[GFS2] Directory code style changes

As per comments from Jan Engelhardt, remove redundant casts, redundant
endian conversions, add a smattering of const and rewrite the
dirent_next function in order to avoid as many casts as possible.

Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 44 insertions, 48 deletions

diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 2023dc4ea306..d74a52bda540 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -81,9 +81,10 @@
 #define gfs2_disk_hash2offset(h) (((u64)(h)) >> 1)
 #define gfs2_dir_offset2hash(p) ((u32)(((u64)(p)) << 1))
 
-typedef int (*leaf_call_t) (struct gfs2_inode *dip,
-                            u32 index, u32 len, u64 leaf_no,
-                            void *data);
+typedef int (*leaf_call_t) (struct gfs2_inode *dip, u32 index, u32 len, 
+                            u64 leaf_no, void *data);
+typedef int (*gfs2_dscan_t)(const struct gfs2_dirent *dent,
+                            const struct qstr *name, void *opaque);
 
 
 int gfs2_dir_get_new_buffer(struct gfs2_inode *ip, u64 block,
@@ -348,17 +349,13 @@ fail:
         return (copied) ? copied : error;
 }
 
-typedef int (*gfs2_dscan_t)(const struct gfs2_dirent *dent,
-                            const struct qstr *name,
-                            void *opaque);
-
 static inline int __gfs2_dirent_find(const struct gfs2_dirent *dent,
                                      const struct qstr *name, int ret)
 {
         if (dent->de_inum.no_addr != 0 &&
             be32_to_cpu(dent->de_hash) == name->hash &&
             be16_to_cpu(dent->de_name_len) == name->len &&
-            memcmp((char *)(dent+1), name->name, name->len) == 0)
+            memcmp(dent+1, name->name, name->len) == 0)
                 return ret;
         return 0;
 }
@@ -483,8 +480,7 @@ wrong_type:
         return -1;
 }
 
-static struct gfs2_dirent *gfs2_dirent_scan(struct inode *inode,
-                                            void *buf,
+static struct gfs2_dirent *gfs2_dirent_scan(struct inode *inode, void *buf,
                                             unsigned int len, gfs2_dscan_t scan,
                                             const struct qstr *name,
                                             void *opaque)
@@ -500,7 +496,7 @@ static struct gfs2_dirent *gfs2_dirent_scan(struct inode *inode,
 
         offset = ret;
         prev = NULL;
-        dent = (struct gfs2_dirent *)(buf + offset);
+        dent = buf + offset;
         size = be16_to_cpu(dent->de_rec_len);
         if (gfs2_check_dirent(dent, offset, size, len, 1))
                 goto consist_inode;
@@ -512,7 +508,7 @@ static struct gfs2_dirent *gfs2_dirent_scan(struct inode *inode,
                 if (offset == len)
                         break;
                 prev = dent;
-                dent = (struct gfs2_dirent *)(buf + offset);
+                dent = buf + offset;
                 size = be16_to_cpu(dent->de_rec_len);
                 if (gfs2_check_dirent(dent, offset, size, len, 0))
                         goto consist_inode;
@@ -567,6 +563,24 @@ static int dirent_first(struct gfs2_inode *dip, struct buffer_head *bh,
         }
 }
 
+static int dirent_check_reclen(struct gfs2_inode *dip,
+                               const struct gfs2_dirent *d, const void *end_p)
+{
+        const void *ptr = d;
+        u16 rec_len = be16_to_cpu(d->de_rec_len);
+
+        if (unlikely(rec_len < sizeof(struct gfs2_dirent)))
+                goto broken;
+        ptr += rec_len;
+        if (ptr < end_p)
+                return rec_len;
+        if (ptr == end_p)
+                return -ENOENT;
+broken:
+        gfs2_consist_inode(dip);
+        return -EIO;
+}
+
 /**
  * dirent_next - Next dirent
  * @dip: the directory
@@ -579,33 +593,18 @@ static int dirent_first(struct gfs2_inode *dip, struct buffer_head *bh,
 static int dirent_next(struct gfs2_inode *dip, struct buffer_head *bh,
                        struct gfs2_dirent **dent)
 {
-        struct gfs2_dirent *tmp, *cur;
-        char *bh_end;
-        u16 cur_rec_len;
-
-        cur = *dent;
-        bh_end = bh->b_data + bh->b_size;
-        cur_rec_len = be16_to_cpu(cur->de_rec_len);
-
-        if ((char *)cur + cur_rec_len >= bh_end) {
-                if ((char *)cur + cur_rec_len > bh_end) {
-                        gfs2_consist_inode(dip);
-                        return -EIO;
-                }
-                return -ENOENT;
-        }
-
-        tmp = (struct gfs2_dirent *)((char *)cur + cur_rec_len);
+        struct gfs2_dirent *cur = *dent, *tmp;
+        char *bh_end = bh->b_data + bh->b_size;
+        int ret;
 
