dm mpath: cleanup 'struct dm_mpath_io' management code

Refactor and rename existing interfaces to be more specific and
self-documenting.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 5b06a94e56e9f8cbb5db358ef41223bdbc8c68b9..2f7c6a550a2d564bec40013548977e9482952fdc 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -228,30 +228,35 @@ static void free_multipath(struct multipath *m)
        kfree(m);
 }
 
-static int set_mapinfo(struct multipath *m, union map_info *info)
+static struct dm_mpath_io *get_mpio(union map_info *info)
+{
+       return info->ptr;
+}
+
+static struct dm_mpath_io *set_mpio(struct multipath *m, union map_info *info)
 {
        struct dm_mpath_io *mpio;
 
        if (!m->mpio_pool) {
                /* Use blk-mq pdu memory requested via per_io_data_size */
-               mpio = info->ptr;
+               mpio = get_mpio(info);
                memset(mpio, 0, sizeof(*mpio));
                return mpio;
        }
 
        mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC);
        if (!mpio)
-               return -ENOMEM;
+               return NULL;
 
        memset(mpio, 0, sizeof(*mpio));
        info->ptr = mpio;
 
-       return 0;
+       return mpio;
 }
 
-static void clear_mapinfo(struct multipath *m, union map_info *info)
+static void clear_request_fn_mpio(struct multipath *m, union map_info *info)
 {
-       /* Only needed for non blk-mq */
+       /* Only needed for non blk-mq (.request_fn) multipath */
        if (m->mpio_pool) {
                struct dm_mpath_io *mpio = info->ptr;
 
@@ -421,11 +426,11 @@ static int __multipath_map(struct dm_target *ti, struct request *clone,
                goto out_unlock;
        }
 
-       if (set_mapinfo(m, map_context) < 0)
+       mpio = set_mpio(m, map_context);
+       if (!mpio)
                /* ENOMEM, requeue */
                goto out_unlock;
 
-       mpio = map_context->ptr;
        mpio->pgpath = pgpath;
        mpio->nr_bytes = nr_bytes;
 
@@ -451,7 +456,7 @@ static int __multipath_map(struct dm_target *ti, struct request *clone,
                                           rq_data_dir(rq), GFP_ATOMIC);
                if (IS_ERR(*__clone)) {
                        /* ENOMEM, requeue */
-                       clear_mapinfo(m, map_context);
+                       clear_request_fn_mpio(m, map_context);
                        return r;
                }
                (*__clone)->bio = (*__clone)->biotail = NULL;
@@ -1317,21 +1322,21 @@ static int multipath_end_io(struct dm_target *ti, struct request *clone,
                            int error, union map_info *map_context)
 {
        struct multipath *m = ti->private;
-       struct dm_mpath_io *mpio = map_context->ptr;
+       struct dm_mpath_io *mpio = get_mpio(map_context);
        struct pgpath *pgpath;
        struct path_selector *ps;
        int r;
 
        BUG_ON(!mpio);
 
-       r  = do_end_io(m, clone, error, mpio);
+       r = do_end_io(m, clone, error, mpio);
        pgpath = mpio->pgpath;
        if (pgpath) {
                ps = &pgpath->pg->ps;
                if (ps->type->end_io)
                        ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
        }
-       clear_mapinfo(m, map_context);
+       clear_request_fn_mpio(m, map_context);
 
        return r;
 }