libceph: more cleanup of write_partial_msg_pages()

Basically all cases in write_partial_msg_pages() use the cursor, and
as a result we can simplify that function quite a bit.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

1 files changed, 7 insertions, 14 deletions

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index ff58d3182754..997daccf973a 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -1476,7 +1476,6 @@ static int write_partial_message_data(struct ceph_connection *con)
         unsigned int data_len = le32_to_cpu(msg->hdr.data_len);
         bool do_datacrc = !con->msgr->nocrc;
         int ret;
-        int total_max_write;
 
         dout("%s %p msg %p page %d offset %d\n", __func__,
              con, msg, msg_pos->page, msg_pos->page_pos);
@@ -1490,36 +1489,30 @@ static int write_partial_message_data(struct ceph_connection *con)
          * been revoked, so use the zero page.
          */
         while (data_len > msg_pos->data_pos) {
-                struct page *page = NULL;
+                struct page *page;
                 size_t page_offset;
                 size_t length;
-                bool use_cursor = false;
-                bool last_piece = true; /* preserve existing behavior */
-
-                total_max_write = data_len - msg_pos->data_pos;
+                bool last_piece;
 
                 if (ceph_msg_has_pages(msg)) {
-                        use_cursor = true;
                         page = ceph_msg_data_next(&msg->p, &page_offset,
                                                         &length, &last_piece);
                 } else if (ceph_msg_has_pagelist(msg)) {
-                        use_cursor = true;
                         page = ceph_msg_data_next(&msg->l, &page_offset,
                                                         &length, &last_piece);
 #ifdef CONFIG_BLOCK
                 } else if (ceph_msg_has_bio(msg)) {
-                        use_cursor = true;
                         page = ceph_msg_data_next(&msg->b, &page_offset,
                                                         &length, &last_piece);
 #endif
                 } else {
-                        page = zero_page;
-                }
-                if (!use_cursor) {
-                        length = min_t(int, PAGE_SIZE - msg_pos->page_pos,
-                                            total_max_write);
+                        size_t resid = data_len - msg_pos->data_pos;
 
+                        page = zero_page;
                         page_offset = msg_pos->page_pos;
+                        length = PAGE_SIZE - page_offset;
+                        length = min(resid, length);
+                        last_piece = length == resid;
                 }
                 if (do_datacrc && !msg_pos->did_page_crc) {
                         u32 crc = le32_to_cpu(msg->footer.data_crc);