message.c

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/*
 * Copyright (c) 2006 Oracle.  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.
 *
 */
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/export.h>

#include "rds.h"

static unsigned int rds_exthdr_size[__RDS_EXTHDR_MAX] = {
[RDS_EXTHDR_NONE]   = 0,
[RDS_EXTHDR_VERSION]    = sizeof(struct rds_ext_header_version),
[RDS_EXTHDR_RDMA]   = sizeof(struct rds_ext_header_rdma),
[RDS_EXTHDR_RDMA_DEST]  = sizeof(struct rds_ext_header_rdma_dest),
};


void rds_message_addref(struct rds_message *rm)
{
    rdsdebug("addref rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));
    atomic_inc(&rm->m_refcount);
}
EXPORT_SYMBOL_GPL(rds_message_addref);

/*
 * This relies on dma_map_sg() not touching sg[].page during merging.
 */
static void rds_message_purge(struct rds_message *rm)
{
    unsigned long i;

    if (unlikely(test_bit(RDS_MSG_PAGEVEC, &rm->m_flags)))
        return;

    for (i = 0; i < rm->data.op_nents; i++) {
        rdsdebug("putting data page %p\n", (void *)sg_page(&rm->data.op_sg[i]));
        /* XXX will have to put_page for page refs */
        __free_page(sg_page(&rm->data.op_sg[i]));
    }
    rm->data.op_nents = 0;

    if (rm->rdma.op_active)
        rds_rdma_free_op(&rm->rdma);
    if (rm->rdma.op_rdma_mr)
        rds_mr_put(rm->rdma.op_rdma_mr);

    if (rm->atomic.op_active)
        rds_atomic_free_op(&rm->atomic);
    if (rm->atomic.op_rdma_mr)
        rds_mr_put(rm->atomic.op_rdma_mr);
}

void rds_message_put(struct rds_message *rm)
{
    rdsdebug("put rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));
    if (atomic_read(&rm->m_refcount) == 0) {
printk(KERN_CRIT "danger refcount zero on %p\n", rm);
WARN_ON(1);
    }
    if (atomic_dec_and_test(&rm->m_refcount)) {
        BUG_ON(!list_empty(&rm->m_sock_item));
        BUG_ON(!list_empty(&rm->m_conn_item));
        rds_message_purge(rm);

        kfree(rm);
    }
}
EXPORT_SYMBOL_GPL(rds_message_put);

void rds_message_populate_header(struct rds_header *hdr, __be16 sport,
                 __be16 dport, u64 seq)
{
    hdr->h_flags = 0;
    hdr->h_sport = sport;
    hdr->h_dport = dport;
    hdr->h_sequence = cpu_to_be64(seq);
    hdr->h_exthdr[0] = RDS_EXTHDR_NONE;
}
EXPORT_SYMBOL_GPL(rds_message_populate_header);

int rds_message_add_extension(struct rds_header *hdr, unsigned int type,
                  const void *data, unsigned int len)
{
    unsigned int ext_len = sizeof(u8) + len;
    unsigned char *dst;

    /* For now, refuse to add more than one extension header */
    if (hdr->h_exthdr[0] != RDS_EXTHDR_NONE)
        return 0;

    if (type >= __RDS_EXTHDR_MAX || len != rds_exthdr_size[type])
        return 0;

    if (ext_len >= RDS_HEADER_EXT_SPACE)
        return 0;
    dst = hdr->h_exthdr;

    *dst++ = type;
    memcpy(dst, data, len);

    dst[len] = RDS_EXTHDR_NONE;
    return 1;
}
EXPORT_SYMBOL_GPL(rds_message_add_extension);

