[LU-5956] o2iblnd: incorrect uses of kib_tx_t::tx_nfrags

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.8.0
• Labels: lnet
• Severity: 3
• Assignee: Isaac Huang (Inactive)
• Reporter: Isaac Huang (Inactive)

Description

      665 kiblnd_map_tx(lnet_ni_t *ni, kib_tx_t *tx,
......
      677         tx->tx_nfrags = nfrags;
      678 
      679         rd->rd_nfrags =                                                                                                                                                                                                                              
      680                 kiblnd_dma_map_sg(hdev->ibh_ibdev,
      681                                   tx->tx_frags, tx->tx_nfrags, tx->tx_dmadir);

As dma_map_sg() can return fewer entries in the mapped SG list, it may happen that "rd->rd_nfrags < tx->tx_nfrags". But the code seemed to assume "rd->rd_nfrags == tx->tx_nfrags":

642 kiblnd_unmap_tx(lnet_ni_t *ni, kib_tx_t *tx)
658                 kiblnd_dma_unmap_sg(tx->tx_pool->tpo_hdev->ibh_ibdev,
659                                     tx->tx_frags, tx->tx_nfrags, tx->tx_dmadir);

1474 kiblnd_send (lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg)
1550                 nob = offsetof(kib_get_msg_t, ibgm_rd.rd_frags[tx->tx_nfrags]);

1707 kiblnd_recv (lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg, int delayed,
1788                 nob = offsetof(kib_putack_msg_t, ibpam_rd.rd_frags[tx->tx_nfrags]);

It seemed that the # original SG entries is not needed anywhere in the code, so it can be fixed by assigning the # mapped SG entries to kib_tx_t::tx_nfrags.