fs/adfs: dir: use pointers to access directory head/tails

Add and use pointers in the adfs_dir structure to access the directory
head and tail structures, which will always be contiguous in a buffer.
This allows us to avoid memcpy()ing the data in the new directory code,
making it slightly more efficient.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/adfs/adfs.h

@@ -26,8 +26,6 @@ static inline u16 adfs_filetype(u32 loadaddr)
 #define ADFS_NDA_PUBLIC_READ	(1 << 5)
 #define ADFS_NDA_PUBLIC_WRITE	(1 << 6)
 
-#include "dir_f.h"
-
 /*
  * adfs file system inode data in memory
  */
@@ -98,8 +96,14 @@ struct adfs_dir {
 	unsigned int		pos;
 	__u32			parent_id;
 
-	struct adfs_dirheader	dirhead;
-	union  adfs_dirtail	dirtail;
+	union {
+		struct adfs_dirheader	*dirhead;
+		struct adfs_bigdirheader *bighead;
+	};
+	union {
+		struct adfs_newdirtail	*newtail;
+		struct adfs_bigdirtail	*bigtail;
+	};
 };
 
 /*

fs/adfs/dir_f.c

@@ -58,7 +58,7 @@ static inline void adfs_writeval(unsigned char *p, int len, unsigned int val)
 #define bufoff(_bh,_idx)			\
 	({ int _buf = _idx >> blocksize_bits;	\
 	   int _off = _idx - (_buf << blocksize_bits);\
-	  (u8 *)(_bh[_buf]->b_data + _off);	\
+	  (void *)(_bh[_buf]->b_data + _off);	\
 	})
 
 /*
@@ -139,18 +139,18 @@ static int adfs_dir_read(struct super_block *sb, u32 indaddr,
 	if (ret)
 		return ret;
 
-	memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead));
-	memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail));
+	dir->dirhead = bufoff(dir->bh, 0);
+	dir->newtail = bufoff(dir->bh, 2007);
 
-	if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq ||
-	    memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4))
+	if (dir->dirhead->startmasseq != dir->newtail->endmasseq ||
+	    memcmp(&dir->dirhead->startname, &dir->newtail->endname, 4))
 		goto bad_dir;
 
-	if (memcmp(&dir->dirhead.startname, "Nick", 4) &&
-	    memcmp(&dir->dirhead.startname, "Hugo", 4))
+	if (memcmp(&dir->dirhead->startname, "Nick", 4) &&
+	    memcmp(&dir->dirhead->startname, "Hugo", 4))
 		goto bad_dir;
 
-	if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte)
+	if (adfs_dir_checkbyte(dir) != dir->newtail->dircheckbyte)
 		goto bad_dir;
 
 	return 0;
@@ -275,7 +275,7 @@ static int adfs_f_read(struct super_block *sb, u32 indaddr, unsigned int size,
 	if (ret)
 		adfs_error(sb, "unable to read directory");
 	else
-		dir->parent_id = adfs_readval(dir->dirtail.new.dirparent, 3);
+		dir->parent_id = adfs_readval(dir->newtail->dirparent, 3);
 
 	return ret;
 }
@@ -322,7 +322,6 @@ static int adfs_f_iterate(struct adfs_dir *dir, struct dir_context *ctx)
 static int
 adfs_f_update(struct adfs_dir *dir, struct object_info *obj)
 {
-	struct super_block *sb = dir->sb;
 	int ret;
 
 	ret = adfs_dir_find_entry(dir, obj->indaddr);
@@ -336,33 +335,26 @@ adfs_f_update(struct adfs_dir *dir, struct object_info *obj)
 	/*
 	 * Increment directory sequence number
 	 */
-	dir->bh[0]->b_data[0] += 1;
-	dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 6] += 1;
+	dir->dirhead->startmasseq += 1;
+	dir->newtail->endmasseq += 1;
 
 	ret = adfs_dir_checkbyte(dir);
 	/*
 	 * Update directory check byte
 	 */
-	dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 1] = ret;
+	dir->newtail->dircheckbyte = ret;
 
 #if 1
-	{
-	const unsigned int blocksize_bits = sb->s_blocksize_bits;
-
-	memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead));
-	memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail));
-
-	if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq ||
-	    memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4))
+	if (dir->dirhead->startmasseq != dir->newtail->endmasseq ||
+	    memcmp(&dir->dirhead->startname, &dir->newtail->endname, 4))
 		goto bad_dir;
 
-	if (memcmp(&dir->dirhead.startname, "Nick", 4) &&
-	    memcmp(&dir->dirhead.startname, "Hugo", 4))
+	if (memcmp(&dir->dirhead->startname, "Nick", 4) &&
+	    memcmp(&dir->dirhead->startname, "Hugo", 4))
 		goto bad_dir;
 
-	if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte)
+	if (adfs_dir_checkbyte(dir) != dir->newtail->dircheckbyte)
 		goto bad_dir;
-	}
 #endif
 	ret = 0;
 out:

fs/adfs/dir_fplus.c

@@ -20,7 +20,7 @@ static int adfs_fplus_read(struct super_block *sb, u32 indaddr,
 	if (ret)
 		return ret;
 
-	h = (struct adfs_bigdirheader *)dir->bhs[0]->b_data;
+	dir->bighead = h = (void *)dir->bhs[0]->b_data;
 	dirsize = le32_to_cpu(h->bigdirsize);
 	if (dirsize != size) {
 		adfs_msg(sb, KERN_WARNING,
@@ -40,7 +40,7 @@ static int adfs_fplus_read(struct super_block *sb, u32 indaddr,
 	if (ret)
 		return ret;
 
-	t = (struct adfs_bigdirtail *)
+	dir->bigtail = t = (struct adfs_bigdirtail *)
 		(dir->bhs[dir->nr_buffers - 1]->b_data + (sb->s_blocksize - 8));
 
 	if (t->bigdirendname != cpu_to_le32(BIGDIRENDNAME) ||
@@ -62,11 +62,9 @@ static int adfs_fplus_read(struct super_block *sb, u32 indaddr,
 static int
 adfs_fplus_setpos(struct adfs_dir *dir, unsigned int fpos)
 {
-	struct adfs_bigdirheader *h =
-		(struct adfs_bigdirheader *) dir->bhs[0]->b_data;
 	int ret = -ENOENT;
 
-	if (fpos <= le32_to_cpu(h->bigdirentries)) {
+	if (fpos <= le32_to_cpu(dir->bighead->bigdirentries)) {
 		dir->pos = fpos;
 		ret = 0;
 	}
@@ -77,8 +75,7 @@ adfs_fplus_setpos(struct adfs_dir *dir, unsigned int fpos)
 static int
 adfs_fplus_getnext(struct adfs_dir *dir, struct object_info *obj)
 {
-	struct adfs_bigdirheader *h =
-		(struct adfs_bigdirheader *) dir->bhs[0]->b_data;
+	struct adfs_bigdirheader *h = dir->bighead;
 	struct adfs_bigdirentry bde;
 	unsigned int offset;
 	int ret;