/*
 * If a message has extension headers, retrieve them here.
 * Call like this:
 *
 * unsigned int pos = 0;
 *
 * while (1) {
 *  buflen = sizeof(buffer);
 *  type = rds_message_next_extension(hdr, &pos, buffer, &buflen);
 *  if (type == RDS_EXTHDR_NONE)
 *      break;
 *  ...
 * }
 */
int rds_message_next_extension(struct rds_header *hdr,
        unsigned int *pos, void *buf, unsigned int *buflen)
{
    unsigned int offset, ext_type, ext_len;
    u8 *src = hdr->h_exthdr;

    offset = *pos;
    if (offset >= RDS_HEADER_EXT_SPACE)
        goto none;

    /* Get the extension type and length. For now, the
     * length is implied by the extension type. */
    ext_type = src[offset++];

    if (ext_type == RDS_EXTHDR_NONE || ext_type >= __RDS_EXTHDR_MAX)
        goto none;
    ext_len = rds_exthdr_size[ext_type];
    if (offset + ext_len > RDS_HEADER_EXT_SPACE)
        goto none;

    *pos = offset + ext_len;
    if (ext_len < *buflen)
        *buflen = ext_len;
    memcpy(buf, src + offset, *buflen);
    return ext_type;

none:
    *pos = RDS_HEADER_EXT_SPACE;
    *buflen = 0;
    return RDS_EXTHDR_NONE;
}

int rds_message_add_rdma_dest_extension(struct rds_header *hdr, u32 r_key, u32 offset)
{
    struct rds_ext_header_rdma_dest ext_hdr;

    ext_hdr.h_rdma_rkey = cpu_to_be32(r_key);
    ext_hdr.h_rdma_offset = cpu_to_be32(offset);
    return rds_message_add_extension(hdr, RDS_EXTHDR_RDMA_DEST, &ext_hdr, sizeof(ext_hdr));
}
EXPORT_SYMBOL_GPL(rds_message_add_rdma_dest_extension);

/*
 * Each rds_message is allocated with extra space for the scatterlist entries
 * rds ops will need. This is to minimize memory allocation count. Then, each rds op
 * can grab SGs when initializing its part of the rds_message.
 */
struct rds_message *rds_message_alloc(unsigned int extra_len, gfp_t gfp)
{
    struct rds_message *rm;

    rm = kzalloc(sizeof(struct rds_message) + extra_len, gfp);
    if (!rm)
        goto out;

    rm->m_used_sgs = 0;
    rm->m_total_sgs = extra_len / sizeof(struct scatterlist);

    atomic_set(&rm->m_refcount, 1);
    INIT_LIST_HEAD(&rm->m_sock_item);
    INIT_LIST_HEAD(&rm->m_conn_item);
    spin_lock_init(&rm->m_rs_lock);
    init_waitqueue_head(&rm->m_flush_wait);

out:
    return rm;
}

/*
 * RDS ops use this to grab SG entries from the rm's sg pool.
 */
struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents)
{
    struct scatterlist *sg_first = (struct scatterlist *) &rm[1];
    struct scatterlist *sg_ret;

    WARN_ON(rm->m_used_sgs + nents > rm->m_total_sgs);
    WARN_ON(!nents);

    if (rm->m_used_sgs + nents > rm->m_total_sgs)
        return NULL;

    sg_ret = &sg_first[rm->m_used_sgs];
    sg_init_table(sg_ret, nents);
    rm->m_used_sgs += nents;

    return sg_ret;
}

struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned int total_len)
{
    struct rds_message *rm;
    unsigned int i;
    int num_sgs = ceil(total_len, PAGE_SIZE);
    int extra_bytes = num_sgs * sizeof(struct scatterlist);

    rm = rds_message_alloc(extra_bytes, GFP_NOWAIT);
    if (!rm)
        return ERR_PTR(-ENOMEM);

    set_bit(RDS_MSG_PAGEVEC, &rm->m_flags);
    rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
    rm->data.op_nents = ceil(total_len, PAGE_SIZE);
    rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs);
    if (!rm->data.op_sg) {
        rds_message_put(rm);
        return ERR_PTR(-ENOMEM);
    }

    for (i = 0; i < rm->data.op_nents; ++i) {
        sg_set_page(&rm->data.op_sg[i],
                virt_to_page(page_addrs[i]),
                PAGE_SIZE, 0);
    }

    return rm;
}

int rds_message_copy_from_user(struct rds_message *rm, struct iovec *first_iov,
                           size_t total_len)
{
    unsigned long to_copy;
    unsigned long iov_off;
    unsigned long sg_off;
    struct iovec *iov;
    struct scatterlist *sg;
    int ret = 0;

    rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);

