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Commit 48f7c74a authored by Yuezhang Mo's avatar Yuezhang Mo Committed by Namjae Jeon
Browse files

exfat: reduce the size of exfat_entry_set_cache 



In normal, there are 19 directory entries at most for a file or
a directory.
  - A file directory entry
  - A stream extension directory entry
  - 1~17 file name directory entry

So the directory entries are in 3 sectors at most, it is enough
for struct exfat_entry_set_cache to pre-allocate 3 bh.

This commit changes the size of struct exfat_entry_set_cache as:

                   Before   After
32-bit system      88       32    bytes
64-bit system      168      48    bytes

Signed-off-by: default avatarYuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: default avatarAndy Wu <Andy.Wu@sony.com>
Reviewed-by: default avatarAoyama Wataru <wataru.aoyama@sony.com>
Signed-off-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
parent 54b4c1b2

exfat_fs.h

+21 −4
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/fs.h>

#include <linux/ratelimit.h>

#include <linux/nls.h>

#include <linux/blkdev.h>



#ifndef SECTOR_SIZE

#define SECTOR_SIZE	512
@@ -54,6 +55,14 @@ enum { 
#define ES_2_ENTRIES		2

#define ES_ALL_ENTRIES		0



#define ES_IDX_FILE		0

#define ES_IDX_STREAM		1

#define ES_IDX_FIRST_FILENAME	2

#define EXFAT_FILENAME_ENTRY_NUM(name_len) \

	DIV_ROUND_UP(name_len, EXFAT_FILE_NAME_LEN)

#define ES_IDX_LAST_FILENAME(name_len)	\

	(ES_IDX_FIRST_FILENAME + EXFAT_FILENAME_ENTRY_NUM(name_len) - 1)



#define DIR_DELETED		0xFFFF0321



/* type values */
@@ -81,9 +90,6 @@ enum { 
#define MAX_NAME_LENGTH		255 /* max len of file name excluding NULL */

#define MAX_VFSNAME_BUF_SIZE	((MAX_NAME_LENGTH + 1) * MAX_CHARSET_SIZE)



/* Enough size to hold 256 dentry (even 512 Byte sector) */

#define DIR_CACHE_SIZE		(256*sizeof(struct exfat_dentry)/512+1)



#define EXFAT_HINT_NONE		-1

#define EXFAT_MIN_SUBDIR	2
@@ -138,6 +144,17 @@ enum { 
#define BITS_PER_BYTE_MASK	0x7

#define IGNORED_BITS_REMAINED(clu, clu_base) ((1 << ((clu) - (clu_base))) - 1)



#define ES_ENTRY_NUM(name_len)	(ES_IDX_LAST_FILENAME(name_len) + 1)

/* 19 entries = 1 file entry + 1 stream entry + 17 filename entries */

#define ES_MAX_ENTRY_NUM	ES_ENTRY_NUM(MAX_NAME_LENGTH)



/*

 * 19 entries x 32 bytes/entry = 608 bytes.

 * The 608 bytes are in 3 sectors at most (even 512 Byte sector).

 */

#define DIR_CACHE_SIZE		\

	(DIV_ROUND_UP(EXFAT_DEN_TO_B(ES_MAX_ENTRY_NUM), SECTOR_SIZE) + 1)



struct exfat_dentry_namebuf {

	char *lfn;

	int lfnbuf_len; /* usually MAX_UNINAME_BUF_SIZE */
@@ -179,11 +196,11 @@ struct exfat_hint { 


struct exfat_entry_set_cache {

	struct super_block *sb;

	bool modified;

	unsigned int start_off;

	int num_bh;

	struct buffer_head *bh[DIR_CACHE_SIZE];

	unsigned int num_entries;

	bool modified;

};



struct exfat_dir_entry {