tfc_io.c

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/*
 * Copyright (c) 2010 Cisco Systems, Inc.
 *
 * Portions based on tcm_loop_fabric_scsi.c and libfc/fc_fcp.c
 *
 * Copyright (c) 2007 Intel Corporation. All rights reserved.
 * Copyright (c) 2008 Red Hat, Inc.  All rights reserved.
 * Copyright (c) 2008 Mike Christie
 * Copyright (c) 2009 Rising Tide, Inc.
 * Copyright (c) 2009 Linux-iSCSI.org
 * Copyright (c) 2009 Nicholas A. Bellinger <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 */

/* XXX TBD some includes may be extraneous */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/utsname.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/configfs.h>
#include <linux/ctype.h>
#include <linux/hash.h>
#include <linux/ratelimit.h>
#include <asm/unaligned.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/libfc.h>
#include <scsi/fc_encode.h>

#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/target_core_configfs.h>
#include <target/configfs_macros.h>

#include "tcm_fc.h"

/*
 * Deliver read data back to initiator.
 * XXX TBD handle resource problems later.
 */
int ft_queue_data_in(struct se_cmd *se_cmd)
{
    struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
    struct fc_frame *fp = NULL;
    struct fc_exch *ep;
    struct fc_lport *lport;
    struct scatterlist *sg = NULL;
    size_t remaining;
    u32 f_ctl = FC_FC_EX_CTX | FC_FC_REL_OFF;
    u32 mem_off = 0;
    u32 fh_off = 0;
    u32 frame_off = 0;
    size_t frame_len = 0;
    size_t mem_len = 0;
    size_t tlen;
    size_t off_in_page;
    struct page *page = NULL;
    int use_sg;
    int error;
    void *page_addr;
    void *from;
    void *to = NULL;

    if (cmd->aborted)
        return 0;
    ep = fc_seq_exch(cmd->seq);
    lport = ep->lp;
    cmd->seq = lport->tt.seq_start_next(cmd->seq);

    remaining = se_cmd->data_length;

    /*
     * Setup to use first mem list entry, unless no data.
     */
    BUG_ON(remaining && !se_cmd->t_data_sg);
    if (remaining) {
        sg = se_cmd->t_data_sg;
        mem_len = sg->length;
        mem_off = sg->offset;
        page = sg_page(sg);
    }

    /* no scatter/gather in skb for odd word length due to fc_seq_send() */
    use_sg = !(remaining % 4);

    while (remaining) {
        if (!mem_len) {
            sg = sg_next(sg);
            mem_len = min((size_t)sg->length, remaining);
            mem_off = sg->offset;
            page = sg_page(sg);
        }
        if (!frame_len) {
            /*
             * If lport's has capability of Large Send Offload LSO)
             * , then allow 'frame_len' to be as big as 'lso_max'
             * if indicated transfer length is >= lport->lso_max
             */
            frame_len = (lport->seq_offload) ? lport->lso_max :
                              cmd->sess->max_frame;
            frame_len = min(frame_len, remaining);
            fp = fc_frame_alloc(lport, use_sg ? 0 : frame_len);
            if (!fp)
                return -ENOMEM;
            to = fc_frame_payload_get(fp, 0);
            fh_off = frame_off;
            frame_off += frame_len;
            /*
             * Setup the frame's max payload which is used by base
             * driver to indicate HW about max frame size, so that
             * HW can do fragmentation appropriately based on
             * "gso_max_size" of underline netdev.
             */
            fr_max_payload(fp) = cmd->sess->max_frame;
        }
        tlen = min(mem_len, frame_len);

        if (use_sg) {
            off_in_page = mem_off;
            BUG_ON(!page);
            get_page(page);
            skb_fill_page_desc(fp_skb(fp),
                       skb_shinfo(fp_skb(fp))->nr_frags,
                       page, off_in_page, tlen);
            fr_len(fp) += tlen;
            fp_skb(fp)->data_len += tlen;
            fp_skb(fp)->truesize +=
                    PAGE_SIZE << compound_order(page);
        } else {
            BUG_ON(!page);
            from = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
            page_addr = from;
            from += mem_off & ~PAGE_MASK;
            tlen = min(tlen, (size_t)(PAGE_SIZE -
                        (mem_off & ~PAGE_MASK)));
            memcpy(to, from, tlen);
            kunmap_atomic(page_addr);
            to += tlen;
        }

        mem_off += tlen;
        mem_len -= tlen;
        frame_len -= tlen;
        remaining -= tlen;

        if (frame_len &&
            (skb_shinfo(fp_skb(fp))->nr_frags < FC_FRAME_SG_LEN))
            continue;
        if (!remaining)
            f_ctl |= FC_FC_END_SEQ;
        fc_fill_fc_hdr(fp, FC_RCTL_DD_SOL_DATA, ep->did, ep->sid,
                   FC_TYPE_FCP, f_ctl, fh_off);
        error = lport->tt.seq_send(lport, cmd->seq, fp);
        if (error) {
            /* XXX For now, initiator will retry */
            pr_err_ratelimited("%s: Failed to send frame %p, "
                        "xid <0x%x>, remaining %zu, "
                        "lso_max <0x%x>\n",
                        __func__, fp, ep->xid,
                        remaining, lport->lso_max);
        }
    }
    return ft_queue_status(se_cmd);
}

static void ft_execute_work(struct work_struct *work)
{
    struct ft_cmd *cmd = container_of(work, struct ft_cmd, work);

