lkml.org 
[lkml]   [2006]   [Mar]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Subject[PATCH 3 of 20] ipath - copy and send routines for sending an skb
    Date
    From
    Signed-off-by: Bryan O'Sullivan <bos@pathscale.com>

    diff -r 19bdf20bc544 -r 227b3e7c27ce drivers/infiniband/hw/ipath/ipath_copy.c
    --- /dev/null Thu Jan 1 00:00:00 1970 +0000
    +++ b/drivers/infiniband/hw/ipath/ipath_copy.c Thu Mar 9 16:15:23 2006 -0800
    @@ -0,0 +1,504 @@
    +/*
    + * Copyright (c) 2003, 2004, 2005, 2006 PathScale, Inc. All rights reserved.
    + *
    + * This software is available to you under a choice of one of two
    + * licenses. You may choose to be licensed under the terms of the GNU
    + * General Public License (GPL) Version 2, available from the file
    + * COPYING in the main directory of this source tree, or the
    + * OpenIB.org BSD license below:
    + *
    + * Redistribution and use in source and binary forms, with or
    + * without modification, are permitted provided that the following
    + * conditions are met:
    + *
    + * - Redistributions of source code must retain the above
    + * copyright notice, this list of conditions and the following
    + * disclaimer.
    + *
    + * - Redistributions in binary form must reproduce the above
    + * copyright notice, this list of conditions and the following
    + * disclaimer in the documentation and/or other materials
    + * provided with the distribution.
    + *
    + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
    + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
    + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
    + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    + * SOFTWARE.
    + */
    +
    +/*
    + * This file provides support for doing sk_buff buffer swapping between
    + * the low level driver eager buffers, and the network layer. It's part
    + * of the core driver, rather than the ether driver, because it relies
    + * on variables and functions in the core driver. It exports a single
    + * entry point for use in the ipath_ether module.
    + */
    +
    +#include <linux/io.h>
    +#include <linux/pci.h>
    +#include <linux/netdevice.h>
    +
    +#include "ipath_kernel.h"
    +#include "ips_common.h"
    +
    +/**
    + * layer_send_getpiobuf - allocate, setup and copy out a PIO send buffer
    + * @dd: the infinipath device
    + * @cdp: the data to copy
    + *
    + * Allocate a PIO send buffer, initialize the header and copy it out.
    + */
    +static int layer_send_getpiobuf(struct ipath_devdata *dd,
    + struct copy_data_s *cdp)
    +{
    + u32 extra_bytes;
    + u32 len, nwords, hdrwords;
    + u32 __iomem *piobuf;
    +
    + piobuf = ipath_getpiobuf(dd, NULL);
    + if (!piobuf) {
    + cdp->error = -EBUSY;
    + return cdp->error;
    + }
    +
    + /*
    + * Compute the max amount of data that can fit into a PIO buffer.
    + * buffer size - header size - trigger qword length & flags - CRC
    + */
    + len = dd->ipath_ibmaxlen -
    + sizeof(struct ether_header) - 8 - (SIZE_OF_CRC << 2);
    + if (len > dd->ipath_rcvegrbufsize)
    + len = dd->ipath_rcvegrbufsize;
    + if (len > (cdp->len + cdp->extra))
    + len = (cdp->len + cdp->extra);
    + /* Compute word aligment (i.e., (len & 3) ? 4 - (len & 3) : 0) */
    + extra_bytes = (4 - len) & 3;
    + nwords = (sizeof(struct ether_header) + len + extra_bytes) >> 2;
    + cdp->hdr->lrh[2] = htons(nwords + SIZE_OF_CRC);
    + cdp->hdr->bth[0] = htonl((OPCODE_ITH4X << 24) +
    + (extra_bytes << 20) +
    + IPS_DEFAULT_P_KEY);
    + cdp->hdr->sub_opcode = OPCODE_ENCAP;
    +
    + cdp->hdr->bth[2] = 0;
    + /*
    + * Generate an interrupt on the receive side for the last
    + * fragment.
    + */
    + cdp->hdr->iph.pkt_flags = ((cdp->len + cdp->extra) == len)
    + ? INFINIPATH_KPF_INTR : 0;
    + cdp->hdr->iph.chksum =
    + (u16) IPS_LRH_BTH + (u16) (nwords + SIZE_OF_CRC) -
    + (u16) ((cdp->hdr->iph.ver_port_tid_offset >> 16) & 0xFFFF) -
    + (u16) (cdp->hdr->iph.ver_port_tid_offset & 0xFFFF) -
    + (u16) cdp->hdr->iph.pkt_flags;
    +
    + ipath_cdbg(VERBOSE, "send %d (%x %x %x %x %x %x %x)\n", nwords,
    + cdp->hdr->lrh[0], cdp->hdr->lrh[1],
    + cdp->hdr->lrh[2], cdp->hdr->lrh[3],
    + cdp->hdr->bth[0], cdp->hdr->bth[1], cdp->hdr->bth[2]);
    + /*
    + * Write len to control qword, no flags.
