diff options
| -rw-r--r-- | sys/dev/em/if_em.c | 72 |
1 files changed, 60 insertions, 12 deletions
diff --git a/sys/dev/em/if_em.c b/sys/dev/em/if_em.c index d8bf16bb16738..192777db1737a 100644 --- a/sys/dev/em/if_em.c +++ b/sys/dev/em/if_em.c @@ -166,6 +166,9 @@ static void em_clean_transmit_interrupts(struct adapter *); static int em_allocate_receive_structures(struct adapter *); static int em_allocate_transmit_structures(struct adapter *); static void em_process_receive_interrupts(struct adapter *, int); +#ifndef __NO_STRICT_ALIGNMENT +static int em_fixup_rx(struct adapter *); +#endif static void em_receive_checksum(struct adapter *, struct em_rx_desc *, struct mbuf *); @@ -687,16 +690,6 @@ em_ioctl(struct ifnet *ifp, u_long command, caddr_t data) break; case SIOCSIFMTU: { -#ifndef __NO_STRICT_ALIGNMENT - if (ifr->ifr_mtu > ETHERMTU) - /* - * XXX - * Due to the limitation of DMA engine, it needs fix-up - * code for strict alignment architectures. Disable - * jumbo frame until we have better solutions. - */ - error = EINVAL; -#else int max_frame_size; IOCTL_DEBUGOUT("ioctl rcv'd: SIOCSIFMTU (Set Interface MTU)"); @@ -725,7 +718,6 @@ em_ioctl(struct ifnet *ifp, u_long command, caddr_t data) ifp->if_mtu + ETHER_HDR_LEN + ETHER_CRC_LEN; em_init_locked(adapter); EM_UNLOCK(adapter); -#endif break; } case SIOCSIFFLAGS: @@ -2969,12 +2961,20 @@ em_process_receive_interrupts(struct adapter * adapter, int count) ifp->if_ipackets++; em_receive_checksum(adapter, current_desc, adapter->fmp); +#ifndef __NO_STRICT_ALIGNMENT + if (ifp->if_mtu > ETHERMTU && + em_fixup_rx(adapter) != 0) + goto skip; + +#endif if (current_desc->status & E1000_RXD_STAT_VP) VLAN_INPUT_TAG(ifp, adapter->fmp, (le16toh(current_desc->special) & E1000_RXD_SPC_VLAN_MASK), adapter->fmp = NULL); - +#ifndef __NO_STRICT_ALIGNMENT +skip: +#endif m = adapter->fmp; adapter->fmp = NULL; adapter->lmp = NULL; @@ -3012,6 +3012,54 @@ em_process_receive_interrupts(struct adapter * adapter, int count) return; } +#ifndef __NO_STRICT_ALIGNMENT +/* + * When jumbo frames are enabled we should realign entire payload on + * architecures with strict alignment. This is serious design mistake of 8254x + * as it nullifies DMA operations. 8254x just allows RX buffer size to be + * 2048/4096/8192/16384. What we really want is 2048 - ETHER_ALIGN to align its + * payload. On architecures without strict alignment restrictions 8254x still + * performs unaligned memory access which would reduce the performance too. + * To avoid copying over an entire frame to align, we allocate a new mbuf and + * copy ethernet header to the new mbuf. The new mbuf is prepended into the + * existing mbuf chain. + * + * Be aware, best performance of the 8254x is achived only when jumbo frame is + * not used at all on architectures with strict alignment. + */ +static int +em_fixup_rx(struct adapter *adapter) +{ + struct mbuf *m, *n; + int error; + + error = 0; + m = adapter->fmp; + if (m->m_len <= (MCLBYTES - ETHER_HDR_LEN)) { + bcopy(m->m_data, m->m_data + ETHER_HDR_LEN, m->m_len); + m->m_data += ETHER_HDR_LEN; + } else { + MGETHDR(n, M_DONTWAIT, MT_DATA); + if (n != NULL) { + bcopy(m->m_data, n->m_data, ETHER_HDR_LEN); + m->m_data += ETHER_HDR_LEN; + m->m_len -= ETHER_HDR_LEN; + n->m_len = ETHER_HDR_LEN; + M_MOVE_PKTHDR(n, m); + n->m_next = m; + adapter->fmp = n; + } else { + adapter->dropped_pkts++; + m_freem(adapter->fmp); + adapter->fmp = NULL; + error = ENOMEM; + } + } + + return (error); +} +#endif + /********************************************************************* * * Verify that the hardware indicated that the checksum is valid. |