platform/mellanox: mlxbf-tmfifo: Drop jumbo frames

[ Upstream commit fc4c655821546239abb3cf4274d66b9747aa87dd ]

This commit drops over-sized network packets to avoid tmfifo
queue stuck.

Fixes: 1357dfd7261f ("platform/mellanox: Add TmFifo driver for Mellanox BlueField Soc")
Signed-off-by: Liming Sun <limings@nvidia.com>
Reviewed-by: Vadim Pasternak <vadimp@nvidia.com>
Reviewed-by: David Thompson <davthompson@nvidia.com>
Link: https://lore.kernel.org/r/9318936c2447f76db475c985ca6d91f057efcd41.1693322547.git.limings@nvidia.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c
index ee8648a..a04ff89 100644 (file)
--- a/drivers/platform/mellanox/mlxbf-tmfifo.c
+++ b/drivers/platform/mellanox/mlxbf-tmfifo.c
@@ -205,7 +205,7 @@ static u8 mlxbf_tmfifo_net_default_mac[ETH_ALEN] = {
 static efi_char16_t mlxbf_tmfifo_efi_name[] = L"RshimMacAddr";
 
 /* Maximum L2 header length. */
-#define MLXBF_TMFIFO_NET_L2_OVERHEAD   36
+#define MLXBF_TMFIFO_NET_L2_OVERHEAD   (ETH_HLEN + VLAN_HLEN)
 
 /* Supported virtio-net features. */
 #define MLXBF_TMFIFO_NET_FEATURES \
@@ -623,13 +623,14 @@ static void mlxbf_tmfifo_rxtx_word(struct mlxbf_tmfifo_vring *vring,
  * flag is set.
  */
 static void mlxbf_tmfifo_rxtx_header(struct mlxbf_tmfifo_vring *vring,
-                                    struct vring_desc *desc,
+                                    struct vring_desc **desc,
                                     bool is_rx, bool *vring_change)
 {
        struct mlxbf_tmfifo *fifo = vring->fifo;
        struct virtio_net_config *config;
        struct mlxbf_tmfifo_msg_hdr hdr;
        int vdev_id, hdr_len;
+       bool drop_rx = false;
 
        /* Read/Write packet header. */
        if (is_rx) {
@@ -649,8 +650,8 @@ static void mlxbf_tmfifo_rxtx_header(struct mlxbf_tmfifo_vring *vring,
                        if (ntohs(hdr.len) >
                            __virtio16_to_cpu(virtio_legacy_is_little_endian(),
                                              config->mtu) +
-                           MLXBF_TMFIFO_NET_L2_OVERHEAD)
-                               return;
+                                             MLXBF_TMFIFO_NET_L2_OVERHEAD)
+                               drop_rx = true;
                } else {
                        vdev_id = VIRTIO_ID_CONSOLE;
                        hdr_len = 0;
@@ -665,16 +666,25 @@ static void mlxbf_tmfifo_rxtx_header(struct mlxbf_tmfifo_vring *vring,
 
                        if (!tm_dev2)
                                return;
-                       vring->desc = desc;
+                       vring->desc = *desc;
                        vring = &tm_dev2->vrings[MLXBF_TMFIFO_VRING_RX];
                        *vring_change = true;
                }
+
+               if (drop_rx && !IS_VRING_DROP(vring)) {
+                       if (vring->desc_head)
+                               mlxbf_tmfifo_release_pkt(vring);
+                       *desc = &vring->drop_desc;
+                       vring->desc_head = *desc;
+                       vring->desc = *desc;
+               }
+
                vring->pkt_len = ntohs(hdr.len) + hdr_len;
        } else {
                /* Network virtio has an extra header. */
                hdr_len = (vring->vdev_id == VIRTIO_ID_NET) ?
                           sizeof(struct virtio_net_hdr) : 0;
-               vring->pkt_len = mlxbf_tmfifo_get_pkt_len(vring, desc);
+               vring->pkt_len = mlxbf_tmfifo_get_pkt_len(vring, *desc);
                hdr.type = (vring->vdev_id == VIRTIO_ID_NET) ?
                            VIRTIO_ID_NET : VIRTIO_ID_CONSOLE;
                hdr.len = htons(vring->pkt_len - hdr_len);
@@ -723,7 +733,7 @@ static bool mlxbf_tmfifo_rxtx_one_desc(struct mlxbf_tmfifo_vring *vring,
 
        /* Beginning of a packet. Start to Rx/Tx packet header. */
        if (vring->pkt_len == 0) {
-               mlxbf_tmfifo_rxtx_header(vring, desc, is_rx, &vring_change);
+               mlxbf_tmfifo_rxtx_header(vring, &desc, is_rx, &vring_change);
                (*avail)--;
 
                /* Return if new packet is for another ring. */