libceph: encapsulate advancing msg page

In write_partial_msg_pages(), once all the data from a page has been
sent we advance to the next one.  Put the code that takes care of
this into its own function.

While modifying write_partial_msg_pages(), make its local variable
"in_trail" be Boolean, and use the local variable "msg" (which is
just the connection's current out_msg pointer) consistently.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

1 files changed, 34 insertions, 24 deletions

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 56448660883d..1b92e3b16c0d 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -891,6 +891,33 @@ static void iter_bio_next(struct bio **bio_iter, int *seg)
 }
 #endif
 
+static void out_msg_pos_next(struct ceph_connection *con, struct page *page,
+                        size_t len, size_t sent, bool in_trail)
+{
+        struct ceph_msg *msg = con->out_msg;
+
+        BUG_ON(!msg);
+        BUG_ON(!sent);
+
+        con->out_msg_pos.data_pos += sent;
+        con->out_msg_pos.page_pos += sent;
+        if (sent == len) {
+                con->out_msg_pos.page_pos = 0;
+                con->out_msg_pos.page++;
+                con->out_msg_pos.did_page_crc = false;
+                if (in_trail)
+                        list_move_tail(&page->lru,
+                                       &msg->trail->head);
+                else if (msg->pagelist)
+                        list_move_tail(&page->lru,
+                                       &msg->pagelist->head);
+#ifdef CONFIG_BLOCK
+                else if (msg->bio)
+                        iter_bio_next(&msg->bio_iter, &msg->bio_seg);
+#endif
+        }
+}
+
 /*
  * Write as much message data payload as we can.  If we finish, queue
  * up the footer.
@@ -906,11 +933,11 @@ static int write_partial_msg_pages(struct ceph_connection *con)
         bool do_datacrc = !con->msgr->nocrc;
         int ret;
         int total_max_write;
-        int in_trail = 0;
+        bool in_trail = false;
         size_t trail_len = (msg->trail ? msg->trail->length : 0);
 
         dout("write_partial_msg_pages %p msg %p page %d/%d offset %d\n",
-             con, con->out_msg, con->out_msg_pos.page, con->out_msg->nr_pages,
+             con, msg, con->out_msg_pos.page, msg->nr_pages,
              con->out_msg_pos.page_pos);
 
 #ifdef CONFIG_BLOCK
@@ -934,13 +961,12 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 
                 /* have we reached the trail part of the data? */
                 if (con->out_msg_pos.data_pos >= data_len - trail_len) {
-                        in_trail = 1;
+                        in_trail = true;
 
                         total_max_write = data_len - con->out_msg_pos.data_pos;
 
                         page = list_first_entry(&msg->trail->head,
                                                 struct page, lru);
-                        max_write = PAGE_SIZE;
                 } else if (msg->pages) {
                         page = msg->pages[con->out_msg_pos.page];
                 } else if (msg->pagelist) {
@@ -964,14 +990,14 @@ static int write_partial_msg_pages(struct ceph_connection *con)
                 if (do_datacrc && !con->out_msg_pos.did_page_crc) {
                         void *base;
                         u32 crc;
-                        u32 tmpcrc = le32_to_cpu(con->out_msg->footer.data_crc);
+                        u32 tmpcrc = le32_to_cpu(msg->footer.data_crc);
                         char *kaddr;
 
                         kaddr = kmap(page);
                         BUG_ON(kaddr == NULL);
                         base = kaddr + con->out_msg_pos.page_pos + bio_offset;
                         crc = crc32c(tmpcrc, base, len);
-                        con->out_msg->footer.data_crc = cpu_to_le32(crc);
+                        msg->footer.data_crc = cpu_to_le32(crc);
                         con->out_msg_pos.did_page_crc = true;
                 }
                 ret = ceph_tcp_sendpage(con->sock, page,
@@ -984,30 +1010,14 @@ static int write_partial_msg_pages(struct ceph_connection *con)
                 if (ret <= 0)
                         goto out;
 
-                con->out_msg_pos.data_pos += ret;
-                con->out_msg_pos.page_pos += ret;
-                if (ret == len) {
-                        con->out_msg_pos.page_pos = 0;
-                        con->out_msg_pos.page++;
-                        con->out_msg_pos.did_page_crc = false;
-                        if (in_trail)
-                                list_move_tail(&page->lru,
-                                               &msg->trail->head);
-                        else if (msg->pagelist)
-                                list_move_tail(&page->lru,
-                                               &msg->pagelist->head);
-#ifdef CONFIG_BLOCK
-                        else if (msg->bio)
-                                iter_bio_next(&msg->bio_iter, &msg->bio_seg);
-#endif
-                }
+                out_msg_pos_next(con, page, len, (size_t) ret, in_trail);
         }
 
         dout("write_partial_msg_pages %p msg %p done\n", con, msg);
 
         /* prepare and queue up footer, too */
         if (!do_datacrc)
-                con->out_msg->footer.flags |= CEPH_MSG_FOOTER_NOCRC;
+                msg->footer.flags |= CEPH_MSG_FOOTER_NOCRC;
         con_out_kvec_reset(con);
         prepare_write_message_footer(con);
         ret = 1;