[PATCH 09/11] libfc: add support of large receive offload by ddp in fc_fcp

Yi Zou
2009-02-27T22:07:21Z

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>
---

drivers/scsi/libfc/fc_exch.c | 4 ++-
drivers/scsi/libfc/fc_fcp.c | 61 +++++++++++++++++++++++++++++++++++++++++-
include/scsi/fc_frame.h | 19 +------------
include/scsi/libfc.h | 30 +++++++++++++++++++++
include/scsi/libfcoe.h | 18 ------------
5 files changed, 95 insertions(+), 37 deletions(-)

diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
index 505825b..d9d01e7 100644
--- a/drivers/scsi/libfc/fc_exch.c
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -489,7 +489,7 @@ static u16 fc_em_alloc_xid(struct fc_exch_mgr *mp, const struct fc_frame *fp)
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 @@ struct fc_seq *fc_exch_seq_send(struct fc_lport *lp,
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 80e8491..379d299 100644
--- a/drivers/scsi/libfc/fc_fcp.c
+++ b/drivers/scsi/libfc/fc_fcp.c
@@ -265,6 +265,56 @@ static void fc_fcp_retry_cmd(struct fc_fcp_pkt *fsp)
}

/*
+ * 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 @@ static void fc_fcp_recv_data(struct fc_fcp_pkt *fsp, struct fc_frame *fp)
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 @@ static void fc_fcp_resp(struct fc_fcp_pkt *fsp, struct fc_frame *fp)
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 @@ static int fc_fcp_cmd_send(struct fc_lport *lp, struct fc_fcp_pkt *fsp,
}

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 @@ static void fc_io_compl(struct fc_fcp_pkt *fsp)
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);
diff --git a/include/scsi/fc_frame.h b/include/scsi/fc_frame.h
index 04d34a7..5951105 100644
--- a/include/scsi/fc_frame.h
+++ b/include/scsi/fc_frame.h
@@ -54,8 +54,7 @@
#define fr_eof(fp) (fr_cb(fp)->fr_eof)
#define fr_flags(fp) (fr_cb(fp)->fr_flags)
#define fr_max_payload(fp) (fr_cb(fp)->fr_max_payload)
-#define fr_cmd(fp) (fr_cb(fp)->fr_cmd)
-#define fr_dir(fp) (fr_cmd(fp)->sc_data_direction)
+#define fr_fsp(fp) (fr_cb(fp)->fr_fsp)
#define fr_crc(fp) (fr_cb(fp)->fr_crc)

struct fc_frame {
@@ -66,7 +65,7 @@ struct fcoe_rcv_info {
struct packet_type *ptype;
struct fc_lport *fr_dev; /* transport layer private pointer */
struct fc_seq *fr_seq; /* for use with exchange manager */
- struct scsi_cmnd *fr_cmd; /* for use of scsi command */
+ struct fc_fcp_pkt *fr_fsp; /* for the corresponding fcp I/O */
u32 fr_crc;
u16 fr_max_payload; /* max FC payload */
enum fc_sof fr_sof; /* start of frame delimiter */
@@ -218,20 +217,6 @@ static inline bool fc_frame_is_cmd(const struct fc_frame *fp)
return fc_frame_rctl(fp) == FC_RCTL_DD_UNSOL_CMD;
}

-static inline bool fc_frame_is_read(const struct fc_frame *fp)
-{
- if (fc_frame_is_cmd(fp) && fr_cmd(fp))
- return fr_dir(fp) == DMA_FROM_DEVICE;
- return false;
-}
-
-static inline bool fc_frame_is_write(const struct fc_frame *fp)
-{
- if (fc_frame_is_cmd(fp) && fr_cmd(fp))
- return fr_dir(fp) == DMA_TO_DEVICE;
- return false;
-}
-
/*
* Check for leaks.
* Print the frame header of any currently allocated frame, assuming there
diff --git a/include/scsi/libfc.h b/include/scsi/libfc.h
index 61c746c..a70eafa 100644
--- a/include/scsi/libfc.h
+++ b/include/scsi/libfc.h
@@ -245,6 +245,7 @@ struct fc_fcp_pkt {
*/
struct fcp_cmnd cdb_cmd;
size_t xfer_len;
+ u16 xfer_ddp; /* this xfer is ddped */
u32 xfer_contig_end; /* offset of end of contiguous xfer */
u16 max_payload; /* max payload size in bytes */

@@ -267,6 +268,15 @@ struct fc_fcp_pkt {
u8 recov_retry; /* count of recovery retries */
struct fc_seq *recov_seq; /* sequence for REC or SRR */
};
+/*
+ * FC_FCP HELPER FUNCTIONS
+ *****************************/
+static inline bool fc_fcp_is_read(const struct fc_fcp_pkt *fsp)
+{
+ if (fsp && fsp->cmd)
+ return fsp->cmd->sc_data_direction == DMA_FROM_DEVICE;
+ return false;
+}

/*
* Structure and function definitions for managing Fibre Channel Exchanges
@@ -400,6 +410,21 @@ struct libfc_function_template {
void *arg, unsigned int timer_msec);

/*
+ * Sets up the DDP context for a given exchange id on the given
+ * scatterlist if LLD supports DDP for large receive.
+ *
+ * STATUS: OPTIONAL
+ */
+ int (*ddp_setup)(struct fc_lport *lp, u16 xid,
+ struct scatterlist *sgl, unsigned int sgc);
+ /*
+ * Completes the DDP transfer and returns the length of data DDPed
+ * for the given exchange id.
+ *
+ * STATUS: OPTIONAL
+ */
+ int (*ddp_done)(struct fc_lport *lp, u16 xid);
+ /*
* Send a frame using an existing sequence and exchange.
*
* STATUS: OPTIONAL
@@ -822,6 +847,11 @@ int fc_change_queue_type(struct scsi_device *sdev, int tag_type);
void fc_fcp_destroy(struct fc_lport *);

/*
+ * Set up direct-data placement for this I/O request
+ */
+void fc_fcp_ddp_setup(struct fc_fcp_pkt *fsp, u16 xid);
+
+/*
* ELS/CT interface
*****************************/
/*
diff --git a/include/scsi/libfcoe.h b/include/scsi/libfcoe.h
index 941818f..c41f7d0 100644
--- a/include/scsi/libfcoe.h
+++ b/include/scsi/libfcoe.h
@@ -124,24 +124,6 @@ static inline u16 skb_fc_rxid(const struct sk_buff *skb)
return be16_to_cpu(skb_fc_header(skb)->fh_rx_id);
}

-/* FIXME - DMA_BIDIRECTIONAL ? */
-#define skb_cb(skb) ((struct fcoe_rcv_info *)&((skb)->cb[0]))
-#define skb_cmd(skb) (skb_cb(skb)->fr_cmd)
-#define skb_dir(skb) (skb_cmd(skb)->sc_data_direction)
-static inline bool skb_fc_is_read(const struct sk_buff *skb)
-{
- if (skb_fc_is_cmd(skb) && skb_cmd(skb))
- return skb_dir(skb) == DMA_FROM_DEVICE;
- return false;
-}
-
-static inline bool skb_fc_is_write(const struct sk_buff *skb)
-{
- if (skb_fc_is_cmd(skb) && skb_cmd(skb))
- return skb_dir(skb) == DMA_TO_DEVICE;
- return false;
-}
-
/* libfcoe funcs */
int fcoe_reset(struct Scsi_Host *shost);
u64 fcoe_wwn_from_mac(unsigned char mac[MAX_ADDR_LEN],