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[SCSI] iscsi: bidi support at the generic libiscsi level
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- prepare the additional bidi_read rlength header.
- access the right scsi_in() and/or scsi_out() side of things.
  also for resid.
- Handle BIDI underflow overflow from target

Signed-off-by: Boaz Harrosh <[email protected]>
Reviewed-by: Pete Wyckoff <[email protected]>
Signed-off-by: Mike Christie <[email protected]>
Signed-off-by: James Bottomley <[email protected]>
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Boaz Harrosh authored and James Bottomley committed Apr 18, 2008
1 parent 38d1c06 commit c07d444
Showing 1 changed file with 70 additions and 15 deletions.
85 changes: 70 additions & 15 deletions drivers/scsi/libiscsi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -176,6 +176,31 @@ static int iscsi_prep_ecdb_ahs(struct iscsi_cmd_task *ctask)
return 0;
}

static int iscsi_prep_bidi_ahs(struct iscsi_cmd_task *ctask)
{
struct scsi_cmnd *sc = ctask->sc;
struct iscsi_rlength_ahdr *rlen_ahdr;
int rc;

rlen_ahdr = iscsi_next_hdr(ctask);
rc = iscsi_add_hdr(ctask, sizeof(*rlen_ahdr));
if (rc)
return rc;

rlen_ahdr->ahslength =
cpu_to_be16(sizeof(rlen_ahdr->read_length) +
sizeof(rlen_ahdr->reserved));
rlen_ahdr->ahstype = ISCSI_AHSTYPE_RLENGTH;
rlen_ahdr->reserved = 0;
rlen_ahdr->read_length = cpu_to_be32(scsi_in(sc)->length);

debug_scsi("bidi-in rlen_ahdr->read_length(%d) "
"rlen_ahdr->ahslength(%d)\n",
be32_to_cpu(rlen_ahdr->read_length),
be16_to_cpu(rlen_ahdr->ahslength));
return 0;
}

/**
* iscsi_prep_scsi_cmd_pdu - prep iscsi scsi cmd pdu
* @ctask: iscsi cmd task
Expand All @@ -200,7 +225,6 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
hdr->flags = ISCSI_ATTR_SIMPLE;
int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
hdr->itt = build_itt(ctask->itt, session->age);
hdr->data_length = cpu_to_be32(scsi_bufflen(sc));
hdr->cmdsn = cpu_to_be32(session->cmdsn);
session->cmdsn++;
hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
Expand All @@ -216,7 +240,15 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
memcpy(hdr->cdb, sc->cmnd, cmd_len);

ctask->imm_count = 0;
if (scsi_bidi_cmnd(sc)) {
hdr->flags |= ISCSI_FLAG_CMD_READ;
rc = iscsi_prep_bidi_ahs(ctask);
if (rc)
return rc;
}
if (sc->sc_data_direction == DMA_TO_DEVICE) {
unsigned out_len = scsi_out(sc)->length;
hdr->data_length = cpu_to_be32(out_len);
hdr->flags |= ISCSI_FLAG_CMD_WRITE;
/*
* Write counters:
Expand All @@ -237,19 +269,19 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
ctask->unsol_datasn = 0;

if (session->imm_data_en) {
if (scsi_bufflen(sc) >= session->first_burst)
if (out_len >= session->first_burst)
ctask->imm_count = min(session->first_burst,
conn->max_xmit_dlength);
else
ctask->imm_count = min(scsi_bufflen(sc),
ctask->imm_count = min(out_len,
conn->max_xmit_dlength);
hton24(hdr->dlength, ctask->imm_count);
} else
zero_data(hdr->dlength);

if (!session->initial_r2t_en) {
ctask->unsol_count = min((session->first_burst),
(scsi_bufflen(sc))) - ctask->imm_count;
ctask->unsol_count = min(session->first_burst, out_len)
- ctask->imm_count;
ctask->unsol_offset = ctask->imm_count;
}