    target_execute_cmd(&cmd->se_cmd);
}

/*
 * Receive write data frame.
 */
void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame *fp)
{
    struct se_cmd *se_cmd = &cmd->se_cmd;
    struct fc_seq *seq = cmd->seq;
    struct fc_exch *ep;
    struct fc_lport *lport;
    struct fc_frame_header *fh;
    struct scatterlist *sg = NULL;
    u32 mem_off = 0;
    u32 rel_off;
    size_t frame_len;
    size_t mem_len = 0;
    size_t tlen;
    struct page *page = NULL;
    void *page_addr;
    void *from;
    void *to;
    u32 f_ctl;
    void *buf;

    fh = fc_frame_header_get(fp);
    if (!(ntoh24(fh->fh_f_ctl) & FC_FC_REL_OFF))
        goto drop;

    f_ctl = ntoh24(fh->fh_f_ctl);
    ep = fc_seq_exch(seq);
    lport = ep->lp;
    if (cmd->was_ddp_setup) {
        BUG_ON(!ep);
        BUG_ON(!lport);
        /*
         * Since DDP (Large Rx offload) was setup for this request,
         * payload is expected to be copied directly to user buffers.
         */
        buf = fc_frame_payload_get(fp, 1);
        if (buf)
            pr_err("%s: xid 0x%x, f_ctl 0x%x, cmd->sg %p, "
                "cmd->sg_cnt 0x%x. DDP was setup"
                " hence not expected to receive frame with "
                "payload, Frame will be dropped if"
                "'Sequence Initiative' bit in f_ctl is"
                "not set\n", __func__, ep->xid, f_ctl,
                se_cmd->t_data_sg, se_cmd->t_data_nents);
        /*
         * Invalidate HW DDP context if it was setup for respective
         * command. Invalidation of HW DDP context is requited in both
         * situation (success and error).
         */
        ft_invl_hw_context(cmd);

        /*
         * If "Sequence Initiative (TSI)" bit set in f_ctl, means last
         * write data frame is received successfully where payload is
         * posted directly to user buffer and only the last frame's
         * header is posted in receive queue.
         *
         * If "Sequence Initiative (TSI)" bit is not set, means error
         * condition w.r.t. DDP, hence drop the packet and let explict
         * ABORTS from other end of exchange timer trigger the recovery.
         */
        if (f_ctl & FC_FC_SEQ_INIT)
            goto last_frame;
        else
            goto drop;
    }

    rel_off = ntohl(fh->fh_parm_offset);
    frame_len = fr_len(fp);
    if (frame_len <= sizeof(*fh))
        goto drop;
    frame_len -= sizeof(*fh);
    from = fc_frame_payload_get(fp, 0);
    if (rel_off >= se_cmd->data_length)
        goto drop;
    if (frame_len + rel_off > se_cmd->data_length)
        frame_len = se_cmd->data_length - rel_off;

    /*
     * Setup to use first mem list entry, unless no data.
     */
    BUG_ON(frame_len && !se_cmd->t_data_sg);
    if (frame_len) {
        sg = se_cmd->t_data_sg;
        mem_len = sg->length;
        mem_off = sg->offset;
        page = sg_page(sg);
    }

    while (frame_len) {
        if (!mem_len) {
            sg = sg_next(sg);
            mem_len = sg->length;
            mem_off = sg->offset;
            page = sg_page(sg);
        }
        if (rel_off >= mem_len) {
            rel_off -= mem_len;
            mem_len = 0;
            continue;
        }
        mem_off += rel_off;
        mem_len -= rel_off;
        rel_off = 0;

        tlen = min(mem_len, frame_len);

        to = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
        page_addr = to;
        to += mem_off & ~PAGE_MASK;
        tlen = min(tlen, (size_t)(PAGE_SIZE -
                      (mem_off & ~PAGE_MASK)));
        memcpy(to, from, tlen);
        kunmap_atomic(page_addr);

        from += tlen;
        frame_len -= tlen;
        mem_off += tlen;
        mem_len -= tlen;
        cmd->write_data_len += tlen;
    }
last_frame:
    if (cmd->write_data_len == se_cmd->data_length) {
        INIT_WORK(&cmd->work, ft_execute_work);
        queue_work(cmd->sess->tport->tpg->workqueue, &cmd->work);
    }
drop:
    fc_frame_free(fp);
}

/*
 * Handle and cleanup any HW specific resources if
 * received ABORTS, errors, timeouts.
 */
void ft_invl_hw_context(struct ft_cmd *cmd)
{
    struct fc_seq *seq;
    struct fc_exch *ep = NULL;
    struct fc_lport *lport = NULL;

    BUG_ON(!cmd);
    seq = cmd->seq;

    /* Cleanup the DDP context in HW if DDP was setup */
    if (cmd->was_ddp_setup && seq) {
        ep = fc_seq_exch(seq);
        if (ep) {
            lport = ep->lp;
            if (lport && (ep->xid <= lport->lro_xid))
                /*
                 * "ddp_done" trigger invalidation of HW
                 * specific DDP context
                 */
                cmd->write_data_len = lport->tt.ddp_done(lport,
                                      ep->xid);

                /*
                 * Resetting same variable to indicate HW's
                 * DDP context has been invalidated to avoid
                 * re_invalidation of same context (context is
                 * identified using ep->xid)
                 */
                cmd->was_ddp_setup = 0;
        }
    }
}