libceph: combine initializing and setting osd data

This ends up being a rather large patch but what it's doing is
somewhat straightforward.

Basically, this is replacing two calls with one.  The first of the
two calls is initializing a struct ceph_osd_data with data (either a
page array, a page list, or a bio list); the second is setting an
osd request op so it associates that data with one of the op's
parameters.  In place of those two will be a single function that
initializes the op directly.

That means we sort of fan out a set of the needed functions:
    - extent ops with pages data
    - extent ops with pagelist data
    - extent ops with bio list data
and
    - class ops with page data for receiving a response

We also have define another one, but it's only used internally:
    - class ops with pagelist data for request parameters

Note that we *still* haven't gotten rid of the osd request's
r_data_in and r_data_out fields.  All the osd ops refer to them for
their data.  For now, these data fields are pointers assigned to the
appropriate r_data_* field when these new functions are called.

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

5 files changed, 161 insertions, 72 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index db29783436c8..6f7a52cf75c7 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -1592,7 +1592,6 @@ static int rbd_img_request_fill_bio(struct rbd_img_request *img_request,
         rbd_assert(resid > 0);
         while (resid) {
                 struct ceph_osd_request *osd_req;
-                struct ceph_osd_data *osd_data;
                 const char *object_name;
                 unsigned int clone_size;
                 u64 offset;
@@ -1625,13 +1624,10 @@ static int rbd_img_request_fill_bio(struct rbd_img_request *img_request,
                 obj_request->osd_req = osd_req;
                 obj_request->callback = rbd_img_obj_callback;
 
-                osd_data = write_request ? &osd_req->r_data_out
-                                         : &osd_req->r_data_in;
                 osd_req_op_extent_init(osd_req, 0, opcode, offset, length,
                                                 0, 0);
-                ceph_osd_data_bio_init(osd_data, obj_request->bio_list,
-                                        obj_request->length);
-                osd_req_op_extent_osd_data(osd_req, 0, osd_data);
+                osd_req_op_extent_osd_data_bio(osd_req, 0, write_request,
+                                obj_request->bio_list, obj_request->length);
                 rbd_osd_req_format(obj_request, write_request);
 
                 rbd_img_obj_request_add(img_request, obj_request);
@@ -1821,7 +1817,6 @@ static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
 {
         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
         struct rbd_obj_request *obj_request;
-        struct ceph_osd_data *osd_data;
         struct page **pages;
         u32 page_count;
         int ret;
@@ -1851,13 +1846,12 @@ static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
         if (!obj_request->osd_req)
                 goto out;
 
-        osd_data = &obj_request->osd_req->r_data_in;
         osd_req_op_cls_init(obj_request->osd_req, 0, CEPH_OSD_OP_CALL,
                                         class_name, method_name,
                                         outbound, outbound_size);
-        ceph_osd_data_pages_init(osd_data, obj_request->pages, inbound_size,
+        osd_req_op_cls_response_data_pages(obj_request->osd_req, 0,
+                                        obj_request->pages, inbound_size,
                                         0, false, false);
-        osd_req_op_cls_response_data(obj_request->osd_req, 0, osd_data);
         rbd_osd_req_format(obj_request, false);
 
         ret = rbd_obj_request_submit(osdc, obj_request);
@@ -2037,7 +2031,6 @@ static int rbd_obj_read_sync(struct rbd_device *rbd_dev,
 {
         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
         struct rbd_obj_request *obj_request;
-        struct ceph_osd_data *osd_data;
         struct page **pages = NULL;
         u32 page_count;
         size_t size;
@@ -2061,14 +2054,13 @@ static int rbd_obj_read_sync(struct rbd_device *rbd_dev,
         if (!obj_request->osd_req)
                 goto out;
 
-        osd_data = &obj_request->osd_req->r_data_in;
         osd_req_op_extent_init(obj_request->osd_req, 0, CEPH_OSD_OP_READ,
                                         offset, length, 0, 0);
-        ceph_osd_data_pages_init(osd_data, obj_request->pages,
+        osd_req_op_extent_osd_data_pages(obj_request->osd_req, 0, false,
+                                        obj_request->pages,
                                         obj_request->length,
                                         obj_request->offset & ~PAGE_MASK,
                                         false, false);
-        osd_req_op_extent_osd_data(obj_request->osd_req, 0, osd_data);
         rbd_osd_req_format(obj_request, false);
 
         ret = rbd_obj_request_submit(osdc, obj_request);
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index cc57104a7266..27d62070a8e9 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -245,7 +245,7 @@ static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
         dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
 
         /* unlock all pages, zeroing any data we didn't read */
-        osd_data = &req->r_data_in;
+        osd_data = osd_req_op_extent_osd_data(req, 0, false);
         BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
         num_pages = calc_pages_for((u64)osd_data->alignment,
                                         (u64)osd_data->length);
@@ -343,8 +343,7 @@ static int start_read(struct inode *inode, struct list_head *page_list, int max)
                 }
                 pages[i] = page;
         }
-        BUG_ON(req->r_ops[0].extent.osd_data != &req->r_data_in);
-        ceph_osd_data_pages_init(req->r_ops[0].extent.osd_data, pages, len, 0,
+        osd_req_op_extent_osd_data_pages(req, 0, false, pages, len, 0,
                                         false, false);
         req->r_callback = finish_read;
         req->r_inode = inode;
@@ -572,7 +571,7 @@ static void writepages_finish(struct ceph_osd_request *req,
         long writeback_stat;
         unsigned issued = ceph_caps_issued(ci);
 
-        osd_data = &req->r_data_out;
+        osd_data = osd_req_op_extent_osd_data(req, 0, true);
         BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
         num_pages = calc_pages_for((u64)osd_data->alignment,
                                         (u64)osd_data->length);
@@ -917,9 +916,8 @@ get_more_pages:
                 dout("writepages got %d pages at %llu~%llu\n",
                      locked_pages, offset, len);
 
-                BUG_ON(req->r_ops[0].extent.osd_data != &req->r_data_out);
-                ceph_osd_data_pages_init(req->r_ops[0].extent.osd_data, pages,
-                                                len, 0, !!pool, false);
+                osd_req_op_extent_osd_data_pages(req, 0, true, pages, len, 0,
+                                                        !!pool, false);
 
                 pages = NULL;   /* request message now owns the pages array */
                 pool = NULL;
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index cddc10fd7cf9..0f9c4095614b 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -574,8 +574,7 @@ more:
                         own_pages = true;
                 }
         }
-        BUG_ON(req->r_ops[0].extent.osd_data != &req->r_data_out);
-        ceph_osd_data_pages_init(req->r_ops[0].extent.osd_data, pages, len,
+        osd_req_op_extent_osd_data_pages(req, 0, true, pages, len,
                                         page_align, false, own_pages);
 
         /* BUG_ON(vino.snap != CEPH_NOSNAP); */
diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
index 71c41575646d..f8a00b48e550 100644
--- a/include/linux/ceph/osd_client.h
+++ b/include/linux/ceph/osd_client.h
@@ -240,17 +240,39 @@ extern void osd_req_op_extent_init(struct ceph_osd_request *osd_req,
                                         u64 truncate_size, u32 truncate_seq);
 extern void osd_req_op_extent_update(struct ceph_osd_request *osd_req,
                                         unsigned int which, u64 length);
-extern void osd_req_op_extent_osd_data(struct ceph_osd_request *osd_req,
+
+extern struct ceph_osd_data *osd_req_op_extent_osd_data(
+                                        struct ceph_osd_request *osd_req,
+                                        unsigned int which, bool write_request);
+extern struct ceph_osd_data *osd_req_op_cls_response_data(
+                                        struct ceph_osd_request *osd_req,
+                                        unsigned int which);
+
+extern void osd_req_op_extent_osd_data_pages(struct ceph_osd_request *,
+                                        unsigned int which, bool write_request,
+                                        struct page **pages, u64 length,
+                                        u32 alignment, bool pages_from_pool,
+                                        bool own_pages);
+extern void osd_req_op_extent_osd_data_pagelist(struct ceph_osd_request *,
+                                        unsigned int which, bool write_request,
+                                        struct ceph_pagelist *pagelist);
+#ifdef CONFIG_BLOCK
+extern void osd_req_op_extent_osd_data_bio(struct ceph_osd_request *,
+                                        unsigned int which, bool write_request,
+                                        struct bio *bio, size_t bio_length);
+#endif /* CONFIG_BLOCK */
+
+extern void osd_req_op_cls_response_data_pages(struct ceph_osd_request *,
                                         unsigned int which,
-                                        struct ceph_osd_data *osd_data);
+                                        struct page **pages, u64 length,
+                                        u32 alignment, bool pages_from_pool,
+                                        bool own_pages);
+
 extern void osd_req_op_cls_init(struct ceph_osd_request *osd_req,
                                         unsigned int which, u16 opcode,
                                         const char *class, const char *method,
                                         const void *request_data,
                                         size_t request_data_size);
-extern void osd_req_op_cls_response_data(struct ceph_osd_request *osd_req,
-                                        unsigned int which,
-                                        struct ceph_osd_data *response_data);
 extern void osd_req_op_watch_init(struct ceph_osd_request *osd_req,
                                         unsigned int which, u16 opcode,
                                         u64 cookie, u64 version, int flag);
@@ -290,17 +312,6 @@ static inline void ceph_osdc_put_request(struct ceph_osd_request *req)
         kref_put(&req->r_kref, ceph_osdc_release_request);
 }
 
-extern void ceph_osd_data_pages_init(struct ceph_osd_data *osd_data,
-                                     struct page **pages, u64 length,
-                                     u32 alignment, bool pages_from_pool,
-                                     bool own_pages);
-extern void ceph_osd_data_pagelist_init(struct ceph_osd_data *osd_data,
-                                        struct ceph_pagelist *pagelist);
-#ifdef CONFIG_BLOCK
-extern void ceph_osd_data_bio_init(struct ceph_osd_data *osd_data,
-                                   struct bio *bio, size_t bio_length);
-#endif /* CONFIG_BLOCK */
-
 extern int ceph_osdc_start_request(struct ceph_osd_client *osdc,
                                    struct ceph_osd_request *req,
                                    bool nofail);
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 932b8af8b8ee..86cb52404f17 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -1,3 +1,4 @@
+
 #include <linux/ceph/ceph_debug.h>
 
 #include <linux/module.h>
@@ -85,7 +86,7 @@ static void ceph_osd_data_init(struct ceph_osd_data *osd_data)
         osd_data->type = CEPH_OSD_DATA_TYPE_NONE;
 }
 
-void ceph_osd_data_pages_init(struct ceph_osd_data *osd_data,
+static void ceph_osd_data_pages_init(struct ceph_osd_data *osd_data,
                         struct page **pages, u64 length, u32 alignment,
                         bool pages_from_pool, bool own_pages)
 {
@@ -96,27 +97,131 @@ void ceph_osd_data_pages_init(struct ceph_osd_data *osd_data,
         osd_data->pages_from_pool = pages_from_pool;
         osd_data->own_pages = own_pages;
 }
-EXPORT_SYMBOL(ceph_osd_data_pages_init);
 
-void ceph_osd_data_pagelist_init(struct ceph_osd_data *osd_data,
+static void ceph_osd_data_pagelist_init(struct ceph_osd_data *osd_data,
                         struct ceph_pagelist *pagelist)
 {
         osd_data->type = CEPH_OSD_DATA_TYPE_PAGELIST;
         osd_data->pagelist = pagelist;
 }
-EXPORT_SYMBOL(ceph_osd_data_pagelist_init);
 
 #ifdef CONFIG_BLOCK
-void ceph_osd_data_bio_init(struct ceph_osd_data *osd_data,
+static void ceph_osd_data_bio_init(struct ceph_osd_data *osd_data,
                         struct bio *bio, size_t bio_length)
 {
         osd_data->type = CEPH_OSD_DATA_TYPE_BIO;
         osd_data->bio = bio;
         osd_data->bio_length = bio_length;
 }
-EXPORT_SYMBOL(ceph_osd_data_bio_init);
 #endif /* CONFIG_BLOCK */
 
