[SCSI] libfc: add support of large receive offload by ddp in fc_fcp
When LLD supports direct data placement (ddp) for large receive of an scsi
i/o coming into fc_fcp, we call into libfc_function_template's ddp_setup()
to prepare for a ddp of large receive for this read I/O. When I/O is complete,
we call the corresponding ddp_done() to get the length of data ddped as well
as to let LLD do clean up.
fc_fcp_ddp_setup()/fc_fcp_ddp_done() are added to setup and complete a ddped
read I/O described by the given fc_fcp_pkt. They would call into corresponding
ddp_setup/ddp_done implemented by the fcoe layer. Eventually, fcoe layer calls
into LLD's ddp_setup/ddp_done provided through net_device
Signed-off-by: Yi Zou <yi.zou@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
index 8a0c5c2..992af05 100644
--- a/drivers/scsi/libfc/fc_exch.c
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -489,7 +489,7 @@
struct fc_exch *ep = NULL;
if (mp->max_read) {
- if (fc_frame_is_read(fp)) {
+ if (fc_fcp_is_read(fr_fsp(fp))) {
min = mp->min_xid;
max = mp->max_read;
plast = &mp->last_read;
@@ -1841,6 +1841,8 @@
fc_exch_setup_hdr(ep, fp, ep->f_ctl);
sp->cnt++;
+ fc_fcp_ddp_setup(fr_fsp(fp), ep->xid);
+
if (unlikely(lp->tt.frame_send(lp, fp)))
goto err;
diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c
index 48adb89..a5725f3 100644
--- a/drivers/scsi/libfc/fc_fcp.c
+++ b/drivers/scsi/libfc/fc_fcp.c
@@ -265,6 +265,56 @@
}
/*
+ * fc_fcp_ddp_setup - calls to LLD's ddp_setup to set up DDP
+ * transfer for a read I/O indicated by the fc_fcp_pkt.
+ * @fsp: ptr to the fc_fcp_pkt
+ *
+ * This is called in exch_seq_send() when we have a newly allocated
+ * exchange with a valid exchange id to setup ddp.
+ *
+ * returns: none
+ */
+void fc_fcp_ddp_setup(struct fc_fcp_pkt *fsp, u16 xid)
+{
+ struct fc_lport *lp;
+
+ if (!fsp)
+ return;
+
+ lp = fsp->lp;
+ if ((fsp->req_flags & FC_SRB_READ) &&
+ (lp->lro_enabled) && (lp->tt.ddp_setup)) {
+ if (lp->tt.ddp_setup(lp, xid, scsi_sglist(fsp->cmd),
+ scsi_sg_count(fsp->cmd)))
+ fsp->xfer_ddp = xid;
+ }
+}
+EXPORT_SYMBOL(fc_fcp_ddp_setup);
+
+/*
+ * fc_fcp_ddp_done - calls to LLD's ddp_done to release any
+ * DDP related resources for this I/O if it is initialized
+ * as a ddp transfer
+ * @fsp: ptr to the fc_fcp_pkt
+ *
+ * returns: none
+ */
+static void fc_fcp_ddp_done(struct fc_fcp_pkt *fsp)
+{
+ struct fc_lport *lp;
+
+ if (!fsp)
+ return;
+
+ lp = fsp->lp;
+ if (fsp->xfer_ddp && lp->tt.ddp_done) {
+ fsp->xfer_len = lp->tt.ddp_done(lp, fsp->xfer_ddp);
+ fsp->xfer_ddp = 0;
+ }
+}
+
+
+/*
* Receive SCSI data from target.
* Called after receiving solicited data.
*/
@@ -289,6 +339,9 @@
len = fr_len(fp) - sizeof(*fh);
buf = fc_frame_payload_get(fp, 0);
+ /* if this I/O is ddped, update xfer len */
+ fc_fcp_ddp_done(fsp);
+
if (offset + len > fsp->data_len) {
/* this should never happen */
if ((fr_flags(fp) & FCPHF_CRC_UNCHECKED) &&
@@ -750,6 +803,9 @@
fsp->scsi_comp_flags = flags;
expected_len = fsp->data_len;
+ /* if ddp, update xfer len */
+ fc_fcp_ddp_done(fsp);
+
if (unlikely((flags & ~FCP_CONF_REQ) || fc_rp->fr_status)) {
rp_ex = (void *)(fc_rp + 1);
if (flags & (FCP_RSP_LEN_VAL | FCP_SNS_LEN_VAL)) {
@@ -1012,7 +1068,7 @@
}
memcpy(fc_frame_payload_get(fp, len), &fsp->cdb_cmd, len);
- fr_cmd(fp) = fsp->cmd;
+ fr_fsp(fp) = fsp;
rport = fsp->rport;
fsp->max_payload = rport->maxframe_size;
rp = rport->dd_data;
@@ -1746,6 +1802,9 @@
struct fc_lport *lp;
unsigned long flags;
+ /* release outstanding ddp context */
+ fc_fcp_ddp_done(fsp);
+
fsp->state |= FC_SRB_COMPL;
if (!(fsp->state & FC_SRB_FCP_PROCESSING_TMO)) {
spin_unlock_bh(&fsp->scsi_pkt_lock);