[SCSI] iscsi: convert xmit path to iscsi chunks

Convert xmit to iscsi chunks.

from michaelc@cs.wisc.edu:

Bug fixes, more digest integration, sg chaining conversion and other
sg wrapper changes, coding style sync up, and removal of io fields,
like pdu_sent, that are not needed.
Signed-off-by: Olaf Kirch <olaf.kirch@oracle.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/infiniband/ulp/iser/iscsi_iser.c

@@ -129,7 +129,7 @@ iscsi_iser_recv(struct iscsi_conn *conn,
  * iscsi_iser_cmd_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
  *
  **/
-static void
+static int
 iscsi_iser_cmd_init(struct iscsi_cmd_task *ctask)
 {
 	struct iscsi_iser_conn     *iser_conn  = ctask->conn->dd_data;
@@ -138,6 +138,7 @@ iscsi_iser_cmd_init(struct iscsi_cmd_task *ctask)
 	iser_ctask->command_sent = 0;
 	iser_ctask->iser_conn    = iser_conn;
 	iser_ctask_rdma_init(iser_ctask);
+	return 0;
 }
 
 /**

drivers/scsi/iscsi_tcp.h

@@ -24,35 +24,18 @@
 
 #include <scsi/libiscsi.h>
 
-/* xmit state machine */
-#define XMSTATE_IDLE			0x0
-#define XMSTATE_CMD_HDR_INIT		0x1
-#define XMSTATE_CMD_HDR_XMIT		0x2
-#define XMSTATE_IMM_HDR			0x4
-#define XMSTATE_IMM_DATA		0x8
-#define XMSTATE_UNS_INIT		0x10
-#define XMSTATE_UNS_HDR			0x20
-#define XMSTATE_UNS_DATA		0x40
-#define XMSTATE_SOL_HDR			0x80
-#define XMSTATE_SOL_DATA		0x100
-#define XMSTATE_W_PAD			0x200
-#define XMSTATE_W_RESEND_PAD		0x400
-#define XMSTATE_W_RESEND_DATA_DIGEST	0x800
-#define XMSTATE_IMM_HDR_INIT		0x1000
-#define XMSTATE_SOL_HDR_INIT		0x2000
-
 #define ISCSI_SG_TABLESIZE		SG_ALL
 #define ISCSI_TCP_MAX_CMD_LEN		16
 
 struct crypto_hash;
 struct socket;
 struct iscsi_tcp_conn;
-struct iscsi_chunk;
+struct iscsi_segment;
 
-typedef int iscsi_chunk_done_fn_t(struct iscsi_tcp_conn *,
-				  struct iscsi_chunk *);
+typedef int iscsi_segment_done_fn_t(struct iscsi_tcp_conn *,
+				    struct iscsi_segment *);
 
-struct iscsi_chunk {
+struct iscsi_segment {
 	unsigned char		*data;
 	unsigned int		size;
 	unsigned int		copied;
@@ -67,16 +50,14 @@ struct iscsi_chunk {
 	struct scatterlist	*sg;
 	void			*sg_mapped;
 	unsigned int		sg_offset;
-	unsigned int		sg_index;
-	unsigned int		sg_count;
 
-	iscsi_chunk_done_fn_t	*done;
+	iscsi_segment_done_fn_t	*done;
 };
 
 /* Socket connection recieve helper */
 struct iscsi_tcp_recv {
 	struct iscsi_hdr	*hdr;
-	struct iscsi_chunk	chunk;
+	struct iscsi_segment	segment;
 
 	/* Allocate buffer for BHS + AHS */
 	uint32_t		hdr_buf[64];
@@ -88,11 +69,8 @@ struct iscsi_tcp_recv {
 /* Socket connection send helper */
 struct iscsi_tcp_send {
 	struct iscsi_hdr	*hdr;
-	struct iscsi_chunk	chunk;
-	struct iscsi_chunk	data_chunk;
-
-	/* Allocate buffer for BHS + AHS */
-	uint32_t		hdr_buf[64];
+	struct iscsi_segment	segment;
+	struct iscsi_segment	data_segment;
 };
 
 struct iscsi_tcp_conn {
@@ -118,29 +96,19 @@ struct iscsi_tcp_conn {
 	uint32_t		sendpage_failures_cnt;
 	uint32_t		discontiguous_hdr_cnt;
 
-	ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);
-};
+	int			error;
 
