hinic3: Fix skb linearization mismatch and drop skb when skb_checksum_help() failed

Previously, hinic3_send_one_skb() cached the skb fragment count before
calling hinic3_tx_offload(). If hinic3_tx_csum() falls back to
skb_checksum_help() for unsupported tunnel packets, the skb may be
linearized. Continuing to build the TX descriptor with the stale
fragment count leads to a descriptor mismatch, which can trigger
out-of-bounds DMA reads or IOMMU faults.

Furthermore, the old code ignored the return value of skb_checksum_help(),
transmitting corrupted packets with incomplete checksums upon failure.

Fix this by:
1. Moving the hinic3_tx_offload() call before calculating 'num_sge' to
   ensure the correct fragment count is used if the SKB is linearized.
2. Propagating skb_checksum_help() errors and returning
   HINIC3_TX_OFFLOAD_INVALID to properly drop the skb.

Fixes: 17fcb3dc12bb ("hinic3: module initialization and tx/rx logic")
Co-developed-by: Teng Peisen <tengpeisen@huawei.com>
Signed-off-by: Teng Peisen <tengpeisen@huawei.com>
Co-developed-by: Wu Di <wudi234@huawei.com>
Signed-off-by: Wu Di <wudi234@huawei.com>
Signed-off-by: Fan Gong <gongfan1@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/78d8c61cab588240948eaddcb437d59add9f77ae.1786448013.git.tengpeisen@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions