libceph: define ceph_msg_has_*() data macros

Define and use macros ceph_msg_has_*() to determine whether to
operate on the pages, pagelist, bio, and trail fields of a message.

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

diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index 1991a6f..889fe47 100644 (file)
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -64,6 +64,13 @@ struct ceph_messenger {
        u32 required_features;
 };
 
+#define ceph_msg_has_pages(m)          ((m)->pages != NULL)
+#define ceph_msg_has_pagelist(m)       ((m)->pagelist != NULL)
+#ifdef CONFIG_BLOCK
+#define ceph_msg_has_bio(m)            ((m)->bio != NULL)
+#endif /* CONFIG_BLOCK */
+#define ceph_msg_has_trail(m)          ((m)->trail != NULL)
+
 /*
  * a single message.  it contains a header (src, dest, message type, etc.),
  * footer (crc values, mainly), a "front" message body, and possibly a

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index f70bc92..c74b528 100644 (file)
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -746,12 +746,12 @@ static void prepare_message_data(struct ceph_msg *msg,
 
        /* initialize page iterator */
        msg_pos->page = 0;
-       if (msg->pages)
+       if (ceph_msg_has_pages(msg))
                msg_pos->page_pos = msg->page_alignment;
        else
                msg_pos->page_pos = 0;
 #ifdef CONFIG_BLOCK
-       if (msg->bio)
+       if (ceph_msg_has_bio(msg))
                init_bio_iter(msg->bio, &msg->bio_iter, &msg->bio_seg);
 #endif
        msg_pos->data_pos = 0;
@@ -1052,14 +1052,16 @@ static void out_msg_pos_next(struct ceph_connection *con, struct page *page,
        msg_pos->page_pos = 0;
        msg_pos->page++;
        msg_pos->did_page_crc = false;
-       if (in_trail)
+       if (in_trail) {
+               BUG_ON(!ceph_msg_has_trail(msg));
                list_rotate_left(&msg->trail->head);
-       else if (msg->pagelist)
+       } else if (ceph_msg_has_pagelist(msg)) {
                list_rotate_left(&msg->pagelist->head);
 #ifdef CONFIG_BLOCK
-       else if (msg->bio)
+       } else if (ceph_msg_has_bio(msg)) {
                iter_bio_next(&msg->bio_iter, &msg->bio_seg);
 #endif
+       }
 }
 
 static void in_msg_pos_next(struct ceph_connection *con, size_t len,
@@ -1114,8 +1116,13 @@ static int write_partial_message_data(struct ceph_connection *con)
        int ret;
        int total_max_write;
        bool in_trail = false;
-       const size_t trail_len = (msg->trail ? msg->trail->length : 0);
-       const size_t trail_off = data_len - trail_len;
+       size_t trail_len = 0;
+       size_t trail_off = data_len;
+
+       if (ceph_msg_has_trail(msg)) {
+               trail_len = msg->trail->length;
+               trail_off -= trail_len;
+       }
 
        dout("%s %p msg %p page %d offset %d\n", __func__,
             con, msg, msg_pos->page, msg_pos->page_pos);
@@ -1140,17 +1147,17 @@ static int write_partial_message_data(struct ceph_connection *con)
                        total_max_write = trail_off - msg_pos->data_pos;
 
                if (in_trail) {
+                       BUG_ON(!ceph_msg_has_trail(msg));
                        total_max_write = data_len - msg_pos->data_pos;
-
                        page = list_first_entry(&msg->trail->head,
                                                struct page, lru);
-               } else if (msg->pages) {
+               } else if (ceph_msg_has_pages(msg)) {
                        page = msg->pages[msg_pos->page];
-               } else if (msg->pagelist) {
+               } else if (ceph_msg_has_pagelist(msg)) {
                        page = list_first_entry(&msg->pagelist->head,
                                                struct page, lru);
 #ifdef CONFIG_BLOCK
-               } else if (msg->bio) {
+               } else if (ceph_msg_has_bio(msg)) {
                        struct bio_vec *bv;
 
                        bv = bio_iovec_idx(msg->bio_iter, msg->bio_seg);
@@ -1908,13 +1915,13 @@ static int read_partial_msg_data(struct ceph_connection *con)
 
        data_len = le32_to_cpu(con->in_hdr.data_len);
        while (msg_pos->data_pos < data_len) {
-               if (msg->pages) {
+               if (ceph_msg_has_pages(msg)) {
                        ret = read_partial_message_pages(con, msg->pages,
                                                 data_len, do_datacrc);
                        if (ret <= 0)
                                return ret;
 #ifdef CONFIG_BLOCK
-               } else if (msg->bio) {
+               } else if (ceph_msg_has_bio(msg)) {
                        ret = read_partial_message_bio(con,
                                                 data_len, do_datacrc);
                        if (ret <= 0)
@@ -2946,16 +2953,19 @@ void ceph_msg_last_put(struct kref *kref)
                ceph_buffer_put(m->middle);
                m->middle = NULL;
        }
-       m->length = 0;
-       m->pages = NULL;
+       if (ceph_msg_has_pages(m)) {
+               m->length = 0;
+               m->pages = NULL;
+       }
 
-       if (m->pagelist) {
+       if (ceph_msg_has_pagelist(m)) {
                ceph_pagelist_release(m->pagelist);
                kfree(m->pagelist);
                m->pagelist = NULL;
        }
 
-       m->trail = NULL;
+       if (ceph_msg_has_trail(m))
+               m->trail = NULL;
 
        if (m->pool)
                ceph_msgpool_put(m->pool, m);