+struct ceph_osd_data *
+osd_req_op_extent_osd_data(struct ceph_osd_request *osd_req,
+                        unsigned int which, bool write_request)
+{
+        BUG_ON(which >= osd_req->r_num_ops);
+
+        /* return &osd_req->r_ops[which].extent.osd_data; */
+        return write_request ? &osd_req->r_data_out : &osd_req->r_data_in;
+}
+EXPORT_SYMBOL(osd_req_op_extent_osd_data);
+
+struct ceph_osd_data *
+osd_req_op_cls_request_info(struct ceph_osd_request *osd_req,
+                        unsigned int which)
+{
+        BUG_ON(which >= osd_req->r_num_ops);
+
+        /* return &osd_req->r_ops[which].cls.request_info; */
+        return &osd_req->r_data_out;    /* Request data is outgoing */
+}
+EXPORT_SYMBOL(osd_req_op_cls_request_info);     /* ??? */
+
+struct ceph_osd_data *
+osd_req_op_cls_response_data(struct ceph_osd_request *osd_req,
+                        unsigned int which)
+{
+        BUG_ON(which >= osd_req->r_num_ops);
+
+        /* return &osd_req->r_ops[which].cls.response_data; */
+        return &osd_req->r_data_in;     /* Response data is incoming */
+}
+EXPORT_SYMBOL(osd_req_op_cls_response_data);    /* ??? */
+
+void osd_req_op_extent_osd_data_pages(struct ceph_osd_request *osd_req,
+                        unsigned int which, bool write_request,
+                        struct page **pages, u64 length, u32 alignment,
+                        bool pages_from_pool, bool own_pages)
+{
+        struct ceph_osd_data *osd_data;
+
+        osd_data = osd_req_op_extent_osd_data(osd_req, which, write_request);
+        ceph_osd_data_pages_init(osd_data, pages, length, alignment,
+                                pages_from_pool, own_pages);
+
+        osd_req->r_ops[which].extent.osd_data =
+                osd_req_op_extent_osd_data(osd_req, which, write_request);
+}
+EXPORT_SYMBOL(osd_req_op_extent_osd_data_pages);
+
+void osd_req_op_extent_osd_data_pagelist(struct ceph_osd_request *osd_req,
+                        unsigned int which, bool write_request,
+                        struct ceph_pagelist *pagelist)
+{
+        struct ceph_osd_data *osd_data;
+
+        osd_data = osd_req_op_extent_osd_data(osd_req, which, write_request);
+        ceph_osd_data_pagelist_init(osd_data, pagelist);
+
+        osd_req->r_ops[which].extent.osd_data =
+                osd_req_op_extent_osd_data(osd_req, which, write_request);
+}
+EXPORT_SYMBOL(osd_req_op_extent_osd_data_pagelist);
+
+#ifdef CONFIG_BLOCK
+void osd_req_op_extent_osd_data_bio(struct ceph_osd_request *osd_req,
+                        unsigned int which, bool write_request,
+                        struct bio *bio, size_t bio_length)
+{
+        struct ceph_osd_data *osd_data;
+
+        osd_data = osd_req_op_extent_osd_data(osd_req, which, write_request);
+        ceph_osd_data_bio_init(osd_data, bio, bio_length);
+
+        osd_req->r_ops[which].extent.osd_data =
+                osd_req_op_extent_osd_data(osd_req, which, write_request);
+}
+EXPORT_SYMBOL(osd_req_op_extent_osd_data_bio);
+#endif /* CONFIG_BLOCK */
+
+static void osd_req_op_cls_request_info_pagelist(
+                        struct ceph_osd_request *osd_req,
+                        unsigned int which, struct ceph_pagelist *pagelist)
+{
+        struct ceph_osd_data *osd_data;
+
+        osd_data = osd_req_op_cls_request_info(osd_req, which);
+        ceph_osd_data_pagelist_init(osd_data, pagelist);
+
+        osd_req->r_ops[which].cls.request_info =
+                osd_req_op_cls_request_info(osd_req, which);
+}
+
+void osd_req_op_cls_response_data_pages(struct ceph_osd_request *osd_req,
+                        unsigned int which, struct page **pages, u64 length,
+                        u32 alignment, bool pages_from_pool, bool own_pages)
+{
+        struct ceph_osd_data *osd_data;
+
+        osd_data = osd_req_op_cls_response_data(osd_req, which);
+        ceph_osd_data_pages_init(osd_data, pages, length, alignment,
+                                pages_from_pool, own_pages);
+
+        osd_req->r_ops[which].cls.response_data =
+                osd_req_op_cls_response_data(osd_req, which);
+}
+EXPORT_SYMBOL(osd_req_op_cls_response_data_pages);
+
 static u64 ceph_osd_data_length(struct ceph_osd_data *osd_data)
 {
         switch (osd_data->type) {
@@ -385,15 +490,6 @@ void osd_req_op_extent_update(struct ceph_osd_request *osd_req,
 }
 EXPORT_SYMBOL(osd_req_op_extent_update);
 
