2 files changed, 92 insertions, 33 deletions

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index e11bce6ab63c..464de780d953 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -486,7 +486,8 @@ iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
         struct hash_desc *rx_hash = NULL;
 
-        if (conn->datadgst_en)
+        if (conn->datadgst_en &
+            !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
                 rx_hash = &tcp_conn->rx_hash;
 
         iscsi_segment_init_linear(&tcp_conn->in.segment,
@@ -774,7 +775,8 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
                          * we move on to the next scatterlist entry and
                          * update the digest per-entry.
                          */
-                        if (conn->datadgst_en)
+                        if (conn->datadgst_en &&
+                            !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
                                 rx_hash = &tcp_conn->rx_hash;
 
                         debug_tcp("iscsi_tcp_begin_data_in(%p, offset=%d, "
@@ -902,34 +904,52 @@ iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
          * and go back for more. */
         if (conn->hdrdgst_en) {
                 if (segment->digest_len == 0) {
+                        /*
+                         * Even if we offload the digest processing we
+                         * splice it in so we can increment the skb/segment
+                         * counters in preparation for the data segment.
+                         */
                         iscsi_tcp_segment_splice_digest(segment,
                                                         segment->recv_digest);
                         return 0;
                 }
-                iscsi_tcp_dgst_header(&tcp_conn->rx_hash, hdr,
-                                      segment->total_copied - ISCSI_DIGEST_SIZE,
-                                      segment->digest);
 
-                if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
-                        return ISCSI_ERR_HDR_DGST;
+                if (!(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
+                        iscsi_tcp_dgst_header(&tcp_conn->rx_hash, hdr,
+                                segment->total_copied - ISCSI_DIGEST_SIZE,
+                                segment->digest);
+
+                        if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
+                                return ISCSI_ERR_HDR_DGST;
+                }
         }
 
         tcp_conn->in.hdr = hdr;
         return iscsi_tcp_hdr_dissect(conn, hdr);
 }
 
+inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
+{
+        return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
+}
+
+enum {
+        ISCSI_TCP_SEGMENT_DONE,         /* curr seg has been processed */
+        ISCSI_TCP_SKB_DONE,             /* skb is out of data */
+        ISCSI_TCP_CONN_ERR,             /* iscsi layer has fired a conn err */
+        ISCSI_TCP_SUSPENDED,            /* conn is suspended */
+};
+
 /**
- * iscsi_tcp_recv - TCP receive in sendfile fashion
- * @rd_desc: read descriptor
- * @skb: socket buffer
+ * iscsi_tcp_recv_skb - Process skb
+ * @conn: iscsi connection
+ * @skb: network buffer with header and/or data segment
  * @offset: offset in skb
- * @len: skb->len - offset
- **/
-static int
-iscsi_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
-               unsigned int offset, size_t len)
+ * @offload: bool indicating if transfer was offloaded
+ */
+int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
+                       unsigned int offset, bool offloaded, int *status)
 {
-        struct iscsi_conn *conn = rd_desc->arg.data;
         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
         struct iscsi_segment *segment = &tcp_conn->in.segment;
         struct skb_seq_state seq;
@@ -940,9 +960,15 @@ iscsi_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
 
         if (unlikely(conn->suspend_rx)) {
                 debug_tcp("conn %d Rx suspended!\n", conn->id);
+                *status = ISCSI_TCP_SUSPENDED;
                 return 0;
         }
 
+        if (offloaded) {
+                segment->total_copied = segment->total_size;
+                goto segment_done;
+        }
+
         skb_prepare_seq_read(skb, offset, skb->len, &seq);
         while (1) {
                 unsigned int avail;
@@ -952,7 +978,9 @@ iscsi_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
                 if (avail == 0) {
                         debug_tcp("no more data avail. Consumed %d\n",
                                   consumed);
-                        break;
+                        *status = ISCSI_TCP_SKB_DONE;
+                        skb_abort_seq_read(&seq);
+                        goto skb_done;
                 }
                 BUG_ON(segment->copied >= segment->size);
 
@@ -962,25 +990,55 @@ iscsi_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
                 consumed += rc;
 
                 if (segment->total_copied >= segment->total_size) {
-                        debug_tcp("segment done\n");
-                        rc = segment->done(tcp_conn, segment);
-                        if (rc != 0) {
-                                skb_abort_seq_read(&seq);
-                                goto error;
-                        }
-
-                        /* The done() functions sets up the
-                         * next segment. */
+                        skb_abort_seq_read(&seq);
+                        goto segment_done;
                 }
         }
-        skb_abort_seq_read(&seq);
+
+segment_done:
+        *status = ISCSI_TCP_SEGMENT_DONE;
+        debug_tcp("segment done\n");
+        rc = segment->done(tcp_conn, segment);
+        if (rc != 0) {
+                *status = ISCSI_TCP_CONN_ERR;
+                debug_tcp("Error receiving PDU, errno=%d\n", rc);
+                iscsi_conn_failure(conn, rc);
+                return 0;
+        }
+        /* The done() functions sets up the next segment. */
+
+skb_done:
         conn->rxdata_octets += consumed;
         return consumed;
+}
+EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
 
-error:
-        debug_tcp("Error receiving PDU, errno=%d\n", rc);
-        iscsi_conn_failure(conn, rc);
-        return 0;
+/**
+ * iscsi_tcp_recv - TCP receive in sendfile fashion
+ * @rd_desc: read descriptor
+ * @skb: socket buffer
+ * @offset: offset in skb
+ * @len: skb->len - offset
+ **/
+static int
+iscsi_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
+               unsigned int offset, size_t len)
+{
+        struct iscsi_conn *conn = rd_desc->arg.data;
+        unsigned int consumed, total_consumed = 0;
+        int status;
+
+        debug_tcp("in %d bytes\n", skb->len - offset);
+
+        do {
+                status = 0;
+                consumed = iscsi_tcp_recv_skb(conn, skb, offset, 0, &status);
+                offset += consumed;
+                total_consumed += consumed;
+        } while (consumed != 0 && status != ISCSI_TCP_SKB_DONE);
+
+        debug_tcp("read %d bytes status %d\n", skb->len - offset, status);
+        return total_consumed;
 }
 
 static void
diff --git a/include/scsi/iscsi_if.h b/include/scsi/iscsi_if.h
index 0c9514de5df7..8e008c96e795 100644
--- a/include/scsi/iscsi_if.h
+++ b/include/scsi/iscsi_if.h
@@ -333,8 +333,9 @@ enum iscsi_host_param {
 #define CAP_TEXT_NEGO           0x80
 #define CAP_MARKERS             0x100
 #define CAP_FW_DB               0x200
-#define CAP_SENDTARGETS_OFFLOAD 0x400
-#define CAP_DATA_PATH_OFFLOAD   0x800
+#define CAP_SENDTARGETS_OFFLOAD 0x400   /* offload discovery process */
+#define CAP_DATA_PATH_OFFLOAD   0x800   /* offload entire IO path */
+#define CAP_DIGEST_OFFLOAD      0x1000  /* offload hdr and data digests */
 
 /*
  * These flags describes reason of stop_conn() call