Expand All @@ -259,6 +291,7 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
} else {
hdr->flags |= ISCSI_FLAG_CMD_FINAL;
zero_data(hdr->dlength);
hdr->data_length = cpu_to_be32(scsi_in(sc)->length);

if (sc->sc_data_direction == DMA_FROM_DEVICE)
hdr->flags |= ISCSI_FLAG_CMD_READ;
Expand All @@ -277,10 +310,12 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
return EIO;

conn->scsicmd_pdus_cnt++;
debug_scsi("iscsi prep [%s cid %d sc %p cdb 0x%x itt 0x%x len %d "
"cmdsn %d win %d]\n",
sc->sc_data_direction == DMA_TO_DEVICE ? "write" : "read",
conn->id, sc, sc->cmnd[0], ctask->itt, scsi_bufflen(sc),
debug_scsi("iscsi prep [%s cid %d sc %p cdb 0x%x itt 0x%x "
"len %d bidi_len %d cmdsn %d win %d]\n",
scsi_bidi_cmnd(sc) ? "bidirectional" :
sc->sc_data_direction == DMA_TO_DEVICE ? "write" : "read",
conn->id, sc, sc->cmnd[0], ctask->itt,
scsi_bufflen(sc), scsi_bidi_cmnd(sc) ? scsi_in(sc)->length : 0,
session->cmdsn, session->max_cmdsn - session->exp_cmdsn + 1);
return 0;
}
Expand Down Expand Up @@ -343,7 +378,12 @@ static void fail_command(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
conn->session->tt->cleanup_cmd_task(conn, ctask);

sc->result = err;
scsi_set_resid(sc, scsi_bufflen(sc));
if (!scsi_bidi_cmnd(sc))
scsi_set_resid(sc, scsi_bufflen(sc));
else {
scsi_out(sc)->resid = scsi_out(sc)->length;
scsi_in(sc)->resid = scsi_in(sc)->length;
}
if (conn->ctask == ctask)
conn->ctask = NULL;
/* release ref from queuecommand */
Expand Down Expand Up @@ -478,20 +518,30 @@ static void iscsi_scsi_cmd_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
min_t(uint16_t, senselen, SCSI_SENSE_BUFFERSIZE));
}

if (rhdr->flags & (ISCSI_FLAG_CMD_BIDI_UNDERFLOW |
ISCSI_FLAG_CMD_BIDI_OVERFLOW)) {
int res_count = be32_to_cpu(rhdr->bi_residual_count);

if (scsi_bidi_cmnd(sc) && res_count > 0 &&
(rhdr->flags & ISCSI_FLAG_CMD_BIDI_OVERFLOW ||
res_count <= scsi_in(sc)->length))
scsi_in(sc)->resid = res_count;
else
sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
}

if (rhdr->flags & (ISCSI_FLAG_CMD_UNDERFLOW |
ISCSI_FLAG_CMD_OVERFLOW)) {
int res_count = be32_to_cpu(rhdr->residual_count);

if (res_count > 0 &&
(rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
res_count <= scsi_bufflen(sc)))
/* write side for bidi or uni-io set_resid */
scsi_set_resid(sc, res_count);
else
sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
} else if (rhdr->flags & (ISCSI_FLAG_CMD_BIDI_UNDERFLOW |
ISCSI_FLAG_CMD_BIDI_OVERFLOW))
sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;

}
out:
debug_scsi("done [sc %lx res %d itt 0x%x]\n",
(long)sc, sc->result, ctask->itt);
Expand Down Expand Up @@ -1147,7 +1197,12 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
fault:
spin_unlock(&session->lock);
debug_scsi("iscsi: cmd 0x%x is not queued (%d)\n", sc->cmnd[0], reason);
scsi_set_resid(sc, scsi_bufflen(sc));
if (!scsi_bidi_cmnd(sc))
scsi_set_resid(sc, scsi_bufflen(sc));
else {
scsi_out(sc)->resid = scsi_out(sc)->length;
scsi_in(sc)->resid = scsi_in(sc)->length;
}
sc->scsi_done(sc);
spin_lock(host->host_lock);
return 0;
Expand Down

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