/*
* 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;
if (se_cmd->scsi_status == SAM_STAT_TASK_SET_FULL)
goto queue_status;
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) {
struct fc_seq *seq = cmd->seq;
if (!seq) {
pr_debug("%s: Command aborted, xid 0x%x\n",
__func__, ep->xid);
break;
}
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, seq, fp);
if (error) {
pr_info_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);
/*
* Go ahead and set TASK_SET_FULL status ignoring the
* rest of the DataIN, and immediately attempt to
* send the response via ft_queue_status() in order
* to notify the initiator that it should reduce it's
* per LUN queue_depth.
*/
se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
break;
}
}
queue_status:
return ft_queue_status(se_cmd);
}
/*
* Send read data back to initiator.
*/
int ft_send_read_data(struct scst_cmd *cmd)
{
struct ft_cmd *fcmd;
struct fc_frame *fp = NULL;
struct fc_exch *ep;
struct fc_lport *lport;
size_t remaining;
u32 fh_off = 0;
u32 frame_off;
size_t frame_len = 0;
size_t mem_len;
u32 mem_off;
size_t tlen;
struct page *page;
int use_sg;
int error;
void *to = NULL;
u8 *from = NULL;
int loop_limit = 10000;
fcmd = scst_cmd_get_tgt_priv(cmd);
ep = fc_seq_exch(fcmd->seq);
lport = ep->lp;
frame_off = fcmd->read_data_len;
tlen = scst_cmd_get_resp_data_len(cmd);
FT_IO_DBG("oid %x oxid %x resp_len %zd frame_off %u\n",
ep->oid, ep->oxid, tlen, frame_off);
if (tlen <= frame_off)
return SCST_TGT_RES_SUCCESS;
remaining = tlen - frame_off;
if (remaining > UINT_MAX)
FT_ERR("oid %x oxid %x resp_len %zd frame_off %u\n",
ep->oid, ep->oxid, tlen, frame_off);
mem_len = scst_get_buf_first(cmd, &from);
mem_off = 0;
if (!mem_len) {
FT_IO_DBG("mem_len 0\n");
return SCST_TGT_RES_SUCCESS;
}
FT_IO_DBG("sid %x oxid %x mem_len %zd frame_off %u remaining %zd\n",
ep->sid, ep->oxid, mem_len, frame_off, remaining);
/*
* If we've already transferred some of the data, skip through
* the buffer over the data already sent and continue with the
* same sequence. Otherwise, get a new sequence for the data.
*/
if (frame_off) {
tlen = frame_off;
while (mem_len <= tlen) {
tlen -= mem_len;
scst_put_buf(cmd, from);
mem_len = scst_get_buf_next(cmd, &from);
if (!mem_len)
return SCST_TGT_RES_SUCCESS;
}
mem_len -= tlen;
mem_off = tlen;
} else
fcmd->seq = lport->tt.seq_start_next(fcmd->seq);
/* no scatter/gather in skb for odd word length due to fc_seq_send() */
use_sg = !(remaining % 4) && lport->sg_supp;
while (remaining) {
if (!loop_limit) {
FT_ERR("hit loop limit. remaining %zx mem_len %zx "
"frame_len %zx tlen %zx\n",
remaining, mem_len, frame_len, tlen);
break;
}
loop_limit--;
if (!mem_len) {
scst_put_buf(cmd, from);
mem_len = scst_get_buf_next(cmd, &from);
mem_off = 0;
if (!mem_len) {
FT_ERR("mem_len 0 from get_buf_next\n");
break;
}
}
if (!frame_len) {
frame_len = fcmd->max_lso_payload;
frame_len = min(frame_len, remaining);
fp = fc_frame_alloc(lport, use_sg ? 0 : frame_len);
if (!fp) {
FT_IO_DBG("frame_alloc failed. "
"use_sg %d frame_len %zd\n",
use_sg, frame_len);
break;
}
fr_max_payload(fp) = fcmd->max_payload;
to = fc_frame_payload_get(fp, 0);
fh_off = frame_off;
}
tlen = min(mem_len, frame_len);
BUG_ON(!tlen);
BUG_ON(tlen > remaining);
BUG_ON(tlen > mem_len);
BUG_ON(tlen > frame_len);
if (use_sg) {
page = virt_to_page(from + mem_off);
get_page(page);
tlen = min_t(size_t, tlen,
PAGE_SIZE - (mem_off & ~PAGE_MASK));
skb_fill_page_desc(fp_skb(fp),
skb_shinfo(fp_skb(fp))->nr_frags,
page, offset_in_page(from + mem_off),
tlen);
fr_len(fp) += tlen;
fp_skb(fp)->data_len += tlen;
fp_skb(fp)->truesize +=
PAGE_SIZE << compound_order(page);
frame_len -= tlen;
if (skb_shinfo(fp_skb(fp))->nr_frags >= FC_FRAME_SG_LEN)
frame_len = 0;
} else {
memcpy(to, from + mem_off, tlen);
to += tlen;
frame_len -= tlen;
}
mem_len -= tlen;
mem_off += tlen;
remaining -= tlen;
frame_off += tlen;
if (frame_len)
continue;
fc_fill_fc_hdr(fp, FC_RCTL_DD_SOL_DATA, ep->did, ep->sid,
FC_TYPE_FCP,
remaining ? (FC_FC_EX_CTX | FC_FC_REL_OFF) :
(FC_FC_EX_CTX | FC_FC_REL_OFF | FC_FC_END_SEQ),
fh_off);
error = lport->tt.seq_send(lport, fcmd->seq, fp);
if (error) {
WARN_ON(1);
/* XXX For now, initiator will retry */
} else
fcmd->read_data_len = frame_off;
}
if (mem_len)
scst_put_buf(cmd, from);
if (remaining) {
FT_IO_DBG("remaining read data %zd\n", remaining);
return SCST_TGT_RES_QUEUE_FULL;
}
return SCST_TGT_RES_SUCCESS;
}
