svc_rdma_marshal.c

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/*
 * Copyright (c) 2005-2006 Network Appliance, 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 BSD-type
 * 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.
 *
 *      Neither the name of the Network Appliance, Inc. nor the names of
 *      its contributors may be used to endorse or promote products
 *      derived from this software without specific prior written
 *      permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Author: Tom Tucker <[email protected]>
 */

#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/debug.h>
#include <asm/unaligned.h>
#include <linux/sunrpc/rpc_rdma.h>
#include <linux/sunrpc/svc_rdma.h>

#define RPCDBG_FACILITY RPCDBG_SVCXPRT

/*
 * Decodes a read chunk list. The expected format is as follows:
 *    descrim  : xdr_one
 *    position : u32 offset into XDR stream
 *    handle   : u32 RKEY
 *    . . .
 *  end-of-list: xdr_zero
 */
static u32 *decode_read_list(u32 *va, u32 *vaend)
{
    struct rpcrdma_read_chunk *ch = (struct rpcrdma_read_chunk *)va;

    while (ch->rc_discrim != xdr_zero) {
        if (((unsigned long)ch + sizeof(struct rpcrdma_read_chunk)) >
            (unsigned long)vaend) {
            dprintk("svcrdma: vaend=%p, ch=%p\n", vaend, ch);
            return NULL;
        }
        ch++;
    }
    return (u32 *)&ch->rc_position;
}

/*
 * Determine number of chunks and total bytes in chunk list. The chunk
 * list has already been verified to fit within the RPCRDMA header.
 */
void svc_rdma_rcl_chunk_counts(struct rpcrdma_read_chunk *ch,
                   int *ch_count, int *byte_count)
{
    /* compute the number of bytes represented by read chunks */
    *byte_count = 0;
    *ch_count = 0;
    for (; ch->rc_discrim != 0; ch++) {
        *byte_count = *byte_count + ntohl(ch->rc_target.rs_length);
        *ch_count = *ch_count + 1;
    }
}

/*
 * Decodes a write chunk list. The expected format is as follows:
 *    descrim  : xdr_one
 *    nchunks  : <count>
 *       handle   : u32 RKEY              ---+
 *       length   : u32 <len of segment>     |
 *       offset   : remove va                + <count>
 *       . . .                               |
 *                                        ---+
 */
static u32 *decode_write_list(u32 *va, u32 *vaend)
{
    int nchunks;

    struct rpcrdma_write_array *ary =
        (struct rpcrdma_write_array *)va;

    /* Check for not write-array */
    if (ary->wc_discrim == xdr_zero)
        return (u32 *)&ary->wc_nchunks;

    if ((unsigned long)ary + sizeof(struct rpcrdma_write_array) >
        (unsigned long)vaend) {
        dprintk("svcrdma: ary=%p, vaend=%p\n", ary, vaend);
        return NULL;
    }
    nchunks = ntohl(ary->wc_nchunks);
    if (((unsigned long)&ary->wc_array[0] +
         (sizeof(struct rpcrdma_write_chunk) * nchunks)) >
        (unsigned long)vaend) {
        dprintk("svcrdma: ary=%p, wc_nchunks=%d, vaend=%p\n",
            ary, nchunks, vaend);
        return NULL;
    }
    /*
     * rs_length is the 2nd 4B field in wc_target and taking its
     * address skips the list terminator
     */
    return (u32 *)&ary->wc_array[nchunks].wc_target.rs_length;
}

static u32 *decode_reply_array(u32 *va, u32 *vaend)
{
    int nchunks;
    struct rpcrdma_write_array *ary =
        (struct rpcrdma_write_array *)va;

    /* Check for no reply-array */
    if (ary->wc_discrim == xdr_zero)
        return (u32 *)&ary->wc_nchunks;

    if ((unsigned long)ary + sizeof(struct rpcrdma_write_array) >
        (unsigned long)vaend) {
        dprintk("svcrdma: ary=%p, vaend=%p\n", ary, vaend);
        return NULL;
    }
    nchunks = ntohl(ary->wc_nchunks);
    if (((unsigned long)&ary->wc_array[0] +
         (sizeof(struct rpcrdma_write_chunk) * nchunks)) >
        (unsigned long)vaend) {
        dprintk("svcrdma: ary=%p, wc_nchunks=%d, vaend=%p\n",
            ary, nchunks, vaend);
        return NULL;
    }
    return (u32 *)&ary->wc_array[nchunks];
}

int svc_rdma_xdr_decode_req(struct rpcrdma_msg **rdma_req,
                struct svc_rqst *rqstp)
{
    struct rpcrdma_msg *rmsgp = NULL;
    u32 *va;
    u32 *vaend;
    u32 hdr_len;

    rmsgp = (struct rpcrdma_msg *)rqstp->rq_arg.head[0].iov_base;

