apc->tx_qp[txq_idx].tx_cq;
 	tx_stats = &txq->stats;
 
+	if (MAX_SKB_FRAGS + 2 > MAX_TX_WQE_SGL_ENTRIES &&
+	    skb_shinfo(skb)->nr_frags + 2 > MAX_TX_WQE_SGL_ENTRIES) {
+		/* GSO skb with Hardware SGE limit exceeded is not expected here
+		 * as they are handled in mana_features_check() callback
+		 */
+		if (skb_linearize(skb)) {
+			netdev_warn_once(ndev, "Failed to linearize skb with nr_frags=%d and is_gso=%d\n",
+					 skb_shinfo(skb)->nr_frags,
+					 skb_is_gso(skb));
+			goto tx_drop_count;
+		}
+		apc->eth_stats.linear_pkt_tx_cnt++;
+	}
+
 	pkg.tx_oob.s_oob.vcq_num = cq->gdma_id;
 	pkg.tx_oob.s_oob.vsq_frame = txq->vsq_frame;

@@ -442,8 +457,6 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 		}
 	}
 
-	WARN_ON_ONCE(pkg.wqe_req.num_sge > MAX_TX_WQE_SGL_ENTRIES);
-
 	if (pkg.wqe_req.num_sge <= ARRAY_SIZE(pkg.sgl_array)) {
 		pkg.wqe_req.sgl = pkg.sgl_array;
 	} else {

@@ -518,6 +531,25 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	return NETDEV_TX_OK;
 }
 
+static netdev_features_t mana_features_check(struct sk_buff *skb,
+					     struct net_device *ndev,
+					     netdev_features_t features)
+{
+	if (MAX_SKB_FRAGS + 2 > MAX_TX_WQE_SGL_ENTRIES &&
+	    skb_shinfo(skb)->nr_frags + 2 > MAX_TX_WQE_SGL_ENTRIES) {
+		/* Exceeds HW SGE limit.
+		 * GSO case:
+		 *   Disable GSO so the stack will software-segment the skb
+		 *   into smaller skbs that fit the SGE budget.
+		 * Non-GSO case:
+		 *   The xmit path will attempt skb_linearize() as a fallback.
+		 */
+		if (skb_is_gso(skb))
+			features &= ~NETIF_F_GSO_MASK;
+	}
+	return features;
+}
+
 static void mana_get_stats64(struct net_device *ndev,
 			     struct rtnl_link_stats64 *st)
 {

@@ -878,6 +910,7 @@ static const struct net_device_ops mana_devops = {
 	.ndo_open		= mana_open,
 	.ndo_stop		= mana_close,
 	.ndo_select_queue	= mana_select_queue,
+	.ndo_features_check	= mana_features_check,
 	.ndo_start_xmit		= mana_start_xmit,
 	.ndo_validate_addr	= eth_validate_addr,
 	.ndo_get_stats64	= mana_get_stats64,

drivers/net/ethernet/microsoft/mana/mana_ethtool.c +2 -0

index a1afa75a9463..fa5e1a2f06a9 100644
@@ -71,6 +71,8 @@ static const struct mana_stats_desc mana_eth_stats[] = {
 	{"tx_cq_err", offsetof(struct mana_ethtool_stats, tx_cqe_err)},
 	{"tx_cqe_unknown_type", offsetof(struct mana_ethtool_stats,
 					tx_cqe_unknown_type)},
+	{"linear_pkt_tx_cnt", offsetof(struct mana_ethtool_stats,
+					linear_pkt_tx_cnt)},
 	{"rx_coalesced_err", offsetof(struct mana_ethtool_stats,
 					rx_coalesced_err)},
 	{"rx_cqe_unknown_type", offsetof(struct mana_ethtool_stats,

include/net/mana/gdma.h +5 -1

index 637f42485dba..84614ebe0f4c 100644
@@ -592,6 +592,9 @@ enum {
 #define GDMA_DRV_CAP_FLAG_1_HANDLE_RECONFIG_EQE BIT(17)
 #define GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE BIT(6)
 
+/* Driver supports linearizing the skb when num_sge exceeds hardware limit */
+#define GDMA_DRV_CAP_FLAG_1_SKB_LINEARIZE BIT(20)
+
 #define GDMA_DRV_CAP_FLAGS1 \
 	(GDMA_DRV_CAP_FLAG_1_EQ_SHARING_MULTI_VPORT | \
 	 GDMA_DRV_CAP_FLAG_1_NAPI_WKDONE_FIX | \

