libceph: small write_partial_msg_pages() refactor

Define local variables page_offset and length to represent the range
of bytes within a page that will be sent by ceph_tcp_sendpage() in
write_partial_msg_pages().

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

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index e8fa4497f42430f17734cca7a757e3ab40e8213c..813c29924d5621d806995918ad7494bd17b58805 100644 (file)
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -1081,7 +1081,6 @@ static int write_partial_msg_pages(struct ceph_connection *con)
        struct ceph_msg *msg = con->out_msg;
        struct ceph_msg_pos *msg_pos = &con->out_msg_pos;
        unsigned int data_len = le32_to_cpu(msg->hdr.data_len);
-       size_t len;
        bool do_datacrc = !con->msgr->nocrc;
        int ret;
        int total_max_write;
@@ -1102,6 +1101,8 @@ static int write_partial_msg_pages(struct ceph_connection *con)
         */
        while (data_len > msg_pos->data_pos) {
                struct page *page = NULL;
+               size_t page_offset;
+               size_t length;
                int max_write = PAGE_SIZE;
                int bio_offset = 0;
 
@@ -1131,9 +1132,10 @@ static int write_partial_msg_pages(struct ceph_connection *con)
                } else {
                        page = zero_page;
                }
-               len = min_t(int, max_write - msg_pos->page_pos,
+               length = min_t(int, max_write - msg_pos->page_pos,
                            total_max_write);
 
+               page_offset = msg_pos->page_pos + bio_offset;
                if (do_datacrc && !msg_pos->did_page_crc) {
                        void *base;
                        u32 crc = le32_to_cpu(msg->footer.data_crc);
@@ -1141,19 +1143,18 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 
                        kaddr = kmap(page);
                        BUG_ON(kaddr == NULL);
-                       base = kaddr + msg_pos->page_pos + bio_offset;
-                       crc = crc32c(crc, base, len);
+                       base = kaddr + page_offset;
+                       crc = crc32c(crc, base, length);
                        kunmap(page);
                        msg->footer.data_crc = cpu_to_le32(crc);
                        msg_pos->did_page_crc = true;
                }
-               ret = ceph_tcp_sendpage(con->sock, page,
-                                     msg_pos->page_pos + bio_offset,
-                                     len, true);
+               ret = ceph_tcp_sendpage(con->sock, page, page_offset,
+                                     length, true);
                if (ret <= 0)
                        goto out;
 
-               out_msg_pos_next(con, page, len, (size_t) ret, in_trail);
+               out_msg_pos_next(con, page, length, (size_t) ret, in_trail);
        }
 
        dout("write_partial_msg_pages %p msg %p done\n", con, msg);