    + * +1 is for the qword padding of pbc.
    + */
    + writeq(nwords + 1ULL, (u64 __iomem *) piobuf);
    + /* we have to flush after the PBC for correctness on some cpus
    + * or WC buffer can be written out of order */
    + ipath_flush_wc();
    + piobuf += 2;
    + hdrwords = sizeof(struct ether_header) >> 2;
    + __iowrite32_copy(piobuf, cdp->hdr, hdrwords);
    + cdp->csum_pio = &((struct ether_header __iomem *)piobuf)->csum;
    + cdp->to = piobuf + hdrwords;
    + cdp->flen = nwords - hdrwords;
    + cdp->hdr->frag_num++;
    + return 0;
    +}
    +
    +/**
    + * copy_extra_dword - copy the last full dword
    + * @dd: the infinipath device
    + * @cdp: the data to copy
    + * @dosum: write a checksum if true
    + *
    + * copy the last full dword when that's the "extra" word, preceding it
    + * with a memory fence, so that all prior data is written to the PIO
    + * buffer before the trigger word, to enforce the correct bus ordering
    + * of the WC buffer contents on the bus.
    + */
    +static inline unsigned copy_extra_dword(struct ipath_devdata *dd,
    + struct copy_data_s *cdp,
    + unsigned dosum)
    +{
    + if (!cdp->flen && layer_send_getpiobuf(dd, cdp) < 0)
    + return 1;
    + /* write the checksum before the last PIO write, if requested. */
    + if (dosum && cdp->flen == 1)
    + __raw_writel(csum_fold(cdp->csum), cdp->csum_pio);
    + cdp->extra = 0;
    + cdp->flen -= 1;
    + if (!cdp->flen) { /* trigger word being written */
    + ipath_flush_wc();
    + __raw_writel(cdp->u.w, cdp->to++);
    + ipath_flush_wc();
    + } else /* still more to copy to pio buf */
    + __raw_writel(cdp->u.w, cdp->to++);
    + return 0;
    +}
    +
    +/**
    + * copy_a_buffer - copy a PIO buffer's worth to the PIO buffer
    + * @dd: the infinipath device
    + * @cdp: the destination
    + * @p: the data to copy
    + * @n: the amount to copy
    + * @dosum: write a checksum if true
    + *
    + * copy a PIO buffer's worth (or the skb fragment, at least) to the PIO
    + * buffer, adding a memory fence before the last word. We need the fence
    + * as part of forcing the WC ordering on some cpus, for the cases where
    + * it will be the trigger word. The final fence after the trigger word
    + * will be done either at the next chunk, or on final return from the caller
    + * Takes max byte count, returns byte count actually done (always rounded
    + * to dword multiple).
    + */
    +static u32 copy_a_buffer(struct ipath_devdata *dd, struct copy_data_s *cdp,
    + void *p, u32 n, unsigned dosum)
    +{
    + u32 *p32;
    +
    + if (!cdp->flen && layer_send_getpiobuf(dd, cdp) < 0)
    + return -1;
    + if (n > cdp->flen)
    + n = cdp->flen;
    + if (dosum && cdp->flen == n)
    + __raw_writel(csum_fold(cdp->csum), cdp->csum_pio);
    + p32 = p;
    + cdp->flen -= n;
    + if (!cdp->flen) { /* trigger word being written */
    + __iowrite32_copy(cdp->to, p32, n - 1);
    + cdp->to += n - 1;
    + ipath_flush_wc();
    + __raw_writel(p32[n - 1], cdp->to++);
    + ipath_flush_wc();
    + } else { /* still more to copy to pio buf */
    + __iowrite32_copy(cdp->to, p32, n);
    + cdp->to += n;
    + }
    + n <<= 2;
    + cdp->offset += n;
    + cdp->len -= n;
    + return n;
    +}
    +
    +static inline int copy_bits_internal(struct ipath_devdata *dd,
    + struct copy_data_s *cdp, u8 *p,
    + unsigned *copyp, unsigned *offsetp,
    + unsigned *lenp, int do_csum)
    +{
    + unsigned copy = *copyp;
    + unsigned len = *lenp;
    + int ret = 1;
    +
    + if (copy > len)
    + copy = len;
    + *offsetp += copy;
    + len -= copy;
    + if (do_csum && !cdp->checksum_calc) {
    + unsigned int csum2;
    +
    + cdp->checksum_calc = 1;
    +
    + csum2 = csum_partial(p, copy, 0);
    + cdp->csum = csum_block_add(cdp->csum, csum2, cdp->pos);
    + cdp->pos += copy;
    + }
    + /*
    + * If the alignment buffer is not empty, fill it and write it
    + * out.