@@ -601,7 +604,8 @@ enum {
 	 GDMA_DRV_CAP_FLAG_1_DYNAMIC_IRQ_ALLOC_SUPPORT | \
 	 GDMA_DRV_CAP_FLAG_1_SELF_RESET_ON_EQE | \
 	 GDMA_DRV_CAP_FLAG_1_HANDLE_RECONFIG_EQE | \
-	 GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE)
+	 GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE | \
+	 GDMA_DRV_CAP_FLAG_1_SKB_LINEARIZE)
 
 #define GDMA_DRV_CAP_FLAGS2 0

include/net/mana/mana.h +1 -0

index 8906901535f5..50a532fb30d6 100644
@@ -404,6 +404,7 @@ struct mana_ethtool_stats {
 	u64 hc_tx_err_gdma;
 	u64 tx_cqe_err;
 	u64 tx_cqe_unknown_type;
+	u64 linear_pkt_tx_cnt;
 	u64 rx_coalesced_err;
 	u64 rx_cqe_unknown_type;
 };

Signature · 1 line

2.43.0

Eric Dumazet

2025-11-12 13:55 UTC #2 lore raw

Re: [PATCH net-next v4 1/2] net: mana: Handle SKB if TX SGEs exceed hardware limit

Quoted 64 lines · Aditya Garg

Also, Add ethtool counter for SKBs linearized

Co-developed-by Dipayaan Roy <[email protected]>

Signed-off-by Dipayaan Roy <[email protected]>

Signed-off-by Aditya Garg <[email protected]>

---
 drivers/net/ethernet/microsoft/mana/mana_en.c | 37 ++++++++++++++++++-
 .../ethernet/microsoft/mana/mana_ethtool.c    |  2 +
 include/net/mana/gdma.h                       |  6 ++-
 include/net/mana/mana.h                       |  1 +
 4 files changed, 43 insertions(+), 3 deletions(-)

drivers/net/ethernet/microsoft/mana/mana_en.c +15 -2

index cccd5b63cee6..67ae5421f9ee 100644
@@ -11,6 +11,7 @@
 #include <linux/mm.h>
 #include <linux/pci.h>
 #include <linux/export.h>
+#include <linux/skbuff.h>
 
 #include <net/checksum.h>
 #include <net/ip6_checksum.h>

@@ -329,6 +330,20 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev)
        cq = &apc->tx_qp[txq_idx].tx_cq;
        tx_stats = &txq->stats;
 
+       if (MAX_SKB_FRAGS + 2 > MAX_TX_WQE_SGL_ENTRIES &&
+           skb_shinfo(skb)->nr_frags + 2 > MAX_TX_WQE_SGL_ENTRIES) {
+               /* GSO skb with Hardware SGE limit exceeded is not expected here
+                * as they are handled in mana_features_check() callback
+                */
+               if (skb_linearize(skb)) {
+                       netdev_warn_once(ndev, "Failed to linearize skb with nr_frags=%d and is_gso=%d\n",
+                                        skb_shinfo(skb)->nr_frags,
+                                        skb_is_gso(skb));
+                       goto tx_drop_count;
+               }
+               apc->eth_stats.linear_pkt_tx_cnt++;
+       }
+
        pkg.tx_oob.s_oob.vcq_num = cq->gdma_id;
        pkg.tx_oob.s_oob.vsq_frame = txq->vsq_frame;

@@ -442,8 +457,6 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev)
                }
        }
 
-       WARN_ON_ONCE(pkg.wqe_req.num_sge > MAX_TX_WQE_SGL_ENTRIES);
-
        if (pkg.wqe_req.num_sge <= ARRAY_SIZE(pkg.sgl_array)) {
                pkg.wqe_req.sgl = pkg.sgl_array;
        } else {

drivers/net/ethernet/microsoft/mana/mana_en.c netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev) · line 533

Quoted 3 lines

drivers/net/ethernet/microsoft/mana/mana_en.c +0 -0

@@ -518,6 +531,25 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev)
        return NETDEV_TX_OK;
 }

#if MAX_SKB_FRAGS + 2 > MAX_TX_WQE_SGL_ENTRIES

Quoted 4 lines

drivers/net/ethernet/microsoft/mana/mana_en.c +4 -0

+static netdev_features_t mana_features_check(struct sk_buff *skb,
+                                            struct net_device *ndev,
+                                            netdev_features_t features)
+{

drivers/net/ethernet/microsoft/mana/mana_en.c netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev) · line 547