-        if ((char *)tmp + be16_to_cpu(tmp->de_rec_len) > bh_end) {
-                gfs2_consist_inode(dip);
-                return -EIO;
-        }
+        ret = dirent_check_reclen(dip, cur, bh_end);
+        if (ret < 0)
+                return ret;
 
-        if (cur_rec_len == 0) {
-                gfs2_consist_inode(dip);
-                return -EIO;
-        }
+        tmp = (void *)cur + ret;
+        ret = dirent_check_reclen(dip, tmp, bh_end);
+        if (ret == -EIO)
+                return ret;
 
         /* Only the first dent could ever have de_inum.no_addr == 0 */
         if (!tmp->de_inum.no_addr) {
@@ -614,7 +613,6 @@ static int dirent_next(struct gfs2_inode *dip, struct buffer_head *bh,
         }
 
         *dent = tmp;
-
         return 0;
 }
 
@@ -821,9 +819,9 @@ static struct gfs2_leaf *new_leaf(struct inode *inode, struct buffer_head **pbh,
         gfs2_metatype_set(bh, GFS2_METATYPE_LF, GFS2_FORMAT_LF);
         leaf = (struct gfs2_leaf *)bh->b_data;
         leaf->lf_depth = cpu_to_be16(depth);
-        leaf->lf_entries = cpu_to_be16(0);
+        leaf->lf_entries = 0;
         leaf->lf_dirent_format = cpu_to_be16(GFS2_FORMAT_DE);
-        leaf->lf_next = cpu_to_be64(0);
+        leaf->lf_next = 0;
         memset(leaf->lf_reserved, 0, sizeof(leaf->lf_reserved));
         dent = (struct gfs2_dirent *)(leaf+1);
         gfs2_qstr2dirent(&name, bh->b_size - sizeof(struct gfs2_leaf), dent);
@@ -1152,14 +1150,14 @@ fail:
 
 static int compare_dents(const void *a, const void *b)
 {
-        struct gfs2_dirent *dent_a, *dent_b;
+        const struct gfs2_dirent *dent_a, *dent_b;
         u32 hash_a, hash_b;
         int ret = 0;
 
-        dent_a = *(struct gfs2_dirent **)a;
+        dent_a = *(const struct gfs2_dirent **)a;
         hash_a = be32_to_cpu(dent_a->de_hash);
 
-        dent_b = *(struct gfs2_dirent **)b;
+        dent_b = *(const struct gfs2_dirent **)b;
         hash_b = be32_to_cpu(dent_b->de_hash);
 
         if (hash_a > hash_b)
@@ -1175,9 +1173,7 @@ static int compare_dents(const void *a, const void *b)
                 else if (len_a < len_b)
                         ret = -1;
                 else
-                        ret = memcmp((char *)(dent_a + 1),
-                                     (char *)(dent_b + 1),
-                                     len_a);
+                        ret = memcmp(dent_a + 1, dent_b + 1, len_a);
         }
 
         return ret;
@@ -1246,7 +1242,7 @@ static int do_filldir_main(struct gfs2_inode *dip, u64 *offset,
 
                 gfs2_inum_in(&inum, (char *)&dent->de_inum);
 
-                error = filldir(opaque, (char *)(dent + 1),
+                error = filldir(opaque, (const char *)(dent + 1),
                                 be16_to_cpu(dent->de_name_len),
                                 off, &inum,
                                 be16_to_cpu(dent->de_type));
@@ -1298,7 +1294,7 @@ static int gfs2_dir_read_leaf(struct inode *inode, u64 *offset, void *opaque,
                 return 0;
 
         error = -ENOMEM;
-        larr = vmalloc((leaves + entries) * sizeof(void*));
+        larr = vmalloc((leaves + entries) * sizeof(void *));
         if (!larr)
                 goto out;
         darr = (const struct gfs2_dirent **)(larr + leaves);