Use sendmsg() with MSG_SPLICE_PAGES rather than sendpage.  This allows
multiple pages and multipage folios to be passed through.

TODO: iscsit_fe_sendpage_sg() should perhaps set up a bio_vec array for the
entire set of pages it's going to transfer plus two for the header and
trailer and page fragments to hold the header and trailer - and then call
sendmsg once for the entire message.

Signed-off-by: David Howells <[email protected]>
cc: Lee Duncan <[email protected]>
cc: Chris Leech <[email protected]>
cc: Mike Christie <[email protected]>
cc: Maurizio Lombardi <[email protected]>
cc: "James E.J. Bottomley" <[email protected]>
cc: "Martin K. Petersen" <[email protected]>
cc: "David S. Miller" <[email protected]>
cc: Eric Dumazet <[email protected]>
cc: Jakub Kicinski <[email protected]>
cc: Paolo Abeni <[email protected]>
cc: Jens Axboe <[email protected]>
cc: Matthew Wilcox <[email protected]>
cc: Al Viro <[email protected]>
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
---

Notes:
    ver #2)
     - Wrap lines at 80.

 drivers/scsi/iscsi_tcp.c                 | 26 +++++++++---------------
 drivers/scsi/iscsi_tcp.h                 |  2 --
 drivers/target/iscsi/iscsi_target_util.c | 15 ++++++++------
 3 files changed, 19 insertions(+), 24 deletions(-)

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 9637d4bc2bc9..9ab8555180a3 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -301,35 +301,32 @@ static int iscsi_sw_tcp_xmit_segment(struct 
iscsi_tcp_conn *tcp_conn,
 
        while (!iscsi_tcp_segment_done(tcp_conn, segment, 0, r)) {
                struct scatterlist *sg;
+               struct msghdr msg = {};
+               struct bio_vec bv;
                unsigned int offset, copy;
-               int flags = 0;
 
                r = 0;
                offset = segment->copied;
                copy = segment->size - offset;
 
                if (segment->total_copied + segment->size < segment->total_size)
-                       flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
+                       msg.msg_flags |= MSG_MORE;
 
                if (tcp_sw_conn->queue_recv)
-                       flags |= MSG_DONTWAIT;
+                       msg.msg_flags |= MSG_DONTWAIT;
 
-               /* Use sendpage if we can; else fall back to sendmsg */
                if (!segment->data) {
+                       if (!tcp_conn->iscsi_conn->datadgst_en)
+                               msg.msg_flags |= MSG_SPLICE_PAGES;
                        sg = segment->sg;
                        offset += segment->sg_offset + sg->offset;
-                       r = tcp_sw_conn->sendpage(sk, sg_page(sg), offset,
-                                                 copy, flags);
+                       bvec_set_page(&bv, sg_page(sg), copy, offset);
                } else {
-                       struct msghdr msg = { .msg_flags = flags };
-                       struct kvec iov = {
-                               .iov_base = segment->data + offset,
-                               .iov_len = copy
-                       };
-
-                       r = kernel_sendmsg(sk, &msg, &iov, 1, copy);
+                       bvec_set_virt(&bv, segment->data + offset, copy);
                }
+               iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bv, 1, copy);
 
+               r = sock_sendmsg(sk, &msg);
                if (r < 0) {
                        iscsi_tcp_segment_unmap(segment);
                        return r;
@@ -746,7 +743,6 @@ iscsi_sw_tcp_conn_bind(struct iscsi_cls_session 
*cls_session,
        sock_no_linger(sk);
 
        iscsi_sw_tcp_conn_set_callbacks(conn);
-       tcp_sw_conn->sendpage = tcp_sw_conn->sock->ops->sendpage;
        /*
         * set receive state machine into initial state
         */
@@ -777,8 +773,6 @@ static int iscsi_sw_tcp_conn_set_param(struct 
iscsi_cls_conn *cls_conn,
                        return -ENOTCONN;
                }
                iscsi_set_param(cls_conn, param, buf, buflen);
-               tcp_sw_conn->sendpage = conn->datadgst_en ?
-                       sock_no_sendpage : tcp_sw_conn->sock->ops->sendpage;
                mutex_unlock(&tcp_sw_conn->sock_lock);
                break;
        case ISCSI_PARAM_MAX_R2T:
diff --git a/drivers/scsi/iscsi_tcp.h b/drivers/scsi/iscsi_tcp.h
index 68e14a344904..89a6fc552f0b 100644
--- a/drivers/scsi/iscsi_tcp.h
+++ b/drivers/scsi/iscsi_tcp.h
@@ -47,8 +47,6 @@ struct iscsi_sw_tcp_conn {
        /* MIB custom statistics */
        uint32_t                sendpage_failures_cnt;
        uint32_t                discontiguous_hdr_cnt;
-
-       ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);
 };
 
 struct iscsi_sw_tcp_host {
diff --git a/drivers/target/iscsi/iscsi_target_util.c 
b/drivers/target/iscsi/iscsi_target_util.c
index b14835fcb033..6231fa4ef5c6 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -1129,6 +1129,8 @@ int iscsit_fe_sendpage_sg(
        struct iscsit_conn *conn)
 {
        struct scatterlist *sg = cmd->first_data_sg;
+       struct bio_vec bvec;
+       struct msghdr msghdr = { .msg_flags = MSG_SPLICE_PAGES, };
        struct kvec iov;
        u32 tx_hdr_size, data_len;
        u32 offset = cmd->first_data_sg_off;
@@ -1172,17 +1174,18 @@ int iscsit_fe_sendpage_sg(
                u32 space = (sg->length - offset);
                u32 sub_len = min_t(u32, data_len, space);
 send_pg:
-               tx_sent = conn->sock->ops->sendpage(conn->sock,
-                                       sg_page(sg), sg->offset + offset, 
sub_len, 0);
+               bvec_set_page(&bvec, sg_page(sg), sub_len, sg->offset + offset);
+               iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, sub_len);
+
+               tx_sent = conn->sock->ops->sendmsg(conn->sock, &msghdr,
+                                                  sub_len);
                if (tx_sent != sub_len) {
                        if (tx_sent == -EAGAIN) {
-                               pr_err("tcp_sendpage() returned"
-                                               " -EAGAIN\n");
+                               pr_err("sendmsg/splice returned -EAGAIN\n");
                                goto send_pg;
                        }
 
-                       pr_err("tcp_sendpage() failure: %d\n",
-                                       tx_sent);
+                       pr_err("sendmsg/splice failure: %d\n", tx_sent);
                        return -1;
                }
 

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