Quoted 10 lines

drivers/net/ethernet/microsoft/mana/mana_en.c +10 -0

+       if (MAX_SKB_FRAGS + 2 > MAX_TX_WQE_SGL_ENTRIES &&
+           skb_shinfo(skb)->nr_frags + 2 > MAX_TX_WQE_SGL_ENTRIES) {
+               /* Exceeds HW SGE limit.
+                * GSO case:
+                *   Disable GSO so the stack will software-segment the skb
+                *   into smaller skbs that fit the SGE budget.
+                * Non-GSO case:
+                *   The xmit path will attempt skb_linearize() as a fallback.
+                */
+               if (skb_is_gso(skb))

No need to test skb_is_gso(skb), you can clear bits, this will be a NOP if the packet is non GSO anyway.

drivers/net/ethernet/microsoft/mana/mana_en.c netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev) · line 551

Quoted 4 lines

drivers/net/ethernet/microsoft/mana/mana_en.c +4 -0

+                       features &= ~NETIF_F_GSO_MASK;
+       }
+       return features;
+}

#endif

drivers/net/ethernet/microsoft/mana/mana_en.c static const struct net_device_ops mana_devops = { · line 913

Quoted 9 lines

drivers/net/ethernet/microsoft/mana/mana_en.c +2 -0

+
 static void mana_get_stats64(struct net_device *ndev,
                             struct rtnl_link_stats64 *st)
 {

@@ -878,6 +910,7 @@ static const struct net_device_ops mana_devops = {
        .ndo_open               = mana_open,
        .ndo_stop               = mana_close,
        .ndo_select_queue       = mana_select_queue,
+       .ndo_features_check     = mana_features_check,

Note that if your mana_features_check() is a nop if MAX_SKB_FRAGS is small enough,
you could set a non NULL .ndo_features_check based on a preprocessor condition

#if MAX_SKB_FRAGS + 2 > MAX_TX_WQE_SGL_ENTRIES
    .ndo_features_check = ....

#endif

This would avoid an expensive indirect call when possible.

Quoted 55 lines

drivers/net/ethernet/microsoft/mana/mana_en.c +0 -0

        .ndo_start_xmit         = mana_start_xmit,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_get_stats64        = mana_get_stats64,

drivers/net/ethernet/microsoft/mana/mana_ethtool.c +2 -0

index a1afa75a9463..fa5e1a2f06a9 100644
@@ -71,6 +71,8 @@ static const struct mana_stats_desc mana_eth_stats[] = {
        {"tx_cq_err", offsetof(struct mana_ethtool_stats, tx_cqe_err)},
        {"tx_cqe_unknown_type", offsetof(struct mana_ethtool_stats,
                                        tx_cqe_unknown_type)},
+       {"linear_pkt_tx_cnt", offsetof(struct mana_ethtool_stats,
+                                       linear_pkt_tx_cnt)},
        {"rx_coalesced_err", offsetof(struct mana_ethtool_stats,
                                        rx_coalesced_err)},
        {"rx_cqe_unknown_type", offsetof(struct mana_ethtool_stats,

include/net/mana/gdma.h +5 -1

index 637f42485dba..84614ebe0f4c 100644
@@ -592,6 +592,9 @@ enum {
 #define GDMA_DRV_CAP_FLAG_1_HANDLE_RECONFIG_EQE BIT(17)
 #define GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE BIT(6)
 
+/* Driver supports linearizing the skb when num_sge exceeds hardware limit */
+#define GDMA_DRV_CAP_FLAG_1_SKB_LINEARIZE BIT(20)
+
 #define GDMA_DRV_CAP_FLAGS1 \
        (GDMA_DRV_CAP_FLAG_1_EQ_SHARING_MULTI_VPORT | \
         GDMA_DRV_CAP_FLAG_1_NAPI_WKDONE_FIX | \

@@ -601,7 +604,8 @@ enum {
         GDMA_DRV_CAP_FLAG_1_DYNAMIC_IRQ_ALLOC_SUPPORT | \
         GDMA_DRV_CAP_FLAG_1_SELF_RESET_ON_EQE | \
         GDMA_DRV_CAP_FLAG_1_HANDLE_RECONFIG_EQE | \
-        GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE)
+        GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE | \
+        GDMA_DRV_CAP_FLAG_1_SKB_LINEARIZE)
 