    /*
     * now allocate and copy in the data payload.
     */
    sg = rm->data.op_sg;
    iov = first_iov;
    iov_off = 0;
    sg_off = 0; /* Dear gcc, sg->page will be null from kzalloc. */

    while (total_len) {
        if (!sg_page(sg)) {
            ret = rds_page_remainder_alloc(sg, total_len,
                               GFP_HIGHUSER);
            if (ret)
                goto out;
            rm->data.op_nents++;
            sg_off = 0;
        }

        while (iov_off == iov->iov_len) {
            iov_off = 0;
            iov++;
        }

        to_copy = min(iov->iov_len - iov_off, sg->length - sg_off);
        to_copy = min_t(size_t, to_copy, total_len);

        rdsdebug("copying %lu bytes from user iov [%p, %zu] + %lu to "
             "sg [%p, %u, %u] + %lu\n",
             to_copy, iov->iov_base, iov->iov_len, iov_off,
             (void *)sg_page(sg), sg->offset, sg->length, sg_off);

        ret = rds_page_copy_from_user(sg_page(sg), sg->offset + sg_off,
                          iov->iov_base + iov_off,
                          to_copy);
        if (ret)
            goto out;

        iov_off += to_copy;
        total_len -= to_copy;
        sg_off += to_copy;

        if (sg_off == sg->length)
            sg++;
    }

out:
    return ret;
}

int rds_message_inc_copy_to_user(struct rds_incoming *inc,
                 struct iovec *first_iov, size_t size)
{
    struct rds_message *rm;
    struct iovec *iov;
    struct scatterlist *sg;
    unsigned long to_copy;
    unsigned long iov_off;
    unsigned long vec_off;
    int copied;
    int ret;
    u32 len;

    rm = container_of(inc, struct rds_message, m_inc);
    len = be32_to_cpu(rm->m_inc.i_hdr.h_len);

    iov = first_iov;
    iov_off = 0;
    sg = rm->data.op_sg;
    vec_off = 0;
    copied = 0;

    while (copied < size && copied < len) {
        while (iov_off == iov->iov_len) {
            iov_off = 0;
            iov++;
        }

        to_copy = min(iov->iov_len - iov_off, sg->length - vec_off);
        to_copy = min_t(size_t, to_copy, size - copied);
        to_copy = min_t(unsigned long, to_copy, len - copied);

        rdsdebug("copying %lu bytes to user iov [%p, %zu] + %lu to "
             "sg [%p, %u, %u] + %lu\n",
             to_copy, iov->iov_base, iov->iov_len, iov_off,
             sg_page(sg), sg->offset, sg->length, vec_off);

        ret = rds_page_copy_to_user(sg_page(sg), sg->offset + vec_off,
                        iov->iov_base + iov_off,
                        to_copy);
        if (ret) {
            copied = ret;
            break;
        }

        iov_off += to_copy;
        vec_off += to_copy;
        copied += to_copy;

        if (vec_off == sg->length) {
            vec_off = 0;
            sg++;
        }
    }

    return copied;
}

/*
 * If the message is still on the send queue, wait until the transport
 * is done with it. This is particularly important for RDMA operations.
 */
void rds_message_wait(struct rds_message *rm)
{
    wait_event_interruptible(rm->m_flush_wait,
            !test_bit(RDS_MSG_MAPPED, &rm->m_flags));
}

void rds_message_unmapped(struct rds_message *rm)
{
    clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
    wake_up_interruptible(&rm->m_flush_wait);
}
EXPORT_SYMBOL_GPL(rds_message_unmapped);