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Add jumbo frame support for architectures with strict alignment.

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Reviewed by:	glebius
This commit is contained in:
yongari 2005-12-16 08:29:43 +00:00
parent 7d30e8712e
commit c549c6b4f0
1 changed files with 60 additions and 12 deletions
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72
sys/dev/em/if_em.c
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@ -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.