 #define GDMA_DRV_CAP_FLAGS2 0

include/net/mana/mana.h +1 -1

index 8906901535f5..50a532fb30d6 100644
@@ -404,6 +404,7 @@ struct mana_ethtool_stats {
        u64 hc_tx_err_gdma;
        u64 tx_cqe_err;
        u64 tx_cqe_unknown_type;
+       u64 linear_pkt_tx_cnt;
        u64 rx_coalesced_err;
        u64 rx_cqe_unknown_type;
 };
--

2.43.0

Aditya Garg

author

2025-11-14 20:58 UTC #3 lore raw

Re: [PATCH net-next v4 1/2] net: mana: Handle SKB if TX SGEs exceed hardware limit

Quoted 159 lines · Eric Dumazet

Quoted 64 lines · Aditya Garg

Also, Add ethtool counter for SKBs linearized

Co-developed-by Dipayaan Roy <[email protected]>

Signed-off-by Dipayaan Roy <[email protected]>

Signed-off-by Aditya Garg <[email protected]>

---
  drivers/net/ethernet/microsoft/mana/mana_en.c | 37 ++++++++++++++++++-
  .../ethernet/microsoft/mana/mana_ethtool.c    |  2 +
  include/net/mana/gdma.h                       |  6 ++-
  include/net/mana/mana.h                       |  1 +
  4 files changed, 43 insertions(+), 3 deletions(-)

drivers/net/ethernet/microsoft/mana/mana_en.c +15 -2

index cccd5b63cee6..67ae5421f9ee 100644
@@ -11,6 +11,7 @@
  #include <linux/mm.h>
  #include <linux/pci.h>
  #include <linux/export.h>
+#include <linux/skbuff.h>
 
  #include <net/checksum.h>
  #include <net/ip6_checksum.h>

@@ -329,6 +330,20 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev)
         cq = &apc->tx_qp[txq_idx].tx_cq;
         tx_stats = &txq->stats;
 
+       if (MAX_SKB_FRAGS + 2 > MAX_TX_WQE_SGL_ENTRIES &&
+           skb_shinfo(skb)->nr_frags + 2 > MAX_TX_WQE_SGL_ENTRIES) {
+               /* GSO skb with Hardware SGE limit exceeded is not expected here
+                * as they are handled in mana_features_check() callback
+                */
+               if (skb_linearize(skb)) {
+                       netdev_warn_once(ndev, "Failed to linearize skb with nr_frags=%d and is_gso=%d\n",
+                                        skb_shinfo(skb)->nr_frags,
+                                        skb_is_gso(skb));
+                       goto tx_drop_count;
+               }
+               apc->eth_stats.linear_pkt_tx_cnt++;
+       }
+
         pkg.tx_oob.s_oob.vcq_num = cq->gdma_id;
         pkg.tx_oob.s_oob.vsq_frame = txq->vsq_frame;

@@ -442,8 +457,6 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev)
                 }
         }
 
-       WARN_ON_ONCE(pkg.wqe_req.num_sge > MAX_TX_WQE_SGL_ENTRIES);
-
         if (pkg.wqe_req.num_sge <= ARRAY_SIZE(pkg.sgl_array)) {
                 pkg.wqe_req.sgl = pkg.sgl_array;
         } else {

drivers/net/ethernet/microsoft/mana/mana_en.c netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev) · line 533

Quoted 3 lines

drivers/net/ethernet/microsoft/mana/mana_en.c +0 -0

@@ -518,6 +531,25 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev)
         return NETDEV_TX_OK;
  }

#if MAX_SKB_FRAGS + 2 > MAX_TX_WQE_SGL_ENTRIES

Quoted 4 lines

drivers/net/ethernet/microsoft/mana/mana_en.c +4 -0

+static netdev_features_t mana_features_check(struct sk_buff *skb,
+                                            struct net_device *ndev,
+                                            netdev_features_t features)
+{

drivers/net/ethernet/microsoft/mana/mana_en.c netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev) · line 547

Quoted 10 lines

drivers/net/ethernet/microsoft/mana/mana_en.c +10 -0

+       if (MAX_SKB_FRAGS + 2 > MAX_TX_WQE_SGL_ENTRIES &&
+           skb_shinfo(skb)->nr_frags + 2 > MAX_TX_WQE_SGL_ENTRIES) {
+               /* Exceeds HW SGE limit.
+                * GSO case:
+                *   Disable GSO so the stack will software-segment the skb
+                *   into smaller skbs that fit the SGE budget.
+                * Non-GSO case:
+                *   The xmit path will attempt skb_linearize() as a fallback.
+                */
+               if (skb_is_gso(skb))