    /* Verify that there's enough bytes for header + something */
    if (rqstp->rq_arg.len <= RPCRDMA_HDRLEN_MIN) {
        dprintk("svcrdma: header too short = %d\n",
            rqstp->rq_arg.len);
        return -EINVAL;
    }

    /* Decode the header */
    rmsgp->rm_xid = ntohl(rmsgp->rm_xid);
    rmsgp->rm_vers = ntohl(rmsgp->rm_vers);
    rmsgp->rm_credit = ntohl(rmsgp->rm_credit);
    rmsgp->rm_type = ntohl(rmsgp->rm_type);

    if (rmsgp->rm_vers != RPCRDMA_VERSION)
        return -ENOSYS;

    /* Pull in the extra for the padded case and bump our pointer */
    if (rmsgp->rm_type == RDMA_MSGP) {
        int hdrlen;
        rmsgp->rm_body.rm_padded.rm_align =
            ntohl(rmsgp->rm_body.rm_padded.rm_align);
        rmsgp->rm_body.rm_padded.rm_thresh =
            ntohl(rmsgp->rm_body.rm_padded.rm_thresh);

        va = &rmsgp->rm_body.rm_padded.rm_pempty[4];
        rqstp->rq_arg.head[0].iov_base = va;
        hdrlen = (u32)((unsigned long)va - (unsigned long)rmsgp);
        rqstp->rq_arg.head[0].iov_len -= hdrlen;
        if (hdrlen > rqstp->rq_arg.len)
            return -EINVAL;
        return hdrlen;
    }

    /* The chunk list may contain either a read chunk list or a write
     * chunk list and a reply chunk list.
     */
    va = &rmsgp->rm_body.rm_chunks[0];
    vaend = (u32 *)((unsigned long)rmsgp + rqstp->rq_arg.len);
    va = decode_read_list(va, vaend);
    if (!va)
        return -EINVAL;
    va = decode_write_list(va, vaend);
    if (!va)
        return -EINVAL;
    va = decode_reply_array(va, vaend);
    if (!va)
        return -EINVAL;

    rqstp->rq_arg.head[0].iov_base = va;
    hdr_len = (unsigned long)va - (unsigned long)rmsgp;
    rqstp->rq_arg.head[0].iov_len -= hdr_len;

    *rdma_req = rmsgp;
    return hdr_len;
}

int svc_rdma_xdr_decode_deferred_req(struct svc_rqst *rqstp)
{
    struct rpcrdma_msg *rmsgp = NULL;
    struct rpcrdma_read_chunk *ch;
    struct rpcrdma_write_array *ary;
    u32 *va;
    u32 hdrlen;

    dprintk("svcrdma: processing deferred RDMA header on rqstp=%p\n",
        rqstp);
    rmsgp = (struct rpcrdma_msg *)rqstp->rq_arg.head[0].iov_base;

    /* Pull in the extra for the padded case and bump our pointer */
    if (rmsgp->rm_type == RDMA_MSGP) {
        va = &rmsgp->rm_body.rm_padded.rm_pempty[4];
        rqstp->rq_arg.head[0].iov_base = va;
        hdrlen = (u32)((unsigned long)va - (unsigned long)rmsgp);
        rqstp->rq_arg.head[0].iov_len -= hdrlen;
        return hdrlen;
    }

    /*
     * Skip all chunks to find RPC msg. These were previously processed
     */
    va = &rmsgp->rm_body.rm_chunks[0];

    /* Skip read-list */
    for (ch = (struct rpcrdma_read_chunk *)va;
         ch->rc_discrim != xdr_zero; ch++);
    va = (u32 *)&ch->rc_position;

    /* Skip write-list */
    ary = (struct rpcrdma_write_array *)va;
    if (ary->wc_discrim == xdr_zero)
        va = (u32 *)&ary->wc_nchunks;
    else
        /*
         * rs_length is the 2nd 4B field in wc_target and taking its
         * address skips the list terminator
         */
        va = (u32 *)&ary->wc_array[ary->wc_nchunks].wc_target.rs_length;

