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exfat: reduce the size of exfat_entry_set_cache

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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: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
This commit is contained in:
Yuezhang Mo 2022-11-26 12:39:47 +09:00 committed by Namjae Jeon
parent 54b4c1b260
commit 48f7c74a4c
1 changed files with 21 additions and 4 deletions
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25
exfat_fs.h
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@ -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 {