No need to test skb_is_gso(skb), you can clear bits, this will be a NOP if the packet is non GSO anyway.

drivers/net/ethernet/microsoft/mana/mana_en.c netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev) · line 551

Quoted 4 lines

drivers/net/ethernet/microsoft/mana/mana_en.c +4 -0

+                       features &= ~NETIF_F_GSO_MASK;
+       }
+       return features;
+}

#endif

drivers/net/ethernet/microsoft/mana/mana_en.c static const struct net_device_ops mana_devops = { · line 913

Quoted 9 lines

drivers/net/ethernet/microsoft/mana/mana_en.c +2 -0

+
  static void mana_get_stats64(struct net_device *ndev,
                              struct rtnl_link_stats64 *st)
  {

@@ -878,6 +910,7 @@ static const struct net_device_ops mana_devops = {
         .ndo_open               = mana_open,
         .ndo_stop               = mana_close,
         .ndo_select_queue       = mana_select_queue,
+       .ndo_features_check     = mana_features_check,

Note that if your mana_features_check() is a nop if MAX_SKB_FRAGS is small enough,
you could set a non NULL .ndo_features_check based on a preprocessor condition

#if MAX_SKB_FRAGS + 2 > MAX_TX_WQE_SGL_ENTRIES
     .ndo_features_check = ....

#endif

This would avoid an expensive indirect call when possible.

Quoted 40 lines

drivers/net/ethernet/microsoft/mana/mana_en.c +0 -0

         .ndo_start_xmit         = mana_start_xmit,
         .ndo_validate_addr      = eth_validate_addr,
         .ndo_get_stats64        = mana_get_stats64,

drivers/net/ethernet/microsoft/mana/mana_ethtool.c +2 -0

index a1afa75a9463..fa5e1a2f06a9 100644
@@ -71,6 +71,8 @@ static const struct mana_stats_desc mana_eth_stats[] = {
         {"tx_cq_err", offsetof(struct mana_ethtool_stats, tx_cqe_err)},
         {"tx_cqe_unknown_type", offsetof(struct mana_ethtool_stats,
                                         tx_cqe_unknown_type)},
+       {"linear_pkt_tx_cnt", offsetof(struct mana_ethtool_stats,
+                                       linear_pkt_tx_cnt)},
         {"rx_coalesced_err", offsetof(struct mana_ethtool_stats,
                                         rx_coalesced_err)},
         {"rx_cqe_unknown_type", offsetof(struct mana_ethtool_stats,

include/net/mana/gdma.h +5 -1

index 637f42485dba..84614ebe0f4c 100644
@@ -592,6 +592,9 @@ enum {
  #define GDMA_DRV_CAP_FLAG_1_HANDLE_RECONFIG_EQE BIT(17)
  #define GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE BIT(6)
 
+/* Driver supports linearizing the skb when num_sge exceeds hardware limit */
+#define GDMA_DRV_CAP_FLAG_1_SKB_LINEARIZE BIT(20)
+
  #define GDMA_DRV_CAP_FLAGS1 \
         (GDMA_DRV_CAP_FLAG_1_EQ_SHARING_MULTI_VPORT | \
          GDMA_DRV_CAP_FLAG_1_NAPI_WKDONE_FIX | \

@@ -601,7 +604,8 @@ enum {
          GDMA_DRV_CAP_FLAG_1_DYNAMIC_IRQ_ALLOC_SUPPORT | \
          GDMA_DRV_CAP_FLAG_1_SELF_RESET_ON_EQE | \
          GDMA_DRV_CAP_FLAG_1_HANDLE_RECONFIG_EQE | \
-        GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE)
+        GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE | \
+        GDMA_DRV_CAP_FLAG_1_SKB_LINEARIZE)
 
  #define GDMA_DRV_CAP_FLAGS2 0

Quoted 15 lines

Quoted 13 lines

include/net/mana/mana.h +1 -1

index 8906901535f5..50a532fb30d6 100644
@@ -404,6 +404,7 @@ struct mana_ethtool_stats {
         u64 hc_tx_err_gdma;
         u64 tx_cqe_err;
         u64 tx_cqe_unknown_type;
+       u64 linear_pkt_tx_cnt;
         u64 rx_coalesced_err;
         u64 rx_cqe_unknown_type;
  };
--

Quoted 2 lines

2.43.0

Thanks for the review Eric. I will incorporate these changes in next revision.

