nilfs2: remove bmap pointer operations

Previously, the bmap codes of nilfs used three types of function
tables.  The abuse of indirect function calls decreased source
readability and suffered many indirect jumps which would confuse
branch prediction of processors.

This eliminates one type of the function tables,
nilfs_bmap_ptr_operations, which was used to dispatch low level
pointer operations of the nilfs bmap.

This adds a new integer variable "b_ptr_type" to nilfs_bmap struct,
and uses the value to select the pointer operations.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 11 insertions, 19 deletions

diff --git a/fs/nilfs2/direct.c b/fs/nilfs2/direct.c
index 8e8095c2e1bb..2a546c8f784e 100644
--- a/fs/nilfs2/direct.c
+++ b/fs/nilfs2/direct.c
@@ -92,8 +92,7 @@ static int nilfs_direct_prepare_insert(struct nilfs_direct *direct,
 
         if (direct->d_ops->dop_find_target != NULL)
                 req->bpr_ptr = direct->d_ops->dop_find_target(direct, key);
-        ret = direct->d_bmap.b_pops->bpop_prepare_alloc_ptr(&direct->d_bmap,
-                                                               req);
+        ret = nilfs_bmap_prepare_alloc_ptr(&direct->d_bmap, req);
         if (ret < 0)
                 return ret;
 
@@ -111,7 +110,7 @@ static void nilfs_direct_commit_insert(struct nilfs_direct *direct,
         bh = (struct buffer_head *)((unsigned long)ptr);
         set_buffer_nilfs_volatile(bh);
 
-        direct->d_bmap.b_pops->bpop_commit_alloc_ptr(&direct->d_bmap, req);
+        nilfs_bmap_commit_alloc_ptr(&direct->d_bmap, req);
         nilfs_direct_set_ptr(direct, key, req->bpr_ptr);
 
         if (!nilfs_bmap_dirty(&direct->d_bmap))
@@ -150,25 +149,18 @@ static int nilfs_direct_prepare_delete(struct nilfs_direct *direct,
 {
         int ret;
 
-        if (direct->d_bmap.b_pops->bpop_prepare_end_ptr != NULL) {
-                req->bpr_ptr = nilfs_direct_get_ptr(direct, key);
-                ret = direct->d_bmap.b_pops->bpop_prepare_end_ptr(
-                        &direct->d_bmap, req);
-                if (ret < 0)
-                        return ret;
-        }
-
-        stats->bs_nblocks = 1;
-        return 0;
+        req->bpr_ptr = nilfs_direct_get_ptr(direct, key);
+        ret = nilfs_bmap_prepare_end_ptr(&direct->d_bmap, req);
+        if (!ret)
+                stats->bs_nblocks = 1;
+        return ret;
 }
 
 static void nilfs_direct_commit_delete(struct nilfs_direct *direct,
                                        union nilfs_bmap_ptr_req *req,
                                        __u64 key)
 {
-        if (direct->d_bmap.b_pops->bpop_commit_end_ptr != NULL)
-                direct->d_bmap.b_pops->bpop_commit_end_ptr(
-                        &direct->d_bmap, req);
+        nilfs_bmap_commit_end_ptr(&direct->d_bmap, req);
         nilfs_direct_set_ptr(direct, key, NILFS_BMAP_INVALID_PTR);
 }
 
@@ -289,11 +281,11 @@ static int nilfs_direct_propagate_v(struct nilfs_direct *direct,
         if (!buffer_nilfs_volatile(bh)) {
                 oldreq.bpr_ptr = ptr;
                 newreq.bpr_ptr = ptr;
-                ret = nilfs_bmap_prepare_update(&direct->d_bmap, &oldreq,
-                                                &newreq);
+                ret = nilfs_bmap_prepare_update_v(&direct->d_bmap, &oldreq,
+                                                  &newreq);
                 if (ret < 0)
                         return ret;
-                nilfs_bmap_commit_update(&direct->d_bmap, &oldreq, &newreq);
+                nilfs_bmap_commit_update_v(&direct->d_bmap, &oldreq, &newreq);
                 set_buffer_nilfs_volatile(bh);
                 nilfs_direct_set_ptr(direct, key, newreq.bpr_ptr);
         } else