    + */
    + if (cdp->extra) {
    + if (cdp->extra == 4) {
    + if (copy_extra_dword(dd, cdp, 1))
    + goto done;
    + }
    + else while (copy != 0) {
    + cdp->u.buf[cdp->extra] = *p++;
    + copy--;
    + cdp->offset++;
    + cdp->len--;
    + if (++cdp->extra == 4) {
    + if (copy_extra_dword(dd, cdp, 1))
    + goto done;
    + break;
    + }
    + }
    + }
    +
    + while (copy >= 4) {
    + u32 n = copy_a_buffer(dd, cdp, p, copy >> 2, 1);
    + if (n == -1)
    + goto done;
    + p += n;
    + copy -= n;
    + }
    + /*
    + * Either cdp->extra is zero or copy is zero, which means that
    + * the loop here can't cause the alignment buffer to fill up.
    + */
    + while (copy != 0) {
    + cdp->u.buf[cdp->extra++] = *p++;
    + copy--;
    + cdp->offset++;
    + cdp->len--;
    + }
    +
    + if (do_csum)
    + cdp->checksum_calc = 0;
    +
    + if (len == 0)
    + goto done;
    +
    + ret = 0;
    +done:
    + *copyp = copy;
    + *lenp = len;
    + return ret;
    +}
    +
    +/**
    + * copy_and_maybe_csum_bits - copy data into the PIO buffer
    + * @dd: the infinipath device
    + * @skb: the source sk_buff
    + * @offset: the offset within the source
    + * @len: the len of the data to copy
    + * @cdp: the destination
    + * @do_csum: write a checksum if true
    + *
    + * Copy data out of one or a chain of sk_buffs, into the PIO buffer,
    + * generating the checksum as we go if do_csum is non-zero.
    + * Fragment an sk_buff into multiple IB packets if the amount of data
    + * is more than a single eager send.
    + * Offset and len are in bytes.
    + * Note that this function is recursive!
    + */
    +static void copy_and_maybe_csum_bits(struct ipath_devdata *dd,
    + const struct sk_buff *skb,
    + unsigned int offset,
    + unsigned int len,
    + struct copy_data_s *cdp,
    + int do_csum)
    +{
    + unsigned int start = skb_headlen(skb);
    + unsigned int i, copy;
    +
    + /* Copy header. */
    + copy = start - offset;
    + if ((int) copy > 0) {
    + u8 *p = skb->data + offset;
    +
    + if (copy_bits_internal(dd, cdp, p, &copy, &offset, &len,
    + do_csum))
    + goto done;
    + }
    +
    + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
    + skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
    + unsigned int end;
    +
    + end = start + frag->size;
    + copy = end - offset;
    + if ((int) copy > 0) {
    + u8 *vaddr = kmap_skb_frag(frag);
    + u8 *p = vaddr + frag->page_offset + offset - start;
    + int ret;
    +
    + ret = copy_bits_internal(dd, cdp, p, &copy,
    + &offset, &len, do_csum);
    +
    + kunmap_skb_frag(vaddr);
    +
    + if (ret)
    + goto done;
    + }
    + start = end;
    + }
    +
    + if (skb_shinfo(skb)->frag_list) {
    + struct sk_buff *list = skb_shinfo(skb)->frag_list;
    +
    + for (; list; list = list->next) {
    + unsigned int end;
    +
    + end = start + list->len;
    + copy = end - offset;
    + if ((int) copy > 0) {
    + if (copy > len)
    + copy = len;
    + copy_and_maybe_csum_bits(dd, list,
    + offset - start,
    + copy, cdp,
    + do_csum);
    + len -= copy;
    + if (cdp->error || len == 0)
    + goto done;
    + offset += copy;
    + }
    + start = end;
    + }
    + }
    + if (len)
    + cdp->error = -EFAULT;
    +done:
    + /* we have to flush after trigger word for correctness on some
    + * cpus or WC buffer can be written out of order; needed even
    + * if there was an error */
    + ipath_flush_wc();
    +}
    +
    +static inline void copy_and_csum_bits(struct ipath_devdata *dd,
    + const struct sk_buff *skb,
    + unsigned int offset,
    + unsigned int len,
    + struct copy_data_s *cdp)
    +{
    + copy_and_maybe_csum_bits(dd, skb, offset, len, cdp, 1);
    +}
    +
    +static inline void copy_bits(struct ipath_devdata *dd,
    + const struct sk_buff *skb,
    + unsigned int offset,
    + unsigned int len,
    + struct copy_data_s *cdp)
    +{
    + copy_and_maybe_csum_bits(dd, skb, offset, len, cdp, 0);
    +}
    +
    +/**
    + * ipath_layer_send_skb - layered sk_buff send
    + * @dd: the infinipath device
    + * @cdata: the data to send
    + *
    + * This is called by the ipath_ether module.