    /* Skip reply-array */
    ary = (struct rpcrdma_write_array *)va;
    if (ary->wc_discrim == xdr_zero)
        va = (u32 *)&ary->wc_nchunks;
    else
        va = (u32 *)&ary->wc_array[ary->wc_nchunks];

    rqstp->rq_arg.head[0].iov_base = va;
    hdrlen = (unsigned long)va - (unsigned long)rmsgp;
    rqstp->rq_arg.head[0].iov_len -= hdrlen;

    return hdrlen;
}

int svc_rdma_xdr_encode_error(struct svcxprt_rdma *xprt,
                  struct rpcrdma_msg *rmsgp,
                  enum rpcrdma_errcode err, u32 *va)
{
    u32 *startp = va;

    *va++ = htonl(rmsgp->rm_xid);
    *va++ = htonl(rmsgp->rm_vers);
    *va++ = htonl(xprt->sc_max_requests);
    *va++ = htonl(RDMA_ERROR);
    *va++ = htonl(err);
    if (err == ERR_VERS) {
        *va++ = htonl(RPCRDMA_VERSION);
        *va++ = htonl(RPCRDMA_VERSION);
    }

    return (int)((unsigned long)va - (unsigned long)startp);
}

int svc_rdma_xdr_get_reply_hdr_len(struct rpcrdma_msg *rmsgp)
{
    struct rpcrdma_write_array *wr_ary;

    /* There is no read-list in a reply */

    /* skip write list */
    wr_ary = (struct rpcrdma_write_array *)
        &rmsgp->rm_body.rm_chunks[1];
    if (wr_ary->wc_discrim)
        wr_ary = (struct rpcrdma_write_array *)
            &wr_ary->wc_array[ntohl(wr_ary->wc_nchunks)].
            wc_target.rs_length;
    else
        wr_ary = (struct rpcrdma_write_array *)
            &wr_ary->wc_nchunks;

    /* skip reply array */
    if (wr_ary->wc_discrim)
        wr_ary = (struct rpcrdma_write_array *)
            &wr_ary->wc_array[ntohl(wr_ary->wc_nchunks)];
    else
        wr_ary = (struct rpcrdma_write_array *)
            &wr_ary->wc_nchunks;

    return (unsigned long) wr_ary - (unsigned long) rmsgp;
}

void svc_rdma_xdr_encode_write_list(struct rpcrdma_msg *rmsgp, int chunks)
{
    struct rpcrdma_write_array *ary;

    /* no read-list */
    rmsgp->rm_body.rm_chunks[0] = xdr_zero;

    /* write-array discrim */
    ary = (struct rpcrdma_write_array *)
        &rmsgp->rm_body.rm_chunks[1];
    ary->wc_discrim = xdr_one;
    ary->wc_nchunks = htonl(chunks);

    /* write-list terminator */
    ary->wc_array[chunks].wc_target.rs_handle = xdr_zero;

    /* reply-array discriminator */
    ary->wc_array[chunks].wc_target.rs_length = xdr_zero;
}

void svc_rdma_xdr_encode_reply_array(struct rpcrdma_write_array *ary,
                 int chunks)
{
    ary->wc_discrim = xdr_one;
    ary->wc_nchunks = htonl(chunks);
}

void svc_rdma_xdr_encode_array_chunk(struct rpcrdma_write_array *ary,
                     int chunk_no,
                     __be32 rs_handle,
                     __be64 rs_offset,
                     u32 write_len)
{
    struct rpcrdma_segment *seg = &ary->wc_array[chunk_no].wc_target;
    seg->rs_handle = rs_handle;
    seg->rs_offset = rs_offset;
    seg->rs_length = htonl(write_len);
}

void svc_rdma_xdr_encode_reply_header(struct svcxprt_rdma *xprt,
                  struct rpcrdma_msg *rdma_argp,
                  struct rpcrdma_msg *rdma_resp,
                  enum rpcrdma_proc rdma_type)
{
    rdma_resp->rm_xid = htonl(rdma_argp->rm_xid);
    rdma_resp->rm_vers = htonl(rdma_argp->rm_vers);
    rdma_resp->rm_credit = htonl(xprt->sc_max_requests);
    rdma_resp->rm_type = htonl(rdma_type);

    /* Encode <nul> chunks lists */
    rdma_resp->rm_body.rm_chunks[0] = xdr_zero;
    rdma_resp->rm_body.rm_chunks[1] = xdr_zero;
    rdma_resp->rm_body.rm_chunks[2] = xdr_zero;
}