-void osd_req_op_extent_osd_data(struct ceph_osd_request *osd_req,
-                                unsigned int which,
-                                struct ceph_osd_data *osd_data)
-{
-        BUG_ON(which >= osd_req->r_num_ops);
-        osd_req->r_ops[which].extent.osd_data = osd_data;
-}
-EXPORT_SYMBOL(osd_req_op_extent_osd_data);
-
 void osd_req_op_cls_init(struct ceph_osd_request *osd_req, unsigned int which,
                         u16 opcode, const char *class, const char *method,
                         const void *request_data, size_t request_data_size)
@@ -429,22 +525,13 @@ void osd_req_op_cls_init(struct ceph_osd_request *osd_req, unsigned int which,
         ceph_pagelist_append(pagelist, request_data, request_data_size);
         payload_len += request_data_size;
 
-        op->cls.request_info = &osd_req->r_data_out;
-        ceph_osd_data_pagelist_init(op->cls.request_info, pagelist);
+        osd_req_op_cls_request_info_pagelist(osd_req, which, pagelist);
 
         op->cls.argc = 0;       /* currently unused */
 
         op->payload_len = payload_len;
 }
 EXPORT_SYMBOL(osd_req_op_cls_init);
-void osd_req_op_cls_response_data(struct ceph_osd_request *osd_req,
-                                unsigned int which,
-                                struct ceph_osd_data *response_data)
-{
-        BUG_ON(which >= osd_req->r_num_ops);
-        osd_req->r_ops[which].cls.response_data = response_data;
-}
-EXPORT_SYMBOL(osd_req_op_cls_response_data);
 
 void osd_req_op_watch_init(struct ceph_osd_request *osd_req,
                                 unsigned int which, u16 opcode,
@@ -547,7 +634,6 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
                                                bool use_mempool)
 {
         struct ceph_osd_request *req;
-        struct ceph_osd_data *osd_data;
         u64 objnum = 0;
         u64 objoff = 0;
         u64 objlen = 0;
@@ -561,8 +647,6 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
                                         GFP_NOFS);
         if (!req)
                 return ERR_PTR(-ENOMEM);
-        osd_data = opcode == CEPH_OSD_OP_WRITE ? &req->r_data_out
-                                               : &req->r_data_in;
 
         req->r_flags = flags;
 
@@ -585,7 +669,6 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
 
         osd_req_op_extent_init(req, 0, opcode, objoff, objlen,
                                 truncate_size, truncate_seq);
-        osd_req_op_extent_osd_data(req, 0, osd_data);
 
         /*
          * A second op in the ops array means the caller wants to
@@ -2171,8 +2254,8 @@ int ceph_osdc_readpages(struct ceph_osd_client *osdc,
 
         /* it may be a short read due to an object boundary */
 
-        ceph_osd_data_pages_init(&req->r_data_in, pages, *plen, page_align,
-                                false, false);
+        osd_req_op_extent_osd_data_pages(req, 0, false,
+                                pages, *plen, page_align, false, false);
 
         dout("readpages  final extent is %llu~%llu (%llu bytes align %d)\n",
              off, *plen, *plen, page_align);
@@ -2214,7 +2297,7 @@ int ceph_osdc_writepages(struct ceph_osd_client *osdc, struct ceph_vino vino,
                 return PTR_ERR(req);
 
         /* it may be a short write due to an object boundary */
-        ceph_osd_data_pages_init(&req->r_data_out, pages, len, page_align,
+        osd_req_op_extent_osd_data_pages(req, 0, true, pages, len, page_align,
                                 false, false);
         dout("writepages %llu~%llu (%llu bytes)\n", off, len, len);
 
@@ -2308,8 +2391,14 @@ static struct ceph_msg *get_reply(struct ceph_connection *con,
         m = ceph_msg_get(req->r_reply);
 
         if (data_len > 0) {
-                struct ceph_osd_data *osd_data = &req->r_data_in;
+                struct ceph_osd_data *osd_data;
 
+                /*
+                 * XXX This is assuming there is only one op containing
+                 * XXX page data.  Probably OK for reads, but this
+                 * XXX ought to be done more generally.
+                 */
+                osd_data = osd_req_op_extent_osd_data(req, 0, false);
                 if (osd_data->type == CEPH_OSD_DATA_TYPE_PAGES) {
                         if (osd_data->pages &&
                                 unlikely(osd_data->length < data_len)) {