ext4: use unlikely to improve the efficiency of the kernel

Because the function 'sb_getblk' seldomly fails to return NULL
value,it will be better to use 'unlikely' to optimize it.

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index d42a8c49ad692a0eaa449e1edf748b77f1f0ee8f..391e53a52e58f12e6a53cfdf94a2af8e74223305 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -956,7 +956,7 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
                goto cleanup;
        }
        bh = sb_getblk(inode->i_sb, newblock);
-       if (!bh) {
+       if (unlikely(!bh)) {
                err = -ENOMEM;
                goto cleanup;
        }
@@ -1029,7 +1029,7 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
                oldblock = newblock;
                newblock = ablocks[--a];
                bh = sb_getblk(inode->i_sb, newblock);
-               if (!bh) {
+               if (unlikely(!bh)) {
                        err = -ENOMEM;
                        goto cleanup;
                }
@@ -1142,7 +1142,7 @@ static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
                return err;
 
        bh = sb_getblk(inode->i_sb, newblock);
-       if (!bh)
+       if (unlikely(!bh))
                return -ENOMEM;
        lock_buffer(bh);
 

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9ccc140b82d2e73ba677cb2f1576e008081de4a9..93a7e8453a680624f049e5134d0e0ec3dc6fc811 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -713,7 +713,7 @@ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
                return NULL;
 
        bh = sb_getblk(inode->i_sb, map.m_pblk);
-       if (!bh) {
+       if (unlikely(!bh)) {
                *errp = -ENOMEM;
                return NULL;
        }
@@ -3660,7 +3660,7 @@ static int __ext4_get_inode_loc(struct inode *inode,
        iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
 
        bh = sb_getblk(sb, block);
-       if (!bh)
+       if (unlikely(!bh))
                return -ENOMEM;
        if (!buffer_uptodate(bh)) {
                lock_buffer(bh);
@@ -3693,7 +3693,7 @@ static int __ext4_get_inode_loc(struct inode *inode,
 
                        /* Is the inode bitmap in cache? */
                        bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
-                       if (!bitmap_bh)
+                       if (unlikely(!bitmap_bh))
                                goto make_io;
 
                        /*

diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index 44734f1ca55466e28d1d4129cb094b17dae55897..f9b551561d2cc424fa3b512ba3f0d7c4fc51c41b 100644 (file)
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -93,7 +93,7 @@ static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
                        *bh = NULL;
                }
        }
-       if (!*bh) {
+       if (unlikely(!*bh)) {
                ext4_warning(sb, "Error while reading MMP block %llu",
                             mmp_block);
                return -EIO;

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 02824dc2ff3bc52c53cbe291f78b30ef8e5b32c6..05f8d4502d42d1a4c065e84e2150fb093f77644a 100644 (file)
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -333,7 +333,7 @@ static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
        int err;
 
        bh = sb_getblk(sb, blk);
-       if (!bh)
+       if (unlikely(!bh))
                return ERR_PTR(-ENOMEM);
        if ((err = ext4_journal_get_write_access(handle, bh))) {
                brelse(bh);
@@ -410,7 +410,7 @@ static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
                        return err;
 
                bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
-               if (!bh)
+               if (unlikely(!bh))
                        return -ENOMEM;
 
                err = ext4_journal_get_write_access(handle, bh);
@@ -500,7 +500,7 @@ static int setup_new_flex_group_blocks(struct super_block *sb,
                                goto out;
 
                        gdb = sb_getblk(sb, block);
-                       if (!gdb) {
+                       if (unlikely(!gdb)) {
                                err = -ENOMEM;
                                goto out;
                        }
@@ -1064,7 +1064,7 @@ static void update_backups(struct super_block *sb, int blk_off, char *data,
                                        ext4_bg_has_super(sb, group));
 
                bh = sb_getblk(sb, backup_block);
-               if (!bh) {
+               if (unlikely(!bh)) {
                        err = -ENOMEM;
                        break;
                }
@@ -1168,7 +1168,7 @@ static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
 {
        struct buffer_head *bh = sb_getblk(sb, block);
-       if (!bh)
+       if (unlikely(!bh))
                return NULL;
        if (!bh_uptodate_or_lock(bh)) {
                if (bh_submit_read(bh) < 0) {

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 07d684a4e52306cde7fbb4c829d0f936dcfe45c2..c68990c392c79b3594793cd3067a2de8937d73d9 100644 (file)
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -886,7 +886,7 @@ inserted:
                                  (unsigned long long)block);
 
                        new_bh = sb_getblk(sb, block);
-                       if (!new_bh) {
+                       if (unlikely(!new_bh)) {
                                error = -ENOMEM;
 getblk_failed:
                                ext4_free_blocks(handle, inode, NULL, block, 1,