-struct iscsi_buf {
-	struct scatterlist	sg;
-	unsigned int		sent;
-	char			use_sendmsg;
+	ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);
 };
 
 struct iscsi_data_task {
 	struct iscsi_data	hdr;			/* PDU */
 	char			hdrext[ISCSI_DIGEST_SIZE];/* Header-Digest */
-	struct iscsi_buf	digestbuf;		/* digest buffer */
-	uint32_t		digest;			/* data digest */
 };
 
 struct iscsi_tcp_mgmt_task {
 	struct iscsi_hdr	hdr;
 	char			hdrext[ISCSI_DIGEST_SIZE]; /* Header-Digest */
-	int			xmstate;	/* mgmt xmit progress */
-	struct iscsi_buf	headbuf;	/* header buffer */
-	struct iscsi_buf	sendbuf;	/* in progress buffer */
-	int			sent;
 };
 
 struct iscsi_r2t_info {
@@ -148,13 +116,10 @@ struct iscsi_r2t_info {
 	__be32			exp_statsn;	/* copied from R2T */
 	uint32_t		data_length;	/* copied from R2T */
 	uint32_t		data_offset;	/* copied from R2T */
-	struct iscsi_buf	headbuf;	/* Data-Out Header Buffer */
-	struct iscsi_buf	sendbuf;	/* Data-Out in progress buffer*/
 	int			sent;		/* R2T sequence progress */
 	int			data_count;	/* DATA-Out payload progress */
-	struct scatterlist	*sg;		/* per-R2T SG list */
 	int			solicit_datasn;
-	struct iscsi_data_task   dtask;        /* which data task */
+	struct iscsi_data_task	dtask;		/* Data-Out header buf */
 };
 
 struct iscsi_tcp_cmd_task {
@@ -163,24 +128,14 @@ struct iscsi_tcp_cmd_task {
 		char			hdrextbuf[ISCSI_MAX_AHS_SIZE +
 		                                  ISCSI_DIGEST_SIZE];
 	} hdr;
-	char			pad[ISCSI_PAD_LEN];
-	int			pad_count;		/* padded bytes */
-	struct iscsi_buf	headbuf;		/* header buf (xmit) */
-	struct iscsi_buf	sendbuf;		/* in progress buffer*/
-	int			xmstate;		/* xmit xtate machine */
+
 	int			sent;
-	struct scatterlist	*sg;			/* per-cmd SG list  */
-	struct scatterlist	*bad_sg;		/* assert statement */
-	int			sg_count;		/* SG's to process  */
 	uint32_t		exp_datasn;	/* expected target's R2TSN/DataSN */
 	int			data_offset;
 	struct iscsi_r2t_info	*r2t;		/* in progress R2T    */
 	struct iscsi_pool	r2tpool;
 	struct kfifo		*r2tqueue;
-	int			digest_count;
-	uint32_t		immdigest;		/* for imm data */
-	struct iscsi_buf	immbuf;			/* for imm data digest */
-	struct iscsi_data_task	unsol_dtask;	/* unsol data task */
+	struct iscsi_data_task	unsol_dtask;	/* Data-Out header buf */
 };
 
 #endif /* ISCSI_H */

drivers/scsi/libiscsi.c

@@ -169,7 +169,6 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 		memset(&hdr->cdb[sc->cmd_len], 0,
 			MAX_COMMAND_SIZE - sc->cmd_len);
 
-	ctask->data_count = 0;
 	ctask->imm_count = 0;
 	if (sc->sc_data_direction == DMA_TO_DEVICE) {
 		hdr->flags |= ISCSI_FLAG_CMD_WRITE;
@@ -198,9 +197,9 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 			else
 				ctask->imm_count = min(scsi_bufflen(sc),
 							conn->max_xmit_dlength);
-			hton24(ctask->hdr->dlength, ctask->imm_count);
+			hton24(hdr->dlength, ctask->imm_count);
 		} else
-			zero_data(ctask->hdr->dlength);
+			zero_data(hdr->dlength);
 
 		if (!session->initial_r2t_en) {
 			ctask->unsol_count = min((session->first_burst),
@@ -210,7 +209,7 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 
 		if (!ctask->unsol_count)
 			/* No unsolicit Data-Out's */
-			ctask->hdr->flags |= ISCSI_FLAG_CMD_FINAL;
+			hdr->flags |= ISCSI_FLAG_CMD_FINAL;
 	} else {
 		hdr->flags |= ISCSI_FLAG_CMD_FINAL;
 		zero_data(hdr->dlength);
@@ -228,8 +227,10 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 	WARN_ON(hdrlength >= 256);
 	hdr->hlength = hdrlength & 0xFF;
 
-	conn->scsicmd_pdus_cnt++;
+	if (conn->session->tt->init_cmd_task(conn->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",
@@ -927,7 +928,7 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
 			fail_command(conn, conn->ctask, DID_ABORT << 16);
 			continue;
 		}
-		conn->session->tt->init_cmd_task(conn->ctask);
+
 		conn->ctask->state = ISCSI_TASK_RUNNING;
 		list_move_tail(conn->xmitqueue.next, &conn->run_list);
 		rc = iscsi_xmit_ctask(conn);

include/scsi/scsi_transport_iscsi.h

@@ -118,7 +118,7 @@ struct iscsi_transport {
 			 char *data, uint32_t data_size);
 	void (*get_stats) (struct iscsi_cls_conn *conn,
 			   struct iscsi_stats *stats);
-	void (*init_cmd_task) (struct iscsi_cmd_task *ctask);
+	int (*init_cmd_task) (struct iscsi_cmd_task *ctask);
 	void (*init_mgmt_task) (struct iscsi_conn *conn,
 				struct iscsi_mgmt_task *mtask);
 	int (*xmit_cmd_task) (struct iscsi_conn *conn,