Regards,
Aditya

Aditya Garg

author

2025-11-12 13:11 UTC #4 lore raw

PATCH v4 2/2 net: mana: Drop TX skb on post_work_request failure and unmap resources

In reply to Aditya Garg

Drop TX packets when posting the work request fails and ensure DMA mappings are always cleaned up.

Signed-off-by Aditya Garg <[email protected]>

---
Changes in v4:
* Fix warning during build reported by kernel test robot

---
 drivers/net/ethernet/microsoft/mana/gdma_main.c | 6 +-----
 drivers/net/ethernet/microsoft/mana/mana_en.c   | 7 +++----
 include/net/mana/mana.h                         | 1 +
 3 files changed, 5 insertions(+), 9 deletions(-)

drivers/net/ethernet/microsoft/mana/gdma_main.c +1 -5

index effe0a2f207a..8fd70b34807a 100644
@@ -1300,7 +1300,6 @@ int mana_gd_post_work_request(struct gdma_queue *wq,
 			      struct gdma_posted_wqe_info *wqe_info)
 {
 	u32 client_oob_size = wqe_req->inline_oob_size;
-	struct gdma_context *gc;
 	u32 sgl_data_size;
 	u32 max_wqe_size;
 	u32 wqe_size;

@@ -1330,11 +1329,8 @@ int mana_gd_post_work_request(struct gdma_queue *wq,
 	if (wqe_size > max_wqe_size)
 		return -EINVAL;
 
-	if (wq->monitor_avl_buf && wqe_size > mana_gd_wq_avail_space(wq)) {
-		gc = wq->gdma_dev->gdma_context;
-		dev_err(gc->dev, "unsuccessful flow control!\n");
+	if (wq->monitor_avl_buf && wqe_size > mana_gd_wq_avail_space(wq))
 		return -ENOSPC;
-	}
 
 	if (wqe_info)
 		wqe_info->wqe_size_in_bu = wqe_size / GDMA_WQE_BU_SIZE;

drivers/net/ethernet/microsoft/mana/mana_en.c +3 -4

index 67ae5421f9ee..066d822f68f0 100644
@@ -491,9 +491,9 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 
 	if (err) {
 		(void)skb_dequeue_tail(&txq->pending_skbs);
+		mana_unmap_skb(skb, apc);
 		netdev_warn(ndev, "Failed to post TX OOB: %d\n", err);
-		err = NETDEV_TX_BUSY;
-		goto tx_busy;
+		goto free_sgl_ptr;
 	}
 
 	err = NETDEV_TX_OK;

@@ -513,7 +513,6 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	tx_stats->bytes += len + ((num_gso_seg - 1) * gso_hs);
 	u64_stats_update_end(&tx_stats->syncp);
 
-tx_busy:
 	if (netif_tx_queue_stopped(net_txq) && mana_can_tx(gdma_sq)) {
 		netif_tx_wake_queue(net_txq);
 		apc->eth_stats.wake_queue++;

@@ -1679,7 +1678,7 @@ static int mana_move_wq_tail(struct gdma_queue *wq, u32 num_units)
 	return 0;
 }
 
-static void mana_unmap_skb(struct sk_buff *skb, struct mana_port_context *apc)
+void mana_unmap_skb(struct sk_buff *skb, struct mana_port_context *apc)
 {
 	struct mana_skb_head *ash = (struct mana_skb_head *)skb->head;
 	struct gdma_context *gc = apc->ac->gdma_dev->gdma_context;

include/net/mana/mana.h +1 -0

index 50a532fb30d6..d05457d3e1ab 100644
@@ -585,6 +585,7 @@ int mana_set_bw_clamp(struct mana_port_context *apc, u32 speed,
 void mana_query_phy_stats(struct mana_port_context *apc);
 int mana_pre_alloc_rxbufs(struct mana_port_context *apc, int mtu, int num_queues);
 void mana_pre_dealloc_rxbufs(struct mana_port_context *apc);
+void mana_unmap_skb(struct sk_buff *skb, struct mana_port_context *apc);
 
 extern const struct ethtool_ops mana_ethtool_ops;
 extern struct dentry *mana_debugfs_root;

Signature · 1 line

2.43.0