    + *
    + * Note that the header should have the unchanging parts
    + * initialized but the rest of the header is computed as needed in
    + * order to break up skb data buffers larger than the hardware MTU.
    + * In other words, the Linux network stack MTU can be larger than the
    + * hardware MTU.
    + */
    +int ipath_layer_send_skb(struct ipath_devdata *dd,
    + struct copy_data_s *cdata)
    +{
    + int ret = 0;
    + u16 vlsllnh;
    +
    + if (!(dd->ipath_flags & IPATH_RCVHDRSZ_SET)) {
    + dev_info(&dd->pcidev->dev, "send while not open\n");
    + ret = -EINVAL;
    + }
    + else if ((dd->ipath_flags & (IPATH_LINKUNK | IPATH_LINKDOWN)) ||
    + dd->ipath_lid == 0) {
    + /* lid check is for when sma hasn't yet configured */
    + ret = -ENETDOWN;
    + ipath_cdbg(VERBOSE, "send while not ready, mylid=%u, "
    + "flags=0x%x\n", dd->ipath_lid, dd->ipath_flags);
    + }
    + vlsllnh = *((u16 *) cdata->hdr);
    + if (vlsllnh != htons(IPS_LRH_BTH)) {
    + ipath_dbg("Warning: lrh[0] wrong (%x, not %x); "
    + "not sending\n", vlsllnh, htons(IPS_LRH_BTH));
    + ret = -EINVAL;
    + }
    + if (ret)
    + goto done;
    +
    + cdata->error = 0; /* clear last calls error */
    +
    + if (cdata->skb->ip_summed == CHECKSUM_HW) {
    + unsigned int csstart = cdata->skb->h.raw - cdata->skb->data;
    +
    + /*
    + * Computing the checksum is a bit tricky since if we
    + * fragment the packet, the fragment that should contain the
    + * checksum will have already been sent. The solution is to
    + * store the checksum in the header of the last fragment
    + * just before we write the last data word which triggers
    + * the last fragment to be sent. The receiver will check
    + * the header "tag" field, see that there is a checksum, and
    + * store the checksum back into the packet.
    + *
    + * Save the offset of the two byte checksum.
    + *
    + * Note that we have to add 2 to account for the two bytes
    + * of the ethernet address we stripped from the packet and
    + * put in the header.
    + */
    +
    + cdata->hdr->csum_offset = csstart + cdata->skb->csum + 2;
    +
    + if (cdata->offset < csstart)
    + copy_bits(dd, cdata->skb, cdata->offset,
    + csstart - cdata->offset, cdata);
    +
    + if (cdata->error) {
    + ret = cdata->error;
    + goto done;
    + }
    +
    + if (cdata->offset < cdata->skb->len)
    + copy_and_csum_bits(dd, cdata->skb, cdata->offset,
    + cdata->skb->len - cdata->offset,
    + cdata);
    +
    + if (cdata->error) {
    + ret = cdata->error;
    + goto done;
    + }
    +
    + if (cdata->extra) {
    + while (cdata->extra < 4)
    + cdata->u.buf[cdata->extra++] = 0;
    + (void)copy_extra_dword(dd, cdata, 1);
    + }
    + } else {
    + copy_bits(dd, cdata->skb, cdata->offset,
    + cdata->skb->len - cdata->offset, cdata);
    +
    + if (cdata->error) {
    + ret = cdata->error;
    + goto done;
    + }
    +
    + if (cdata->extra) {
    + while (cdata->extra < 4)
    + cdata->u.buf[cdata->extra++] = 0;
    + (void)copy_extra_dword(dd, cdata, 1);
    + }
    + }
    +
    + if (cdata->error) {
    + ret = cdata->error;
    + if (cdata->error != -EBUSY)
    + ipath_dev_err(dd, "layer_send copy_bits failed "
    + "with error %d\n", -ret);
    + }
    +
    + /* another ether packet sent */
    + ipath_stats.sps_ether_spkts++;
    +
    +done:
    + /*
    + * we have to flush after trigger word for correctness on
    + * some cpus or WC buffer can be written out of order; needed
    + * even if there was an error
    + */
    + ipath_flush_wc();
    + return ret;
    +}
    +
    +EXPORT_SYMBOL_GPL(ipath_layer_send_skb);
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/
    \
     
     \ /
      Last update: 2006-03-10 01:50    [W:0.061 / U:120.492 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site